STORAGE BATTERY TROUBLES.
-------------------------
The Storage Battery is a most faithful servant, and if given even a
fighting chance, will respond instantly to the demands made upon it.
Given reasonable care and consideration, it performs its duties
faithfully for many months. When such care is lacking, however, it is
soon discovered that the battery is subject to a number of diseases,
most of which are "preventable," and all of which, if they do not kill
the battery, at least, greatly impair its efficiency.
In discussing these diseases, we may consider the various parts of
which a battery is composed, and describe the troubles to which they
are subject. Every battery used on an automobile is composed of:
1. Plates
2. Separators
3. Jars in which Plates, Separators, and Electrolyte are placed
4. Wooden case
5. Cell Connectors, and Terminals
6. Electrolyte
Most battery diseases are contagious, and if one part fails, some of
the other parts are Affected. These diseases may best be considered in
the order in which the parts are given in the foregoing list.
PLATE TROUBLES
Plates are the "vitals" of a battery, and their troubles affect the
life of the battery more seriously than those of the other parts. It
is often difficult to diagnose their troubles, and the following
descriptions are given to aid in the diagnosis.
Sulphation
1. Over discharge. Some battery men say that a battery is suflphated
whenever anything is wrong with it. Sulphation is the formation of
lead sulphate on the plates. As a battery of the lead acid type
discharges, lead sulphate must form. There can be no discharge of such
a battery without the formation of lead sulphate, which is the natural
product of the chemical reactions by virtue of which current may be
drawn from the battery. This sulphate gradually replaces the lead
peroxide of the positive plate, and the spongy lead of the negative
plate. When a battery has been discharged until the voltage per cell
has fallen to the voltage limits, considerable portions of the lead
peroxide and spongy lead remain on the plates. The sulphate which is
then present is in a finely divided, porous condition, and can readily
be changed back to lead peroxide and spongy lead by charging the
battery.
If the discharge is continued after the voltage has fallen to the
voltage limits, an excessive amount of sulphate forms. It fills up the
pores in the active materials, and covers up much of the active
material which remains, so that it is difficult to change the sulphate
back to active material. Moreover, the expansion of active material
which takes place as the sulphate forms is then so great that it
causes the active material to break off from the plate and drop to the
bottom of the jar.
2. Allowing a Battery to Stand Idle. When lead sulphate is first
formed, it is in a finely divided, porous condition, and the
electrolyte soaks through it readily. If a battery which has been
discharged is allowed to stand idle without being charged, the lead
sulphate crystals grow by the combination of the crystals to form
larger crystals. The sulphate, instead of having a very large surface
area, upon which the electrolyte may act in changing the sulphate to
active material, as it does when it is first formed, now presents only
a very small surface to the electrolyte, and it is therefore only with
great difficulty that the large crystals of sulphate are changed to
active material. The sulphate is a poor conductor, and furthermore, it
covers up much of the remaining active material so that the
electrolyte cannot reach it.
A charged battery will also become sulphated if allowed to stand idle,
because it gradually becomes discharged, even though no wires of any
kind are attached to the battery terminals. How this takes place is
explained later. The discharge and formation of sulphate continue
until the battery is completely discharged. The sulphate then
gradually forms larger crystals as explained in the preceding
paragraph, until all of the active material is either changed to
sulphate, or is covered over by the sulphate so that the electrolyte
cannot reach it. The sulphate thus forms a high resistance coating
which hinders the passage of charging current through the battery and
causes heating on charge. It is for this reason that sulphated plates
should be charged at a low rate. The chemical actions which are
necessary to change the sulphate to active material can take place but
very slowly, and thus only a small current can be absorbed. Forcing a
large current through a sulphated battery causes heating since the
sulphate does not form uniformly throughout the plate, and the parts
which are the least sulphated will carry the charging current, causing
them to become heated. The heating damages the plates and separators,
and causes buckling, as explained later.
If batteries which have been discharged to the voltage limits are
allowed to stand idle without being charged, they will, of course,
continue to discharge themselves just as fully charged batteries do
when allowed to stand idle.
3. Starvation. If a battery is charged and discharged intermittently,
and the discharge is greater than the charge, the battery will never
be fully charged, and lead sulphate will always be present. Gradually
this sulphate forms the large tough crystals that cover the active
material and remove it from action. This action continues until all
parts of the plate are covered with the crystalline sulphate and we
have the same condition that results when a battery is allowed to
stand idle without any charge.
4. Allowing Electrolyte to Fall Below Tops of Plates. If the
electrolyte is allowed to fall below the tops of the plates, so that
the active materials are exposed to the air, the parts thus exposed
will gradually become sulphated. The spongy lead of the negative
plate, being in a very finely divided state, offers a very large
surface to the oxygen of the air, and is rapidly oxidized, the
chemical action causing the active material to become hot. The
charging current, in passing through the parts of the plates not
covered by the electrolyte also heats the active materials. The
electrolyte which occasionally splashes over the exposed parts of the
plates and which rises in the pores of the separators, is heated also,
and since hot acid attacks the active materials readily, sulphation
takes place quickly. The parts above the electrolyte, of course,
cannot be charged and sulphate continues to form. Soon the whole
exposed parts are sulphated as shown in Fig. 209.
As the level of the electrolyte drops, the electrolyte becomes
stronger, because it is only the water which evaporates, the acid
remaining and becoming more and more concentrated. The remaining
electrolyte and the parts of the plates covered by it become heated by
the current, because there is a smaller plate area to carry the
current, and because the resistance of the electrolyte increases as it
grows more concentrated. Since hot acid attacks the active materials,
sulphation also takes place in the parts of the plates still covered
by the electrolyte.
The separators in a battery having the electrolyte below the tops of
the plates suffer also, as will be explained later. See page 346.
5. Impurities. These are explained later. See page 76.
6. Adding Acid Instead of Water. The sulphuric acid in the electrolyte
is a heavy, oily liquid that does not evaporate. It is only the water
in the electrolyte which evaporates. Therefore, when the level of the
electrolyte falls, only water should be added to bring the electrolyte
to the correct height. There are, however, many car owners who still
believe that a battery may be charged by adding acid when the level of
the electrolyte falls. Batteries in which this is done then contain
too much acid. This leads to two troubles. The first is that the
readings taken with a hydrometer will then be misleading. A specific
gravity of 1.150 is always taken to indicate that a battery is
discharged, and a specific gravity of 1.280 that a battery is charged.
These two values of specific gravity indicate a discharged and charged
condition of the battery ONLY WHEN THE PROPORTION OF ACID IN THE
ELECTROLYTE IS CORRECT. It is the condition of the plates, and not the
specific gravity of the electrolyte which determines when a battery is
either charged or discharged. With the correct proportion of acid in
the electrolyte, the specific gravity of the electrolyte is 1.150 when
the plates are discharged and 1.280 when the plates are charged, and
that is why specific gravity readings are generally used as an
indication of the condition of the battery.
If there is too much acid in the electrolyte, the plates will be in a
discharged condition before the specific gravity of the electrolyte
drops to 1.150, and will not be in a charged condition until after the
specific gravity has risen beyond the usual value. As a result of
these facts a battery may be over-discharged, and never fully charged,
this resulting in the formation of sulphate.
The second trouble caused by adding acid to the electrolyte is that
the acid will then be too concentrated and attacks both plates and
separators. This will cause the plates to become sulphated, and the
separators rotted.
7. Overheating. This was explained in Chapter 9. See page 66.
Buckling
Buckling is the bending or twisting of plates due to unequal expansion
of the different parts of the plate, Figs. 207 and 208. It is natural
and unavoidable for plates to expand. As a battery discharges, lead
sulphate forms. This sulphate occupies more space than the lead
peroxide and spongy lead, and the active materials expand. Heat
expands both active materials and grids. As long as all parts of a
plate expand equally, no buckling will occur. Unequal expansion,
however, causes buckling.
1. Over discharge. If discharge is carried too far, the expansion of
the active material on account of the formation of lead sulphate will
bend the grids out of shape, and may even break them.
2. Continued Operation with Battery in a Discharged Condition. When a
considerable amount of lead sulphate has, formed, and current is still
drawn from the battery, those portions of the plate which have the
least amount of sulphate will carry most of the current, and will
therefore become heated and expand. The parts covered with sulphate
will not expand, and the result is that the parts that do expand will
twist the plate out of shape. A normal rate of discharge may be
sufficient to cause buckling in a sulphated plate.
3. Charging at High Rates. If the charging rate is excessive, the
temperature will rise so high that excessive expansion will take
place. This is usually unequal in the different parts of the plate,
and buckling results. With a battery that has been over discharged,
the charging current will be carried by those parts of the plates
which are the least sulphated. These parts will therefore expand while
others will not, and buckling results.
4. Non-Uniform Distribution of Current Over the Plates. Buckling may
occur in a battery which has not been over-discharged, if the current
carried by the various parts of the plate is not uniform on account of
faulty design, or careless application of the paste. This is a fault
of the manufacturers, and not the operating conditions.
5. Defective Grid Alloy. If the metals of which the grids are composed
are not uniformly mixed throughout the plate, areas of pure lead may
be left here and there, with air holes at various points. The
electrolyte enters the air holes, attacks the lead and converts the
grid partly into active material. This causes expansion and consequent
distortion and buckling.
Buckling will not necessarily cause trouble, and batteries with
buckled plates may operate satisfactorily for a long time. If,
however, the expansion and twisting has caused much of the active
material to break away from the grid, or has loosened the active
material from the grids, much of the battery capacity is lost. Another
danger is that the lower edges of a plate may press against the
separator with sufficient force to cut through it, touch the next
plate, and cause a short-circuit.
Shedding, or Loss of Active Material
The result of shedding, provided no other troubles occur, is simply to
reduce the capacity of the plates. The positives, of course, suffer
more from shedding than the negatives do, shedding being one of the
chief weaknesses of the positives. There is no remedy for this
condition. When the shedding has taken place to such an extent that
the capacity of the battery has fallen very low, new plates should be
installed. After a time, the sediment space in the bottom of the jar
becomes filled with sediment, which touches the plates. This
short-circuits the cell, of course, and new plates must be installed,
and the jars washed out thoroughly.
1. Normal Shedding. It is natural and unavoidable for the positives to
shed. Lead Peroxide is a powder-like substance, the particles of which
do not hold together. A small amount of sulphate will cement the
particles together to a considerable extent. At the surface of the
plate, however, this sulphate is soon changed to active material, and
the peroxide loses its coherence. Particles of peroxide drop from the
plates and fall, into the space in the bottom of the jar provided for
this purpose.
Bubbles of gas which occur at the end of a charge blow some of the
peroxide particles from the plate. The electrolyte moving about as the
battery is jolted by the motion of the car washes particles of
peroxide from the positive plates. Any slight motion between positive
plates and separators rubs some peroxide from the plates. It is
therefore entirely natural for shedding to occur, especially at the
positives. The spongy lead of the negatives is much more elastic than
the peroxide, and hence very little shedding occurs at the negative
plates. The shedding at the positives explains why the grooved side of
the separator is always placed against the positive plate. The
grooves, being vertical, allow the peroxide to fall to the bottom of
the jar, where it accumulates as sediment, or "mud."
2. Excessive Charging Rate, or Overcharging. If a battery is charged
at too high a rate, only part of the current is used to produce the
chemical actions by which the battery is charged. The balance of the
current decomposes the water of the electrolyte into hydrogen and
oxygen, causing gassing. As the bubbles of gas force their way out of
the plates, they blow off particles of the active material.
When a battery is overcharged, the long continued gassing has the same
effect as described in the preceding paragraph.
3. Charging Sulphated Plates at too High a Rate. In sulphated plates,
the chemical actions which take place as a battery is charged can
proceed but very slowly, because the sulphate, besides being a poor
conductor, has formed larger crystals which present only a small
surface for the electrolyte to act upon, and has also covered up much
of the remaining active material. Since the chemical actions take
place slowly, the charging current must be kept at a low value. If too
heavy a charging current is used, the battery will be overheated, and
some of the current will simply cause gassing as explained in No. 2
above. The gas bubbles will break off pieces of the sulphate, which
then fall to the bottom of the jars as "mud."
4. Charging Only a Part of the Plate. If the electrolyte falls below
the tops of the plates, and the usual charging current is sent into
the battery, the current will be too great for the plate area through
which it passes, and hence gassing and shedding will result as already
explained.
The same condition exists in a battery in which one or more plates
have been broken from the strap, either because of mechanical
vibration or because of impurities such as acetic acid in improperly
treated separators. The remaining plates are called upon to do more
work, and carry the entire charging current. Gassing and shedding will
result.
5. Freezing. If a battery is given any care whatever, there is little
danger of freezing. The electrolyte of a fully charged battery with a
specific gravity of 1.280 freezes at about 92° below zero. With a
specific gravity of 1.150, the electrolyte freezes at about 5° above
zero. A frozen battery therefore indicates gross neglect.
As the electrolyte freezes, the water of the electrolyte expands.
Since there is electrolyte in all the inner parts of the plate, the
expansion as the water in the paste freezes forces the pastes out of
the grids. The expansion also cracks the rubber jars, and sometimes
bulges out the ends of the battery case.
Loose Active Material
This refers to a condition in which the active materials are no longer
in contact with the grid. Corrosion, or sulphation, of the grids
themselves is generally present at the same time, since the chemical
actions are shifted from the active material to the grids themselves.
1. Over discharge. As a battery discharges, the lead sulphate which
forms causes an expansion of the active material. If a battery is
repeatedly over-discharged, this results in the positives shedding. In
the negatives, the spongy lead is puffed out, resulting in the
condition known as "bulged negatives" as illustrated in Fig 122.
2. Buckling. As a plate grid is bent out of shape, the active
material, especially the peroxide, breaks loose from the grid, since
the peroxide cannot bend as much as the grids. This occurs in the
negatives also, though not to such an extent as in the positives.
If the plates are buckled to such an extent that the element will not
go back into the jar, the positives should be discarded. If the
positives are buckled, the negatives will be also, but not to the
extent that the positives are.
In the case of the positives, there is no remedy, and the plates
should be discarded. The negatives, however, may be fully charged, and
then straightened, and the active material forced back flush with the
grids by pressings, as described in Chapter 15.
Impurities
Impurities may be divided into two general classes. The first class
includes those which do not attack the separators or grids, but merely
cause internal self-discharge. The second class includes those which
attack the grids or separators.
1. Impurities Which Merely Cause Self-discharge. This includes metals
other than lead. If these metals are in solution in the electrolyte,
they deposit on the negative plate, during charge, in their ordinary
metallic state, and form small cells with the spongy lead. These small
cells discharge as soon as the charging circuit is opened, and some of
the lead is changed to lead sulphate. This, of course, causes a loss
in capacity. Free hydrogen is given off by this local discharge, and
so much of it is at times given off that the hydrogen bubbles give the
electrolyte a milky appearance.
Silver, gold, and platinum are the most active in forming small local
cells. These metals form local cells which have comparatively high
voltages, and which take away a considerable portion of the energy of
a cell. Platinum is especially active, and a small amount of platinum
will prevent a negative plate from taking a charge. Gradually,
however, the spongy lead covers up the foreign metal and prevents it
from forming local cells.
Iron also forms local cells which rob the cell of a considerable
portion of its capacity. This may be brought into the cell by impure
acid or water. Iron remains in solution in the electrolyte, and is not
precipitated as metallic iron. The iron in solution travels from the
positive to the negative plate, and back again, causing a local
discharge at each plate. It is, moreover, very difficult to remove the
iron, except by pouring out all of the electrolyte. Manganese acts the
same as the iron.
2. Impurities Which Attack the Plates. In general, this class includes
acids other than sulphuric acid, compounds formed from such acids, or
substances which will readily form acids by chemical action in the
cell. Nitric acid, hydrochloric or muriatic acid, and acetic acid
belong in this class of impurities. Organic matter in a state of
decomposition attacks the lead grids readily.
Impurities in the second class dissolve the lead grids, and the plate
disintegrates and falls to pieces, since its backbone is destroyed.
When a battery which contains these impurities is opened, it will be
found that the plates crumble and fall apart at the slightest touch.
See Fig. 210.
Separators which have not been treated properly introduce acetic acid
into a cell. The acetic acid attacks and rots the lead, especially the
lugs projecting above the electrolyte, and the plate connecting
straps. The plates will generally be found broken from the connecting
strap, with the plate lugs broken and crumbled.
As for remedies, there is not much to be done. Impurities in the first
class merely decrease the capacity of the battery. If the battery is
fully charged, and the negatives then washed thoroughly, some of the
impurities may be removed. Impurities of the second class have
generally damaged the plates beyond repairs by the time their presence
is suspected.
The best thing to do is to keep impurities out of the battery. This
means that only distilled water, which is known to be absolutely free
from impurities should be used.
Impurities which exist in the separators or acid cannot be detected
readily, but in repairing a battery, separators furnished by one of
the reliable battery makers should be used. Pure acid should also be
used. This means that only chemically pure, or "C. P." acid, also
known as battery acid should be used. In handling the acid in the
shop, it should always be kept in its glass bottle, and should be
poured only into a glass, porcelain, earthenware, lead, or rubber
vessel. Never use a vessel made of any other material.
Corroded Grids
When the grids of a plate are attacked chemically, they become thin
and weak, and may be spoken of as being corroded.
1. Impurities. Those impurities which attack the lead grids, such as
acids other than sulphuric acid, compounds formed from these acids, or
substances which will readily form acids dissolve some of the lead
which composes the grids. The grids gradually become weakened. The
decrease in the amount of metal in the grids increases the internal
resistance of the cell and give a tendency for temperatures to be
higher in the cell. The contact between grids and active material is
in time made poor. If the action of the impurities continues for any
length of time, the plate becomes very weak, and breaks at the
slightest touch.
2. High Temperatures. Anything that raises the temperature of the
electrolyte, such as too high a charging rate, causes the acid to
attack the grids and form a layer of sulphate on them. The sulphate is
changed to active material on charge, and the grids are thereby
weakened.
3. Age. Grids gradually become weak and brittle as a battery remains
in service. The acid in the electrolyte, even though the electrolyte
has the correct gravity and temperature, has some effect upon the
grids, and in time this weakens them. During the life of a battery it
is at times subjected to high temperatures, impurities, sulphation,
etc., the combined effects of which result in a gradual weakening of
the grids.
Granulated Negatives
1. Age. The spongy lead of the negative plate gradually assumes a
"grainy" or "granulated" appearance. The lead then seems to be made up
of small grains, like grains of sand, instead of being a smooth paste.
This action is a natural one, and is due to the gradual increase in
the size of the particles of the lead. The plate loses its porosity,
the particles cementing together and closing the pores in the lead.
The increase in the size of the particles of the spongy lead decreases
the amount of surface exposed to the action of the electrolyte, and
the plate loses capacity. Such plates should be thrown away, as
charging and discharging will not bring the paste back to its original
state.
2. Heat will also cause the paste to become granulated, and its
surface to become rough or even blistered.
Heating of Negatives Exposed to the Air
When charged negatives are exposed to the air, there is a decided
increase in their temperature. Spongy lead is in an extremely finely
divided state, the particles of lead being very minute, and forming a
very porous mass. When the plate is exposed to the air, rapid
oxidation takes place because the oxygen of the air has a very large
surface to act upon. The oxidation causes the lead to become heated.
The heating, of course, raises the temperature of the electrolyte, and
the hot acid attacks both grids and lead.
Fully charged negatives should therefore be watched carefully when
removed from a battery. When they become heated and begin to steam,
they should be dipped in water until they have cooled. They may then
be removed from the water, but should be dipped whenever they begin to
steam. After they no longer heat, they may be left exposed to the air.
This method of dipping the negatives to prevent overheating has always
been followed. However, the Electric Storage Battery Company, which
makes the Exide batteries, does not take any steps to prevent the
heating of the negatives when exposed to the air, stating that their
plates are not injured by the heating which takes place.
Negatives With Very Hard Active Material
This is the characteristic condition of badly sulphated negatives. The
active material may be as hard as a stone. The best method of treating
such negatives is to charge them in distilled water. See Chapter 15.
Bulged Negatives
This is a characteristic of a repeatedly over-discharged negative. The
lead sulphate which forms as a battery discharges is bulkier than the
spongy lead, and the lead expands and bulges out between the ribs of
the grid.
Negative With Soft, Mushy Active Material
1. High Gravity. Gravity above 1.300 causes the acid to act upon the
spongy lead and soften it.
2. Heat will soften the spongy lead also. The softened spongy lead is
loosened and falls from the grids, as shown in Fig. 211. Little can be
done for such negatives.
Negatives With Roughened Surface
This is caused by slight overheating, and is not a serious condition.
Frozen Positives
A battery which is allowed to stand in a cold place while completely
discharged will freeze. The water in the electrolyte expands as it
freezes, cracking the rubber jars and bulging out the end of the
wooden case. As the electrolyte which fills the pores of the positive
plates freezes and expands, it breaks the active material loose from
the grids. When the battery thaws, the active material does not go
back into the grids. When such a battery is opened, and the groups
separated, the positive active material sticks to the separators in
large pieces, Fig. 112, and that remaining in the grids falls out very
easily. The active material has a pinkish color and is badly shrunken.
Rotted, Disintegrated Positives
1. Impurities. This has already been discussed. See page 76.
2. Overheating. The hot electrolyte dissolves the lead of the grids
and that which is dissolved is never converted back to lead. Continued
overheating wears out the grids, and the active material also, and the
plate falls to pieces at the slightest pressure.
3. Age. Positives gradually disintegrate due to the prolonged action
of the electrolyte on the grids, an occasional overheating, occasional
use of impure water, etc.
Positives which are rotted and disintegrated are, of course, hopeless,
and must be junked.
Buckled Positives
As previously described, buckling is caused by unequal expansion. If
the buckling is only slight, the plates may be used as they are. If
the plates are badly buckled, the active material will be found to be
loose, and the plates cannot be straightened. Such positives should be
discarded.
Positives That Have Lost Considerable Active Material
This is the result of continued shedding, the causes of which have
already been given. If the shedding is only slight, and the plate is
good otherwise, it may be used again. If such active material has been
lost, the plates must be discarded.
Positives With Soft Active Material
Continued operation at high temperatures, will soften the peroxide,
and make the plates unfit for further use. Old positives are soft,
clue to the natural deterioration of the paste with age.
Positives With Hard, Shiny Active Material
This condition is found in batteries that have been charged with the
acid below the tops of the plates. The part of the plate above the
acid is continually being heated by the charging current. It becomes
hard and shiny, and has cracks running through it. The peroxide
becomes orange or brick colored, and the grid deteriorates. The part
of the plate below the electrolyte suffers also, as explained more
fully on page 71. Such plates should be discarded if any considerable
portion of the plates is affected. Plates in which 1/2 to 1 inch of
the upper parts are affected may be used again if otherwise in good
condition.
Plates Which Have Been Charged in Wrong Direction
Such plates have been partly reversed, so that there is lead peroxide
and spongy lead on both positive and negative plates, and such plates
are generally worthless. If the active materials have not become
loosened from the grids, and the grids have not been disintegrated and
broken, the plates may sometimes be reversed by a long charge at a low
rate in the right direction. If this does not restore the plates,
discard them.
SEPARATOR TROUBLES
Separators form the weakest part of a battery, but at the same time
perform a very important duty. New separators should therefore be
installed whenever a battery is opened for repairs. Repairs should
never be attempted on separators.
1. Not Properly Expanded Before Installation. Separators in stock must
be kept moist. This not only prevents them from becoming dry and
brittle, but keeps them fully expanded. If separators which have been
kept dry in stock are installed in a battery, they do their expanding
inside the battery. This causes them to project beyond the edges of
the plates. The crowding to which they are subjected causes them to
crack. Cracked separators permit "treeing" between plates, with a
consequent short circuit.
2. Not Properly Treated. Separators which have not been given the
proper chemical treatment are likely to develop Acetic acid after they
are in the battery. Acetic acid dissolves the lead grids, the plate
lugs, and the plate connecting straps rapidly. If the plate lugs are
found broken, and crumble easily, acetic acid is very likely present,
especially if an odor like that of vinegar is noticeable. Improperly
treated separators will cause a battery to show low voltage at high
rates of discharge, particularly in cold weather, and will also cause
the negatives to give poor cadmium readings, which may lead the
repairman to conclude that the negatives are defective. The
separators of batteries which have been shipped completely assembled
without electrolyte and with moistened plates and separators will
sometimes have the same effect.
3. Cracked. Separators should be carefully "candled"--placed in front
of a light and looked through. Cracks, resinous streaks, etc., mean
that the separator should not be used, as it will breed trouble.
4. Rotted and Carbonized. This may be the result of old age,
overheating, or high gravity electrolyte.
5. Pores Clogged. Impurities, dirt from impure water, and lead
sulphate fill the pores of a separator and prevent the proper
circulation of the electrolyte. The active material of frozen
positives also fills up the pores of a separator.
6. Edges Chiseled Off. A buckling plate will cut through the lower
edge of a separator and short circuit the cell. Holes will be cut
through any part of a separator by a buckling plate, or a negative
with bulged active material.
JAR TROUBLES
Battery jars are made of hard rubber, and are easily broken. They are
not acted upon by the electrolyte, or any of the impurities which may
be found in the jar. Their troubles are all mechanical, and consist of
being cracked, or having small holes through the walls. Jars are
softened by high temperatures, but this does no particular harm unless
they are actually burned by an open flame or red hot metal. The causes
of jar troubles are as follows:
1. Rough Handling. By far the most common cause of jar breakage is
rough handling by careless or inexperienced persons. If one end of a
battery rests on the floor, and the other is allowed to drop several
inches, broken jars will probably result from the severe impact of the
heavy lead plates. Storage batteries should be handled as if made of
glass. When installed on a car, the springs protect the battery from
shock to a considerable extent, but rough roads or exceptionally
severe jolts may break jars.
2. Battery Not Properly Fastened. In this case a battery is bumped
around inside the battery compartment, and damage is very likely to
result.
3. Any Weight Placed on Top of the Battery is transmitted from the
links to the plates, and by them to the bottom of the jars. Batteries
should always be stored in racks, and not one on top of another. The
practice of putting any weight whatever on top of a battery should be
promptly discouraged.
4. Freezing. This condition has already been explained. It causes a
great many broken jars every winter.
5. Groups Not Properly Trimmed. The outside negative plates in a cell
come just inside the jar, and the strap ends must be carefully trimmed
off flush with the plates, to prevent them from breaking the top of
the jars. Jars have slightly rounded corners, and are somewhat
narrower at the extreme ends than nearer the center. A group may
therefore go into a jar quite readily when moved toward the other end
of the jar to that into which the post strap must go when in proper
position for the cover. When the group is forced back into its proper
position the strap may break the jar. It is a good plan not only to
trim the ends of the negative straps perfectly flush, but to round the
strap corners where they go into the jar corners.
6. Defective Jars. (a) A jar not properly vulcanized may come apart at
the scam. (b) A small impurity in the rubber may dissolve in the acid
and leave a minute pinhole. All jars are carefully tested at the
factory and the likelihood of trouble from defective jars is extremely
small.
7. Explosion in Cell. (a) Hydrogen and oxygen gases evolved during
charging make a very explosive mixture. An open flame brought near a
battery on charge or freshly charged, will probably produce an
explosion resulting in broken jars and jar covers. (b) An open circuit
produced inside a cell on charge in the manner described on page 86
under the heading "Open Circuits," will cause a spark at the instant
the circuit is broken, with the same result as bringing a flame near
the battery. (c) The small holes in the vents must be kept free for
the escape of the gases. These holes are usually sealed in batteries
shipped with moistened plates and separators, to keep air out of the
cells. The seals must be removed when the battery is prepared for
service. If the vents remain plugged, the pressure of the gases formed
during charge will finally burst the covers of jars.
BATTERY CASE TROUBLE
1. Ends Bulged Out. This may be due to a battery having been frozen or
to hold-downs being screwed down too tight, or some similar cause.
Whether the case can be repaired depends on the extent of the bulging.
This can best be determined by the repairman.
2. Rotted. If the case is rotted around the top, it is evidence that:
(a) Too much water was added, with subsequent overflowing when
electrolyte warmed up during charge. (b) The tops were poorly sealed,
resulting in leaks between the covers and the jars. (c) Battery has
not been fastened down properly, and acid has been thrown out of the
jars by the jolting of the car on the road. (d) The vent plugs have
not been turned down tightly. (e) Electrolyte has been spilled in
measuring specific gravity.
If the case is rotted around the lower part it indicates that the jars
are cracked or contain holes. Instructions for making repairs on
battery cases are given on page 360.
TROUBLE WITH CONNECTORS AND TERMINALS
1. Corroded. This is a very common trouble, and one which should be
guarded against very carefully. Corrosion is indicated by the presence
of a grayish or greenish substance on the battery terminals,
especially the positive. It is due to several causes:
(a) Too much water added to cells. The electrolyte expands on charge
and flows out on the top of the battery.
(b) Battery not fastened firmly. The jolting caused by the motion of
the car on the road will cause electrolyte to be thrown out of the
vent caps.
(c) Battery poorly sealed. The electrolyte will be thrown out on the
cover by the motion of the car through the leaks which result from
poor sealing.
(d) Vent caps loose. This also allows electrolyte to be thrown out on
the battery top.
(e) Electrolyte spilled on top of battery in measuring specific
gravity.
(f) Battery cables damaged, or loose. The cables attached to the
battery terminals are connected to lugs which are heavily coated with
lead. The cables are insulated with rubber, upon which sulphuric acid
has no effect. Care should be taken that the lead coating is not worn
off, and that the rubber insulation is not broken or cut so as to
allow electrolyte, which is spilled on the battery top as explained in
(a), (b), (c), (d) and (e), to reach the bare copper conductors of the
cable. The terminal parts are always so made that when the connections
are kept tight no acid can come into contact with anything but lead
and rubber, neither of which is attacked by sulphuric acid.
(g) Attaching wires directly to battery terminals. There should be no
exposed metal except lead at the battery terminals. No wires of any
other metal should be attached to the battery terminals. Such wires
should be connected to the rubber covered cables which are attached to
battery, and the connections should be made far enough away from the
battery to prevent electrolyte from coming in contact with the wire.
Car manufacturers generally observe this rule, but the car owner may,
through ignorance, attach copper wires directly to the battery
terminals. The positive terminal is especially subject to corrosion,
and should be watched carefully. To avoid corrosion it is necessary
simply to keep the top of the battery dry, keep the terminal
connections tight, and coat the terminals with vaseline. The rule
about connecting wires directly to the battery terminals must of
course be observed also.
2. Loose. Loose terminal connections cause a loss of energy due to
their resistance, and all such connections must be well made. If the
inter-cell connectors are loose, it is due to a poor job of lead
burning. This is also true of burned on terminals, and in either case,
the connections should be drilled off, cleaned and re-burned.
Terminals sometimes become so badly corroded that it is impossible to
disconnect the cables front the battery. Stitch terminals should be
drilled off and soaked in boiling soda water.
ELECTROLYTE TROUBLES
(1) Low Gravity. See page 321.
(2) High Gravity. See page 323.
(3) Low Level. See page 323.
(4) High Level. This condition is due to the addition of too much
water. It leads to corrosion as already explained. It also causes a
loss of acid. The Electrolyte which overflows is lost, this of course,
causing a loss of acid. The condition of Low Gravity then arises, as
described on page 321.
(5) Specific gravity will not rise during charge. See page 204.
(6) Milky Electrolyte:
(a) Lead Sulphate in Battery Acid. It sometimes happens that sulphuric
acid contains some lead sulphate in solution. This sulphate is
precipitated when water is added to the acid in mixing electrolyte,
and gives the electrolyte a milky appearance. This sulphate settles if
the electrolyte is allowed to stand.
(b) Gassing. The most common cause of the milky appearance, however,
is the presence of minute gas bubbles in large quantities. These may
be the result of local action caused by the presence of metallic
impurities in the battery. The local action will stop when the battery
is put on charge, but will begin as soon as the battery is taken off
charge. The impurities are gradually covered by lead or lead sulphate,
and the local action is thus stopped.
Excessive gassing in a cell which contains no impurities may also
cause the electrolyte to have a milky appearance. The gas bubbles are
very numerous and make the electrolyte look milky white.
(c) Impurities in the electrolyte will also give it a milky appearance.
GENERAL TROUBLES
Open Circuits
1. Poor Burning of Connectors to Posts. Unless a good burned
connection is made between each connector and post, the joint may melt
under high discharge rates, or it may offer so much resistance to the
passage of current that the starting motor cannot operate. Sometimes
the post is not burned to the connector at all, although the latter is
well finished off on top. Under such conditions the battery may
operate for a time, due to frictional contact between the post and
connector, but the parts may become oxidized or sulphated, or
vibration may break the connection, preventing the flow of current.
Frequently, however, the circuit is not completely open, and the poor
connection acts simply as a high resistance. Under such a condition
the constant current generator automatically increases its voltage,
and forces charging current through the battery, although the latter,
having only a low fixed voltage, cannot force out the heavy current
required for starting the engine.
2. Terminals Broken Off. Inexperienced workmen frequently pound on the
terminals to loosen the cable lugs, or pry on them sufficiently to
break off the battery terminals. If the terminals and lugs are kept
properly greased, they will come apart easily. A pair of terminal
tongs is a very convenient tool. These exert a pressure between the
terminal and the head of the terminal screw, which is first unscrewed
a few turns.
3. Acid on Soldered Joints. Amateurs sometimes attempt to make
connections by the use of a soldering iron and solder. Solder is
readily dissolved by acid, not only spoiling the joint, but
endangering the plates if any gets into the cells. Solder must never
be used on a battery except for sweating the cables into the cable
lugs, and the joint even here must be well protected by rubber tape.
4. Defective Posts. Posts withdrawn from the post mould before they
are cool enough may develop cracks. Bubbles sometimes occur in the
posts. Either trouble may reduce the current carrying capacity or
mechanical strength of the post and result in a broken or burned-out
spot.
5. Plates Improperly Burned. As previously explained, this is not
likely to cause immediate trouble, but by imposing extra work on the
balance of the plates, causes them to wear out quickly.
Battery Discharged
1. Due to excessive use of starting motor and lamps.
2. Failure of generator.
3. Defective switches, which by being grounded, or failing to open
allow battery to discharge.
4. Defective cutout, allowing battery to discharge into generator.
5. Addition of accessories, or use of too large lamps.
6. Defective wiring, causing grounds or short-circuits.
7. Insufficient charging rate.
8. Battery allowed to remain idle.
Dead Cells
1. Worn out Separators. The duties of separators are to prevent the
plates from touching each other, and to prevent "treeing," or growth
of active material from the negative to the positive plates. If they
fail to perform these duties, the battery will become short-circuited
internally. The separator troubles described on page 81 eventually
lead to short-circuited cells.
2. Foreign Material. If a piece of lead falls between plates so as to
later punch a hole through a separator, a short circuit will result.
Great care should be taken in burning plates on the straps to prevent
lead from running down between plates, as this lead will cause a short
circuit by punching through the separator.
3. Accumulation of Sediment. The active material which drops from the
plates accumulates in the "mud" space in the bottom of the jar. If
this rises until it touches the bottom of the plates, a short-circuit
results. Usually it is advisable to renew the positives in a battery
which has become short-circuited by sediment, since the sediment comes
largely from the positives, and if they have lost enough active
material to completely fill the sediment space, they are no longer fit
for use.
4. Badly sulphated plates and separators, impurities which attack the
plates.
Loss of Capacity
A battery loses capacity due to a number of causes. Some of them have
already been considered.
1. Impurities in the Electrolyte. These have already been discussed.
2. Sulphation. This also has been described.
3. Loose Active Material, as already described. The active materials
which are not in contact with the grids cannot do their work.
4. Incorrect Proportions of Acid and Water in the Electrolyte. In
order that all the active material in the plates may be utilized,
there must be enough acid in the electrolyte, and also enough water.
If there is not enough acid, the battery will lack capacity. If there
is too much acid, the acid when the battery is fully charged will be
strong enough to attack and seriously damage the plates and
separators. Insufficient amount of acid may be due to replacing, with
water, electrolyte which has been spilled or which has leaked out. Too
much acid results from an incorrect proportion of acid and water in
the electrolyte, or from adding acid instead of water to bring the
electrolyte above the plate tops, and causes sulphation, corroded
plates, and carbonized separators.
The remedy for incorrect proportions of acid and water in the
electrolyte is to give the battery a full charge and adjust the
gravity by drawing off some of the electrolyte and replacing it with
water, or 1.400 specific gravity electrolyte, as the case may require.
5. Separators Clogged. The pores of the separators may become filled
with sulphate or impurities, and thus prevent the proper circulation
of the electrolyte. New separators must be put in.
6. Shedding. The capacity of a battery naturally decreases as the
active material falls from the plates, since the amount of active
material which can take part in the chemical actions that enable us to
draw current from the battery decreases.
7. Low Level of Electrolyte. Aside from the loss of capacity which
results from the sulphation caused by low electrolyte, there is a loss
of capacity caused by the decrease in the useful plate area when the
electrolyte is below the tops of the plates. Only that part of the
plate surface which is below the electrolyte does any work, and the
area of this part gradually decreases as the electrolyte falls.
8. Reversal of Plates. If one cell of a battery has an internal short
circuit, or some other defect which causes it to lose its charge, the
cell will be discharged before the others which are in series with it,
and when this cell is completely discharged, the other cells will send
a current through it in a discharge direction, and the negative plates
will have a coating of lead peroxide formed on them, and will assume
the characteristics of positive plates. The positives will be reversed
also.
This reversal may also be the result of charging a battery in the
wrong direction, on account of reversed charging connections. The
remedy for reversed plates, provided they have not become
disintegrated, is to give them a long charge in the right direction at
a low rate.
9. Effect of Age. A battery gradually loses capacity due to its age.
This effect is independent of the loss of capacity due to the other
causes. In the negatives, the size of the grain increases its size,
giving the plates a granulated appearance. Stitch plates are called
"granulated" negatives. The spongy lead cements together and loses
porosity.
Loss of Charge in An Idle Battery
It has been found that if a charged battery is allowed to stand idle,
and is not charged, and no current is drawn from it, the battery will
gradually become completely discharged and must be given an occasional
"freshening" charge.
Now, as we have learned, when a battery discharges lead sulphate forms
on each plate, and acid is taken from the electrolyte as the sulphate
forms. In our idle battery, therefore, such actions must be taking
place. The only difference in this case is that the sulphate forms
without any current passing through the battery.
At the lead peroxide plate we have lead peroxide paste, lead grid, and
sulphuric acid. These are all the element-, needed to produce a
storage battery, and as the lead peroxide and the lead are touching
each other, each lead peroxide plate really forms a short circuited
cell. Why does this plate not discharge itself completely? A certain.
amount of discharge does take place, and results in a layer of lead
sulphate forming between the lead peroxide and the grid. The sulphate,
having high resistance then protects the lead grid and prevents any
further action. This discharge action therefore does not continue, but
causes a loss of a certain part of the charge.
At the negative plate, we have pure spongy lead, and the grid. This
grid is not composed entirely of lead, but contains a percentage of
antimony, a metal which makes the grid harder and stronger. There is
but very little difference of potential between the spongy lead and
the grid. A small amount of lead sulphate does form, however, on the
surface of the negative plate. This is due to the action between the
spongy lead and the electrolyte.
Some of the lead combines with the acid to form lead sulphate, but
after a small amount has been formed the action is stopped because a
balanced chemical condition is soon obtained.
Thus only a small amount of lead sulphate is formed at each plate, and
the cell thereby loses only a small part of its charge. In a perfectly
constructed battery the discharge would then stop. The only further
action which would take place would be the slow evaporation of the
water of the electrolyte. The loss of charge which actually occurs in
an idle charged battery is greater than that due to the formation of
the small amounts of sulphate on the plates, and the evaporation of
the water from the electrolyte.
Does an idle cell discharge itself by decomposing its electrolyte? We
have a difference of potential of about two volts between the lead and
lead peroxide plate. Why is the electrolyte not decomposed by this
difference? At first it might seem that the water and acid should be
separated into its parts, and hydrogen liberated at the negative
plate. As a matter of fact, very little hydrogen gas is set free in an
idle charged cell because to do so would require a voltage of about
2.5. At two volts, so little gas is formed that the loss of charge due
to it may be neglected entirely.
The greatest loss of charge in an idle battery results from conditions
arising from the processes of manufacture, internal troubles, and
leakage between terminals. The grids of a cell are an alloy of lead
and antimony. These are mixed while in a molten condition, and are
then allowed to cool. If the cooling is not done properly, or if a
poor grade of antimony is used, the resulting grid is not a uniform
mixture of antimony and lead. There will be areas of pure lead, with
an air hole here and there. The lack of uniformity in the grid
material results in a local discharge in the grid. This causes some
loss of charge.
If the active material completely fills the spaces between the grids,
the acid formed as the cell is charged may not be able to diffuse into
the main body of the electrolyte, but forms a small pocket of acid in
the plate. This acid will cause a discharge between paste and grid and
a coating of lead sulphate forms on the arid, resulting in a certain
loss of charge.
In general any metallic impurity in a cell will cause a loss at the
lead plate. When a cell is charged, the current causes the metals to
deposit on the lead plate. Local cells are formed by the metallic
impurity, the lead plate, and the acid, and these tiny cells will
discharge completely, causing a loss of charge. This has already been
described on page 76.
Another cause of loss of charge in an idle cell is leakage of current
between the terminals on the outside of the battery. During charge,
the bubbles of gas which escape from the electrolyte carry with them
minute quantities of acid which may deposit on the top of the battery
and gradually form a thin conducting layer of electrolyte through
which a current will flow from the positive to the negative terminals.
This danger may be avoided by carefully wiping any moisture from the
battery. Condensation of moisture from the air, on the top or sides
and bottom of a battery will cause the same condition. This will be
especially noticeable if a battery is kept in a damp place.
The tendency for crystals of lead to "tree" over from the negative to
the positive plates is well known. An idle battery is one in which
this action tends to take place. Treeing will occur through the pores
of the separators and as there is no flow of electrolyte in or out of
the plates, the lead "trees" are not disturbed in their growth. A
freshening charge causes this flow to take place, and break up the
"trees" which would otherwise gradually short circuit the cells.
========================================================================
Section II
------------------------------------------------------------------------
Shop Equipment
Shop Methods
========================================================================
CHAPTER 11.
CARE OF THE BATTERY ON THE CAR.
-------------------------------
Any man who goes into the battery repair business will gradually learn
by experience what equipment he finds necessary for his work. Some men
will be able to do good work with comparatively little equipment,
while others will require a somewhat elaborate layout.
[Fig 38.]
Fig. 38. Typical Work Room Showing Bench About 34 Inches High, Lead
Burning Outfit, Hot Plates for Melting Sealing Compound and Hand
Drill-Press for Drilling off Inter-Cell Connectors.
There are some things, however, which are necessary, and the following
lists are given to help the repairman select his equipment. The man
with limited capital will be unable to buy a complete equipment at the
start, but he should add to his equipment as fast as his earnings will
permit. The repairman may be able to "get-by" with crude equipment
when his business is very small, but to make his business grow he must
absolutely have good equipment.
The following list gives the various articles in the order of their
importance. The first seven are absolutely necessary, even for the
poorest beginner. The others are also essential, but may be bought as
soon, as the money begins to come in. Some of the tools must also be
bought before opening doors for business, such as the putty knife,
screwdrivers, pliers, and so on. Each article, which requires
explanation, is described in detail, beginning on page 100.
Equipment Which is Absolutely Necessary
1. Charging Outfit, such as a motor-generator set, rectifier, or
charging resistance where direct current is available.
2. Charging Bench and Accessories. With the charging bench must go the
following:
1. A syringe-hydrometer for measuring specific gravity of
electrolyte, for drawing off electrolyte and for adding water to
cells.
2. A special battery thermometer for measuring temperature of
electrolyte.
3. A voltmeter to measure cell, battery, and cadmium voltages.
4. An ammeter to measure charging current.
5. A glass bottle for distilled water. Also one for electrolyte.
6. A number of eighteen inch lengths of No. 12 flexible wire fitted
with lead coated test clips, for connecting batteries in series
while on charge.
3. Work bench with vise.
4. Sink or wash tank and water supply.
5. Lead-burning outfit. (This should properly be called a lead welding
outfit, since it is used to melt lead parts so that they will be
welded together.)
6. For handling sealing compound, the following are necessary.
1. Stove.
2. Pot in which compound is melted.
3. An iron ladle for dipping up the melted compound.
4. One or two old coffee pots for pouring compound.
7. Shelving or racks for batteries waiting to be repaired, batteries
which have been repaired, rental batteries, new batteries, battery
boxes, battery jars, battery plates, etc.
8. Bins for battery parts, such as covers, inter-cell connectors,
plate straps, terminals, handles, vent plugs, hold down bolts,
separator hold-downs, and so on.
Equipment Needed In Opening Batteries
9. A battery steamer for softening sealing-compound and making covers
limp, for softening compound around defective jars which are to be
removed, for softening jars which are to be set in a battery box, and
so on.
10. Putty knife to remove softened scaling compound.
11. One ratchet brace with set of wood bits or square shank drills of
the following sizes: 3/8, 5/8, 3/4, 13/16, and 7/8 inch, for drilling
off terminals and inter-cell connectors. A power drill press, or a
portable electric drill will save time and labor in drilling off the
terminals and connectors.
12. Center punch for marking terminals and connectors before drilling.
13. Ten inch screwdriver for prying off connectors and terminals which
have been drilled. The screwdriver may, of course, be used on various
other kinds of work also.
14. A ten-inch length of 3/4 inch angle iron to protect upper edge of
case when prying off the connectors and terminals which have been
drilled.
15. Two pairs of standard combination pliers for lifting elements out
of jars. A pair of six or eight inch gas pliers will also do for this
work.
16. Machinist hammer. This is, of course, also used for other purposes.
17. Terminal tongs for removing taper lugs from terminals.
18. Pair of long, fiat nosed pliers for pulling out separators and
jars.
19. Open-end wrench for use in removing taper lugs from terminals.
Equipment for Lead Burning (Welding)
In addition to the lead burning-outfit, the following tools are needed:
20. A plate burning rack for setting up plates which are to be burned
to a plate strap.
21. A plumber's or tinner's triangular scraper for cleaning surfaces
which are to be welded together. A pocketknife will do in a pinch.
22. Steel wire brush for cleaning surfaces which are to be welded
together. This may also be used for general cleaning of lead parts.
23. Coarse files, vixen, round, and flat, for filing lead parts.
24. Set of burning, collars to be used in burning inter-cell
connectors to posts.
25. Moulds for casting sticks of burning lead. A pot for melting lead
is needed with the mould, and mould compound is also needed.
26. Set of post builders-moulds used for building up posts which have
been drilled short in removing terminals and intercell connectors.
27. Pair of blue or smoked glasses to be worn when using lead burning
outfit.
Equipment for General Work on Cell Connectors and Terminals
28. Set of moulds for casting inter-cell connectors, terminals,
terminal screws, taper lugs, plate straps and posts, etc.
29. Set of reamers to ream holes in terminals and connectors.
30. Set of hollow reamers for reducing posts.
Equipment for Work on Cases
31. Cans of asphaltum paint for painting cases. May also be used for
acid-proofing work benches, floor, shelves, charging bench, and so on.
32. Paint brushes, one wide and several narrow.
33. Battery turntable.
34. Several wood chisels of different sizes.
35. Small wood-plane for smoothing up top edges of case.
36. Large glazed earthenware jars of washing or baking soda solution
for soaking cases to neutralize acid.
Tools and Equipment for General Work
37. One pair of large end cutting nippers for cutting connectors,
posts, plate lugs, and so on.
38. One pair of 8 inch side cutting pliers.
39. One pair of 8 inch diagonal cutting pliers.
40. Several screwdrivers.
41. Adjustable hacksaw frame with set of coarse blades.
42. Gasoline torch.
42. Soldering iron, solder and flux.
44. Separator cutter.
45. Plate press for pressing bulged, spongy lead of negative plates
flush with surface of grids.
46. Battery carrier.
47. Battery truck.
48. Lead lined box for storing separators. A large glazed earthenware
jar may be used for this purpose, and is much cheaper, although it
will not hold as many separators, on account of its round shape, as
the lead lined box.
49. Several old stew pans for boiling acid soaked terminals,
connectors, covers, etc., in a solution of washing soda.
50. Set of metal lettering stamps, for stamping POS and NEG on battery
terminals, repairman's initials, date battery was repaired, and nature
of repairs, on inter-cell connectors.
51. Cadmium test set.
52. High rate discharge testers.
53. Pair of rubber gloves to protect hands when handling acid.
54. Rubber apron to protect clothing from acid.
55. Pair of rubber sleeve protectors.
56. Rubbers to protect shoes, or pair of low rubber boots.
57. Tags for tagging repair and rental batteries, batteries in
storage, etc.
58. Pot of paraffine which may be heated, and paper tags dipped after
date has been written on tag in pencil. A 60-watt lamp hung in the can
may be used for heating the compound. In this way the tag is protected
from the action of acid, and the writing on the tag cannot be rubbed
off or made illegible.
59. A number of wooden boxes, about 12 inches long, 8 inches wide, and
4 inches deep, in which are placed terminals, inter-cell connectors,
covers, vent plugs, etc., of batteries being repaired.
60. Several large glazed earthenware jars are convenient for waste
acid, old separators, and general junk, which would otherwise litter
up the shop.
Stock
61. A supply of spare parts, such as cases, jars, covers, plate
straps, inter-cell connectors, plates, vent plugs, etc., should be
kept.
62. A supply of sealing compound is necessary.
63. A carboy of pure acid, and carboys of 1.400 electrolyte ready for
use should be on hand. A 16 oz. and a 32 or 64 oz. graduate are very
useful in measuring out acid and water.
64. A ten gallon bottle of distilled water is necessary for use in
making up electrolyte, for addition to cell electrolyte to bring
electrolyte up to proper level, and so on. If you wish to distill
water yourself, buy a water still.
65. A supply of pure vaseline is necessary for coating terminals to
prevent corrosion.
Special Tools
Owing to special constructions used oil sonic of the standard makes of
batteries, special tools are required, and such tools should be
obtained if work is done oil these batteries. Some of these tools are
as follows:
66. Special wrenches for turning sealing nuts on Exide batteries.
67. Two hollow reamers (post-freeing tools) for cutting lead seal
around posts of Prest-O-Lite batteries. There are two sizes, large and
small, see page 389.
68. Style "B" peening press for sealing posts of Prest-O-Lite
batteries to covers, see page 390.
69. Pressure tongs for forcing lead collar oil posts of Vesta
batteries, see page 415.
70. Special wrench for tightening sealing nut oil Titan batteries.
71. Special reamer for cutting sealing ring oil Universal batteries.
The list of special tools is not intended to be complete, and the
repairman will probably find other special tools necessary from time
to time. In any case, it is best to buy from the battery manufacturer
such special tools as are necessary for the batteries that come in for
repairs. It is sometimes possible to get along without the special
tools, but time and labor will be saved by using them.
DESCRIPTIONS OF TOOLS AND EQUIPMENT NAMED IN FOREGOING LIST
Charging Equipment
A battery is charged by sending a direct current through it, this
"charging" current entering the battery at, the positive terminal and
passing out at the negative terminal. To send this current through the
battery, a voltage of about 7.5 volts is applied to each battery.
Two things are therefore necessary in charging a battery:
1. We must have a source of direct current.
2. The voltage impressed across each battery must be, about 2.5 per
cell. The charging voltage across each six volt battery must
therefore be 7.5, and for each twelve volt battery the charging
voltage must be about 15 volts.
With the battery on the car, there are two general methods of
charging, i. e., constant potential (voltage) and constant current.
Generators having a constant voltage regulator have a constant voltage
of about 7.5, the charging current depending upon the condition of the
battery. A discharged battery thus receives a high charging current,
this current gradually decreasing, or "tapering" as the battery
becomes more fully charged. This system has the desirable
characteristic that a discharged battery receives a heavy charging
current, and a fully charged battery receives a small charging
current. The time of charging is thereby decreased.
With a constant-current charging system, the generator current output
is maintained at a certain value, regardless of the state of charge of
the battery. The disadvantage of this system is that a fully charged
battery is charged at as high a rate and in most cases at a higher
rate than a discharged battery.
In the shop, either the constant-potential, or the constant-current
system of charging may be used. Up to the present time, the constant
current system has been used in the majority of shops. The equipment
for constant current charging uses a lamp bank or rheostat to regulate
the charging current where direct current is available, and a
rectifier or motor-generator set where only alternating current is
available. Recently, the Hobart Brothers Company of Troy, Ohio, has
put on the market a constant potential motor-generator set which gives
the same desirable "tapering" charge as does the constant voltage
generator on the car. This set will be described later.
Where a 110-volt direct current supply is available, fifteen 6-volt
batteries may be connected in series across the line without the use
of any rheostat or lamp bank, only an ammeter being required in the
circuit to indicate the charging current. The charging rate may be
varied by cutting out some of the batteries, or connecting more
batteries in the circuit. This method is feasible only where many
batteries are charged, since not less than fifteen 6-volt batteries
may be charged at one time.
Constant Current Charging
Using Lamp Banks, or Rheostats
Figures 39 and 40 show the wiring for a "bank" of twenty 100-watt
lamps for battery charging from a 110 volt line. Figure 39 shows the
wiring to be used when the positive side of the line is grounded,
while Figure 40 shows the wiring to be used when the negative side of
the line is grounded. In either case, the "live" wire connects to the
lamp bank. The purpose of this is to eliminate the possibility of a
short-circuit if any part of the charging line beyond the lamp bank is
accidentally grounded.
[Fig. 39 Lamp bank for charging from a 110 volts, D.C. Line
(positive grounded)]
[Fig. 40 Lamp bank for charging from a 110 volts, D.C. Line
(negative grounded)]
[Fig. 41 Rheostat for charging from a 110 volts, D.C. Line
(positive grounded)]
[Fig. 42 Rheostat for charging from a 110 volts, D.C. Line
(negative grounded)]
Figures 41 and 42 show the wiring of two charging rheostats which may
be used instead of the lamp banks shown in Figures 39 and 40. In these
two rheostats the live wire is connected to the rheostat resistances
in order to prevent short-circuits by grounding any part of the
circuit beyond the rheostats. These rheostats may be bought ready for
use, and should not be "homemade." The wiring as shown in Figures 41
and 42 is probably not the same as will be found on a rheostat which
may be bought, but when installing a rheostat, the wiring should be
examined to make sure that the "live" wire is connected to the
rheostat resistance and does not connect directly to the charging
circuit. If necessary, change the wiring to agree with Figures 41 and
42.
Figures 43 and 44 show the wiring of the charging circuits. In Figure
43 each battery has a double pole, double throw knife switch. This is
probably the better layout, since any battery may be connected in the
circuit by throwing down the knife switch, and any battery may be cut
out by throwing the switch up. With this wiring layout, any number of
batteries from one to ten may be cut-in by means of the switches.
Thus, to charge five batteries, switches 1 to 5 are thrown down, and
switches 5 to 10 are thrown up, thereby short-circuiting them.
[Fig. 43 Wiring for a charging circuit, using a DPDT switch for
each battery; and Fig. 44 Wiring for a charging circuit, using
jumpers to connect batteries in series]
Figure 44 shows a ten-battery charging circuit on which the batteries
are connected in series by means of jumpers fitted with lead coated
test clips, as shown. This layout is not as convenient as that shown
in Figure 43, but is less expensive.
Using Motor-Generator Sets
[Fig. 45 Ten battery motor-generator charging set]
Where no direct current supply is available, a motor-generator or a
rectifier must be installed. The motor-generator is more expensive
than a rectifier, but is preferred by some service stations because it
is extremely flexible as to voltage and current, is easily operated,
is free from complications, and has no delicate parts to cause trouble.
Motor-Generator sets are made by a number of manufacturers.
Accompanying these sets are complete instructions for installation and
operation, and we will not attempt to duplicate such instructions in
this book. Rules to assist in selecting the equipment will, however,
be given.
Except in very large service stations, a 40 volt generator is
preferable. It requires approximately 2.5 volts per cell to overcome
the voltage of a battery in order to charge it, and hence the 40 volt
generator has a voltage sufficient to charge 15 cells in series on one
charging line. Five 6 volt batteries may therefore be charged at one
time on each line. With a charging rate of 10 amperes, each charging
line will require 10 times 40, or 400 watts. The size of the generator
will depend on the number of charging lines desired. With 10 amperes
charging current per line, the capacity of the generator required will
be equal to 400 watts multiplied by the number of charging lines. One
charging line will need a 400 watt outfit. For two charging lines 800
watts are required. Each charging line is generally provided with a
separate rheostat so that its charging rate may be adjusted to any
desired value. This is an important feature, as it is wrong to charge
all batteries at the same rate, and with separate rheostats the
current on each line may be adjusted to the correct value for the
batteries connected to that line. Any number of batteries up to the
maximum may be charged on each line.
[Fig. 46 Thirty-two battery motor-generator charging set]
In choosing a charging outfit, it is important not to get one which is
too large, as the outfit will operate at a loss when running under a
minimum load. It is equally important not to get one which is too
small, as it will not be able to take care of the batteries fast
enough, and there will be a "waiting list" of batteries which cannot
be charged until others are taken off charge. This will prevent the
giving of good service. Buy an outfit that will care for your needs in
the future, and also operate economically at the present time. Most
men going into the battery business make the mistake of
underestimating their needs, and getting equipment which must soon be
discarded because of lack of capacity.
The manufacturers each make a number of sizes, and the one which will
best fill the requirements should be chosen. In selecting an outfit
the manufacturer's distributor or dealer should be consulted in
deciding what size outfit to obtain. The particular outfit will depend
on the voltage and frequency of the alternating current power
circuits, the maximum charging current desired (10 amperes per line is
ample), and the greatest number of batteries to be charged at one time.
For the beginner, a 500 watt ten battery outfit, as shown in Fig. 45,
is suitable. For the medium sized garage that specializes in battery
charging, or for the small battery service station, a one kilowatt
outfit is most satisfactory. Two charging panels are generally
furnished with this outfit, and two charging lines may thus be used.
This is an important feature, as one line may be used in starting a
charge at 10 amperes, and the other for charging the batteries, that
have begun to gas, at a reduced rate. Fig. 46 shows a 2 K. W.
four-circuit, 32 battery motor-generator set. Each circuit is provided
with a separate rheostat and ammeter. The two terminals near the top
of each rheostat are connected to one charging circuit. The two
terminals near the lower end of each rheostat are connected to the
generator.
The 2 kilowatt set is suitable for a city garage, or a battery service
station in a medium sized town. A beginner should not purchase this
large set, unless the set can be operated at at least one-fourth
capacity continuously. As a service station grows, a 5 kilowatt set
may be needed. The 1, 2 and 5 kilowatt sets should not be used on
anything but city power lines. Single phase, or lighting lines are not
satisfactory for handling these sets.
A few suggestions on Motor-Generator Sets
1. Installation. Set the motor-generator on as firm a foundation as
possible. A good plan is to bolt it to a heavy bench, in which
position it is easily inspected and adjusted, and is also less likely
to be hit by acid spray, water, etc.
Set the motor-generator at some distance from the batteries so that
acid spray and fumes will not reach it. Sulphuric acid will attack any
metal and if you are not careful, your motor-generator may be damaged
seriously. The best plan is to have the motor generator set outside of
the charging room, so as to have a wall or partition between the
motor-generator and the batteries. The charging panels may be placed
as near the batteries as necessary for convenience, but should not be
mounted above the batteries. Figure 47 shows a convenient layout of
motor-generator, charging panels, and charging benches. Note that the
junipers used in connecting the batteries together are run through the
upper holes of the wire porcelain insulating cleats, the lower hole of
each insulator supporting the wire from the charging panel which runs
to the end of the bench.
[Fig. 47]
Fig. 47. Convenient Arrangement of Motor-Generator, Charging Panels,
and Charging Benches
Instructions for the wiring connections to the power lines generally
come with each outfit, and they should be followed carefully. Fuses in
both the motor and generator circuits are especially important, as
they protect the machines from damage due to overloads, grounds, or
short-circuits. The generator must be driven in the proper direction
or the generator will not build up. The rotation of a three-phase
motor may be reversed by reversing, and Charging Benches any two of
the cables. To reverse a two-phase motor, reverse the cables of either
phase. Before putting a motor-generator set into operation, be sure to
check all connections to make sure that everything checks with the
instructions furnished by the manufacturer.
Operating the Charging Circuits
A generator operates most efficiently when delivering its rated
output. Therefore, keep the generator as fully loaded as possible at
all times. When you do not have enough batteries to run the generator
at full load, run each charging circuit at full load, and use as few
circuits as possible. This will reduce your power bill, since there is
a loss of power in the rheostat of each charging circuit, this loss
being the greatest when only one battery is on the circuit, and a
minimum when the circuit is fully loaded.
With several charging circuits, it is also possible to put batteries
which are in the same condition on one circuit and adjust the charging
rate to the most suitable value. Thus, badly sulphated batteries,
which must be charged at a low rate, may be put on the same circuit,
while batteries which have had only a normal discharge may be put oil
another circuit and charged at a higher rate. As each battery becomes
almost fully charged, it may be removed from the circuit and put on
another circuit and the charge completed at the finishing rate. This
is a good practice, since some batteries will begin to gas sooner than
others, and if the charging rate is not reduced, the batteries which
have begun to gas will have active material blown out by the continued
gassing. A careful study of such points will lead to a considerable
saving in power costs.
Care of Motor-Generator Set
A. Machine will not build up or generate. This may be due to:
1. Machine rotating in wrong direction.
2. Brushes not making good contact. Clean commutator with fine
sandpaper.
3. Wrong connections of field rheostat-check connections with
diagram.
4. Open circuit in field rheostat. See if machine will build up
with field rheostat cut out.
B. Excessive heating of the commutator. This may be due to:
1. Overload--Check your load and compare it with nameplate
reading. Add the total amperes on all the panels and see that it
does not exceed the ampere reading on the nameplate.
2. Wrong setting of the brush rocker arm. This causes sparking,
which soon will cause excessive heating.
3. Rough commutator. This will cause the brushes to chatter, be
noisy and spark. Caused many times by allowing copper to accumulate
on the bottom of the brushes.
4. Insufficient pressure on brushes, resulting in sparking. This
may be due to brushes wearing down to the point where the brush
lead screw rests on the brush holder.
5. Dirt and grease accumulating between the brush and brush holder
causing brush to stick; brush must always move freely in the holder.
6. Brush holder may have come loose, causing it to slip back,
relieving brush press-Lire.
7. Brush spring may have become loosened, releasing the tension.
8. Watch commutator carefully and keep it in the best of condition.
There will not be excessive heating without sparking. Excessive
sparking may raise the temperature so high as to cause throwing of
solder. You can avoid all this by taking proper care of the
commutator.
C. Ammeters on Panels Read Reverse: This is caused by improperly
connecting up batteries, which has reversed the polarity of the
generator. This generally does no harm, since in most cases the
batteries will automatically reverse the polarity of the generator.
Generally the condition may be remedied by stopping the machine,
reversing the batteries and starting the machine again. If this is
unsuccessful raise the brushes on the machine. Connect five or six
batteries in series in the correct way to one panel, while the machine
is not in operation. Turn on the panel switch. When the machine is
started, it will then build up in the right direction. If it does not
do so, repeat the above, using a larger number of batteries.
D. Machine Refuses to Start. If there is a humming noise when you try
to start the motor, and the outfit does not start, one of the fuses
needs replacing. The outfit will hum only on two or three phase
current. Never leave the power turned on with any of the fuses out.
Constant-Potential Charging
In the Constant-Potential system of battery charging, the charging
voltage is adjusted to about 7.5, and is held constant throughout the
charge. With this system a discharged battery receives a heavy current
when it is put on charge. This current gradually decreases as the
battery charges, due to the increasing battery voltage, which opposes,
or "bucks" the charging voltage, and reduces the voltage which is
effective in sending current through the batteries. Such a charge is
called "tapering" charge because the charging current gradually
decreases, or "tapers" off.
The principle of a "tapering" charge is, of course, that a discharged
battery may safely be charged at a higher rate than one which is only
partly discharged, because there is more lead sulphate in the
discharged battery which the action of the current changes back to
active material. As the battery charges, the amount of lead sulphate
decreases and since there is less sulphate for the current to act
upon, the charging rate should be reduced gradually. If this is not
done, excessive gassing will occur, resulting in active material being
blown from the grids.
A battery which has been badly sulphated, is of course, in a
discharged condition, but is not, of course, able to absorb a heavy
charging rate, and in handling such batteries on a constant potential
system, care must be taken that the charging rate is low. Another
precaution to be observed in all constant potential charging is to
watch the temperature of batteries while they are drawing a heavy
charging current. A battery which gasses soon after it is put oil
charge, and while still in a discharged condition, should be taken off
the line, or the charging line voltage reduced. With constant
potential charging, as with constant current charging, the two things
to watch are temperature and gassing. Any charging rate which does not
cause an excessive temperature or early gassing is safe, and
conversely any charging rate which causes an excessive battery
temperature, or causes gassing while the battery is still less than
three-fourths charged, is too high.
[Fig. 48]
Fig. 48. Hobart Bros. Co. 3 K. W. Constant Potential Motor-Generator
Charging Set
The Constant-Potential Charging Set manufactured by the Hobart Bros.
Co., consists of a 3 K.W. generator rated at 7.5 volts, and 400
amperes. This generator is direct connected to a 5 H.P. motor, both
machines being mounted oil the same base plate. Figure 48 shows this
outfit. Note that for the charging line there are three bus-bars to
which the batteries are connected. Twelve volt batteries are connected
across the two outside bus-bars, while six volt batteries are
connected between the center bus-bar and one of the outer ones.
The Tungar Rectifier
[Fig. 49 Tungar rectifier bulb]
All rectifiers using oil are operated on the principle that current
can pass through them in one direction only, due to the great
resistance offered to the flow of current in the opposite direction.
It is, of course, not necessary to use mercury vapor for the arc. Some
rectifiers operate on another principle. Examples of such rectifiers
are the Tungar made by the General Electric Co., and the Reetigon,
made by the Westinghouse Electric and Manufacturing Co. The Tungar
Rectifier is used extensively and will therefore be described in
detail.
The essential parts of a Tungar Rectifier are: A bulb, transformer,
reactance, and the enclosing case and equipment.
The bulb is the most important of these parts, since it does the
rectifying. It is a sort of check valve that permits current to flow
through the charging circuit in one direction only. In appearance the
bulb, see Figure 49, resembles somewhat an ordinary incandescent bulb.
In the bulb is a short tungsten filament wound in the form of a tight
spiral, and supported between two lead-in wires. Close to the filament
is a graphite disk which serves as one of the electrodes. Figure 50
shows the operating principle of the Tungar. "B" is the bulb,
containing the filament "F" and the graphite electrode "A." To serve
as a rectifier the bulb filament "F" must be heated, this being done
by the transformer "T." The battery is connected as shown, the
positive terminal directly to one side of the alternating current
supply, and the negative terminal to the graphite electrode "A."
To understand the action which takes place, assume an instant when
line wire C is positive. The current then flows through the battery,
through the rheostat and to the graphite electrode. The current then
flows through the are to the filament and to the negative side of the
line, as indicated by the arrows.
During the next half cycle when line wire D is positive, and C is
negative, current tends to flow through the bulb from the filament to
the graphite, but as the resistance offered to the flow of current in
this direction is very high, no current will flow through the bulb and
consequently none through the battery.
[Fig. 50 Illustration of Tungar "half-wave" rectifier]
[Fig. 51 Illustration of Tungar "full-wave" rectifier]
The rectifier shown in Figure 50 is a "half-wave" rectifier. That is,
only one-half of each alternating current wave passes through it to
the battery. If two bulbs are used, as shown ill Figure 51, each half
of the alternating current wave is used in charging the battery. To
trace the current through this rectifier assume an instant when line
wire C is positive. Current will then flow to the graphite electrode
of tube A, through the secondary winding of the transformer S to the
center tap, through the rheostat, to the positive battery terminal,
through the battery to the center of the primary transformer winding
P, and through part of the primary winding to D. When D is positive,
current will flow through tube B from the graphite electrode to the
filament, to the center of transformer winding S, through the rheostat
and battery to the center of transformer winding P, and through part
of this winding to line wire C. In the actual rectifiers the rheostat
shown in Figures 50 and 51 are not used, regulation being obtained
entirely by means of other windings.
From the foregoing description it will be seen that if the alternating
current supply should fail, the batteries cannot discharge into the
line, because in order to do so, they would have to heat up the
filament and send current through the bulb from the filament to the
graphite electrode. This the batteries cannot do, because the
connections are such that the battery cannot send a current through
the complete filament circuit and because, even if the batteries could
heat the filament they could not send a current from the filament to
the graphite, since current cannot flow in this direction.
As soon as the alternating line is made alive again, the batteries
will automatically start charging again. For these reasons night
charging with the Tungar is entirely feasible, and no attendant is
required to watch the batteries during the night. The Tungar Rectifier
is made in the following sizes:
A. Two Ampere Rectifier
Catalogue No. 195529
[Fig. 52. The Two Ampere Tungar Rectifier]
[Fig. 53 Internal wiring of the two ampere tungar rectifier]
This is the smallest Tungar made. Figure 52 shows the complete
rectifier. Figure 53 shows the internal wiring. This Tungar will
charge a 6 volt battery at two amperes, a 12 volt battery at one
ampere and eight cells at 0.75 ampere. It is suitable for charging a
lighting battery, or for a quick charge of a motorcycle or ignition
battery. It will also give a fairly good charge over night to a
starting battery. Another use for this rectifier is to connect it to a
run-down starting battery to prevent it from freezing over night. Of
course, a battery should not be allowed to run down during cold
weather, but if by chance a battery does run down, this Tungar will
prevent it from freezing during the night.
The two ampere Tungar is, of course, more suitable for the car owner
than for a garage or service station. It is also very suitable for
charging one Radio "A" battery. The two ampere Tungar is normally made
for operation on a sixty cycle circuit, at 115 volts. It may also be
obtained for operation on 25-30, 40-50, and 125-133 cycles alternating
supply line. See table on Page 130.
B. The One Battery Rectifier
Catalogue No. 219865
[Fig. 54. The One Battery Tungar Rectifier]
This Tungar will charge a 6 volt battery at five amperes, or a 12 volt
battery at three amperes. Figure 54 shows this Tungar, with part of
the casing cut away to show the internal parts.
To take care of variations in the voltage of the alternating current
supply from 100 to 130, a set of connections is provided which are
numbered 105, 115, and 125. For most supply voltages, the 115 volt tap
is used, for lower voltage the 105 volt tap is used, and for higher
voltage the 125 volt tap is used. This Tungar is designed for 60 cycle
circuits, but on special order it may be obtained for operation on
other frequencies.
This Tungar is most suitable for a car owner, is satisfactory for
charging a radio "A" battery, and a six volt starting and lighting
battery at one time.
C. The Two Battery Rectifier
Catalogue No. 195530
[Fig. 55. The Two Battery Tungar Rectifier]
This Tungar is shown in Figure 55, with part of the casing cut away to
show the internal parts. It was formerly sold to the car owner, but
the one battery Tungar is now recommended for the use of the car
owner. The two-battery Tungar is therefore recommended for the very
small service station, or for department stores for taking care of one
or two batteries. The four battery Tungar, which is the next one
described, is recommended in preference to the two-battery outfit
where there is the slightest possibility of having more than two
batteries to charge at one time.
The two-battery rectifier will charge two 6-volt batteries, or one
12-volt battery at six amperes, or one 18-volt battery at three
amperes. It has a double-pole fuse block mounted on the auto
transformer core, which has one fuse plug only. Figure 55 shows the
fuse plug in the position for charging a 6-volt battery. When it is
desired to charge a 12-volt battery or an 18-volt battery, the fuse is
removed from the first receptacle and is screwed into the second
receptacle.
[Fig. 56. The Four Battery Tungar Rectifier Complete]
The two-battery rectifier is designed to operate on a 115-volt,
60-cycle line, but oil special order may be obtained for operation on
25-30, 40-50, and 125-133 cycle lines.
D. The Four Battery Tungar
Catalogue No. 193191
This Tungar is shown complete in Figure 56. In Figure 57 the top has
been raised to show the internal parts. Figure 58 gives the internal
wiring connections for a four battery Tungar designed for operation on
a 115 volt line.
The four battery Tungar will charge from one to four 6 volt batteries
at 5 amperes or less. It is designed especially for garages having
very few batteries to charge. These garages generally charge their
boarders batteries rather than send them to a service station, and
seldom have more than four batteries to charge at one time. The four
battery Tungar is also suitable for the use of car dealers who wish to
keep the batteries on their cars in good shape, and is convenient for
preparing for service batteries as they come from the car manufacturer.
[Fig. 57. The Four Battery Tungar Rectifier, with Top Raised to Show
Internal Parts.]
The four battery Tungar is designed for operation on a 60-cycle line
at 115 or 230 volts. On special order this Tungar may be obtained for
operation on other frequencies.
E. The Ten Battery Rectifier
Catalogue No. 179492
This is the Tungar which is most popular in the service stations,
since it meets the charging requirements of the average shop better
than the smaller Tungars. It will charge from one to ten 6 volt
batteries, or the equivalent at six amperes or less. Where more than
ten batteries are generally to be charged at one time, two or more of
the ten battery Tungars should be used. Large service stations use as
many as ten of these Tungars.
[Fig. 58 Internal wiring of the four battery tungar rectifier]
The efficiency of the ten battery Tungar at full load is approximately
75 per cent, which compares favorably with that of a mercury-are
rectifier, or motor-generator of the same size. This makes the ten
battery Tungar a very desirable piece of apparatus for the service
station.
[Fig. 59 Complete 10-battery Tungar rectifier]
Figure 59 shows the complete ten battery Tungar, Figure 60 gives a
side view without the door to show the internal parts.
[Fig. 60 Side view, cross-section of 10-battery Tungar
rectifier]
Figure 61 shows the internal connections for use on a 115-volt A.C.
line and Figure 62 the internal connections for use on a 230-volt
line. This Tungar is made for a 60-cycle circuit, 25-30, 40-50, and
125-133 cycle circuits.
[Fig. 61 Internal wiring for the 10 battery Tungar rectifier
for operation on a 115 volts A.C. line]
[Fig. 62 Internal wiring for the 10 battery Tungar rectifier
for operation on a 230 volts A.C. line]
F. The Twenty Battery Tungar
Catalogue No. 221514
This Tungar will charge ten 6-volt batteries at 12 amperes, or twenty
6-volt batteries at six amperes. Figure 63 shows the complete
rectifier, and Figure 64 shows the rectifier with the side door open
to show the internal parts. This rectifier will do the work of two of
the ten battery Tungars. It is designed for operation on 60 cycles,
230-volts. On special order it may be obtained for operation on 115
volts and also for other frequencies.
The twenty battery Tungar uses two bulbs, each of which is the same as
that used in the ten battery Tungar, and has two charging circuits,
having an ammeter and regulating switch for each circuit. One snap
switch connects both circuits to the supply circuit. The two charging
circuits are regulated independently. For example, one circuit may be
regulated to three amperes while the other circuit is delivering six
amperes. It is also possible, by a system of connections to charge the
equivalent of three circuits. For instance, five batteries could be
charged at six amperes, five batteries at four amperes, and five
batteries at ten amperes. Other corresponding combinations are
possible also.
General Instructions and Information on Tungars
Life of Tungar Bulbs. The life of the Tungar Bulb is rated at 600 to
800 hours, but actually a bulb will give service for 1,200 to 3,000
hours if the user is careful not to overload the bulb by operating it
at more than the rated current.
[Fig. 63 The 20 battery Tungar rectifier]
[Fig. 64 Internal view of the 20 battery Tungar rectifier]
Instructions. Complete instructions are furnished with each Tungar
outfit, the following being those for the ten battery Tungar.
Installation
A Tungar should be installed in a clean, dry place in order to keep
the apparatus free from dirt and moisture. To avoid acid fumes, do not
place the Tungar directly over the batteries. These precautions will
prevent corrosion of the metal parts and liability of poor contacts.
Fasten the Tungar to a wall by four screws, if the wall is of wood, or
by four expansion bolts if it is made of brick or concrete.
Though the electrical connections of the outfit are very simple, it is
advisable (when installing the apparatus) to employ an experienced
wireman familiar with local requirements regarding wiring.
Line Connections
The two wires extending from the top of the Tungar should be connected
to the alternating current supply of the same voltage and frequency,
as stamped on the name plate attached to the front panel. These
connections should be not less than No. 12 B. & S. gauge wire and
should be firmly soldered to the copper lugs.
External fuses are recommended for the alternating-current circuit, as
follows:
With 115-volt line use 15-ampere capacity fuses.
With 230-volt line use 10 ampere capacity fuses.
One of the bulbs (Cat. No. 189049) should now be firmly screwed into
its socket. Squeeze the spring clip attached to the beaded cable and
slip this clip over the wire protruding from the top of the bulb. Do
not bend the wire.
Battery Connections
In making battery connections have the snap-switch in the "Off"
position.
The two wires extending from the bottom of the Tungar should be
connected to the batteries. The wire on the left, facing the front
panel, is marked + (positive) and the other wire - (negative). The
positive wire should be connected to the positive terminal of the
battery and the negative wire to the negative terminal.
The two flexible battery cables are sometimes connected directly to
the two wires projecting from the bottom of the Tungar. These cables
should be securely cleated to the wall about six inches below the
outfit. This arrangement will relieve the strain on the Tungar wires
when cables are changed to different batteries.
When two or more batteries are to be charged, they should be connected
in series. The positive wire of the Tungar should be connected to the
positive terminal of battery No. 1, the negative terminal of this
battery of the positive terminal of battery No. 2, the negative
terminal of battery No. 2 to the positive terminal of battery No. 3,
and so on, according to the number of batteries in circuit. Finally
the negative terminal of the last battery should be connected to the
negative wire from the Tungar.
Reverse connections on one battery is likely to damage the plates; and
reverse connections oil all the batteries will blow one or more fuses.
Operation
A Tungar is operated by means of a snap-switch in the upper left-hand
corner and a regulating switch in the center. Before starting the
apparatus, the regulating switch should be in the "low" position.
The Tungar is now ready to operate. Turn the snap-switch to the right
to the "On" position, and the bulb will light. Then turn the
regulating switch slowly to the right, and, as soon as the batteries
commence to charge, the needle on the ammeter will indicate the
charging current. This current may be adjusted to whatever value is
desired within the limits of the Tungar. The normal charging rate is
six amperes, but a current of as high as seven amperes may be obtained
without greatly reducing the life of the bulb. Higher charging rates
reduce its life to a considerable extent. Lower rates than normal (six
amperes) will increase the life of the bulb.
Turn the snap-switch to the "Off" position when the charging of one
battery or of all the batteries is completed; or when it is desired to
add more batteries to the line.
The Tungar should be operated only by the snap-switch and not by any
other external switch in either line or battery circuits.
When the snap-switch is turned, the batteries will be disconnected
from the supply line, and then they may be handled without danger of
shock.
Immediately after turning the snap-switch, move the regulating handle
back to the "Low" position. This prevents any damage to the bulb from
the dial switch being in an improper position for the number of
batteries next charged.
Troubles
If on turning on the alternating-current switch the bulb does not glow:
1. See whether the alternating-current supply is on.
2. Examine the supply line fuses. If these are blown, or are
defective, replace them with 15 ampere fuses for a 115-volt line or
with 10-ampere fuses for a 220-volt line.
3. Make sure that the bulb is screwed well into the socket.
4. Examine the contacts inside the socket. If they are tarnished or
dirty, clean them with sandpaper.
5. Try a new bulb, Cat. No. 189049. The old bulb may be defective.
If the bulb lights but no current shows on the ammeter:
1. Examine the connections to the batteries, and also the
connections between them. Most troubles are caused by imperfect
battery connections.
2. Examine the fuses inside the case. If these are blown or are
defective, replace them with 15 ampere fuses, Cat. No. 6335.
3. See that the clip is on the wire of the bulb.
4. The bulb may have a slow leak and not rectify. Try a new bulb,
Cat. No. 189049.
5. Have the switch arm make good contact on the regulating switch.
If the current on the ammeter is high and cannot be reduced:
1. The ammeter pointer may be sticking; tap it lightly with the
hand. The ammeter will not indicate the current correctly if the
pointer is not on the zero line when the Tungar is not operating.
The pointer may be easily reset by turning slightly the screw on
the lower part of the instrument.
2. Be sure that the batteries are not connected with reversed
polarity.
3. The alternating-current supply may be abnormally high. If only
one three-cell battery is being charged, and the
alternating-current supply is slightly high, then the current on
the ammeter may be high. The simplest remedy is to connect in
another battery or a small amount of resistance.
A spare bulb should always be kept on hand and should be tested for at
least one complete charge before being placed in reserve. All Tungar
bulbs are made as nearly perfect as possible, but occasionally one is
damaged in shipment. It may look perfect and yet not operate. For this
reason all bulbs should be tried out on receipt. If any bulb is found
defective, the tag which accompanies it should be filled out, and bulb
and tag should be returned to your dealer or to the nearest office of
the General Electric Company, transportation prepaid.
Tungar Rectifiers
(The following columns omitted from the table below: Catalog Numbers,
Dimensions, Net Weight, and Shipping Weight.)
Name
No. 6V Bats No. 12V Bats. DC Amps DC Volts AC Volts Freq.
------------- ------------- ------- -------- -------- -----
2 Amp. Tungar
1 (2 amps.) 1 (1 amps.) 1-2 7.5-15 115 60
2 Amp. Tungar
1 (2 amps.) 1 (1 amps.) 1-2 7.5-15 115 60
2 Amp. Tungar
1 (2 amps.) 1 (1 amps.) 1-2 7.5-15 115 40-50
2 Amp. Tungar
1 (2 amps.) 1 (1 amps.) 1-2 7.5-15 115 25-30
2 Amp. Tungar
1 (2 amps.) 1 (1 amps.) 1-2 7.5-15 115 125-133
1 Battery Tungar
1 (5 amps.) 1 (3 amps.) 1-5 7.5-15 115 60
2 Battery Tungar
2 (6 amps.) 1 (6 amps.) 1-6 7.5-15 115 60
2 Battery Tungar
2 (6 amps.) 1 (6 amps.) 1-6 7.5-15 115 40-50
2 Battery Tungar
2 (6 amps.) 1 (6 amps.) 1-6 7.5-15 115 25-30
2 Battery Tungar
2 (6 amps.) 1 (6 amps.) 1-6 7.5-15 115 125-130
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 115 60
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 115 40-50
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 115 25-30
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 115 125-133
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 230 60
4 Battery Tungar
4 (5 amps.) 2 (5 amps.) 1-5 7.5-30 230 40-50
10 Battery Tungar
10 5 1-6 7.5-75 115 60
10 Battery Tungar
10 5 1-6 7.5-75 115 40-50
10 Battery Tungar
10 5 1-6 7.5-75 115 25-30
10 Battery Tungar
10 5 1-6 7.5-75 115 125-133
10 Battery Tungar
10 5 1-6 7.5-75 230 60
10 Battery Tungar
10 5 1-6 7.5-75 230 40-50
20 Battery Tungar
10 (12A.)/
20 (6A.) 10 (6A.) 1-12 7.5-75 230 60
20 Battery Tungar
10 (12A.)/
20 (6A.) 10 (6A.) 1-12 7.5-75 230 40-50
20 Battery Tungar
10 (12A.)/
20 (6A.) 10 (6A.) 1-12 7.5-75 230 25-30
Bulb (all
4 Amp. Tung.)
--- --- --- --- --- ---
Bulb (all 10 and
12 Amp. Tung.)
--- --- --- --- --- ---
Bulb (all 2
Amp. Tung.)
--- --- --- --- --- ---
Bulb (all 1-2
Bat. Tung.)
--- --- --- --- --- ---
Mercury Arc Rectifier
The operation of the mercury are rectifier depends upon the fact that
a tube containing mercury vapor under a low pressure and provided with
two electrodes, one of mercury and the other of some other conductor,
offers a very high resistance to a current tending to pass through the
tube from the mercury electrode to the other electrode, but offers a
very low resistance to a current tending to pass through the tube in
the opposite direction. Current passes from the metallic electrode to
the mercury electrode through an are of mercury vapor which is
established in the tube by tilting it so the mercury bridges the gap
between the mercury and an auxiliary electrode just for an instant.
The absence of moving parts to got out of order is an advantage
possessed by this rectifier over the motor-generator. The charging
current from the rectifier cannot, however, be reduced to as low a
value as with the motor-generator, and this is a disadvantage. This
rectifier is therefore more suitable for larger shops, especially
where electric truck and pleasure cars are charged.
Mechanical Rectifiers
Mechanical rectifiers have a vibrating armature which opens and closes
the charging circuit. The circuit is closed during one half of each
alternating current cycle, and open during the next half cycle. The
circuit is thus closed as long as the alternating current is flowing
in the proper direction to charge the battery, and is open as long as
the alternating current is flowing in the reverse direction. These
rectifiers therefore charge the battery during half the time the
battery is on charge, this also being the case in some of the are
rectifiers.
The desired action is secured by a combination of a permanent magnet
and an electromagnet which is connected to the alternating current
supply. During half of the alternating current cycle, the alternating
current flowing through the winding of the electromagnet magnetizes
the electromagnet so that it strengthens the magnetism of the
permanent magnet, thus causing the vibrator arm to be drawn against
the magnet. The vibrator arm carries a contact which touches a
stationary contact point when the arm is drawn against the magnet,
thus closing the charging circuit.
During the next half of the alternating current cycle, or wave, the
current through the electromagnet coil is reversed, and the magnetism
of the electromagnet then weakens the magnetism of the permanent
magnet, and the vibrator arm is drawn away from the magnet and the
charging circuit is thus opened. During the next half of the
alternating current cycle the vibrator arm is again drawn against the
magnet, and so on, the contact points being closed and opened during
half of each alternating current cycle.
Mechanical rectifiers are operated from the secondary windings of
transformers which reduce the voltage of the alternating current line
to the voltage desired for charging. Each rectifier unit may have its
own complete transformer, or one large transformer may operate a
number of rectifier units by having its secondary, or low tension
winding divided into a number of sections, each of which operates one
rectifier.
The advantages of the mechanical rectifier are its simplicity,
cheapness and portability. This rectifier also has the advantage of
opening the charging circuit when the alternating current supply
fails, and starting again automatically when the line is made alive
again. Any desired number of independent units, each having its own
charging line, may be used. The charging current generally has a
maximum value of 6 amperes. Each rectifier unit is generally designed
to charge only one or two six volt batteries at one time.