The application of secondary or storage batteries to electrical
traction has been accomplished in a number of cities, with a varying
amount of success. Roads equipped by batteries have now been
sufficiently long in operation to allow us to draw some conclusions as
to the practical results obtained and what is possible in the near
future. The advantages which have been demonstrated on Madison Avenue,
in New York; Dubuque, Iowa; Washington, D.C., and elsewhere, may be
summarized as follows:
_First_. The independent feature of the system. The cars independent
of each other, and free from drawbacks of broken trolley wires;
temporary stoppages at the power station; the grounding of one motor
affecting other motors, and sudden and severe strains upon the
machinery at the power station, such as frequently occur in direct
systems; the absence of all street structures and repairs to the same,
and the loss by grounds and leakages, are also very considerable
advantages, both as to economy and satisfactory operation.
_Second_. The comparatively small space required for the power
station. Each car being provided with two or more sets of batteries,
the same can be charged at a uniform rate without undue strain on the
machinery of the power station, and as it can be done more rapidly
than the discharge required for the operation of the motors, a less
amount of general machinery is necessary for a given amount of work.
Another and important advantage of the system is the low pressure of
the current used to supply the motors, and the consequent increased
durability of the motor, and practically absolute safety to life from
electrical shock.
It has been demonstrated also that the cars can be easily handled in
the street; run at any desired speed, and reversed with far more
safety to the armature of the motor than in the direct system. The
increased weight requires simply more brake leverage.
The modern battery, improved in many of its details during the last
year, is still an unknown quantity as to durability. There is the same
doubt concerning this as there was at the time incandescent lamps were
first introduced. At that time some phenomenal records were made by
lamps grouped with other lamps.
Similarly, some plates appeared to be almost indestructible, while
others, made practically in the same manner, deteriorate within a very
short time. It is, consequently, very difficult to exactly and fairly
place a limit on the life of the positive plates as yet. Speaking
simply from observation of a large number of plates of various kinds,
I am inclined to put the limit at about eight months; though it is
claimed by some of the more prominent manufacturers--and undoubtedly
it is true in special cases--that entire elements have lasted ten
months, and even longer.
It must be remembered, however, that the jolting and handling to which
these batteries are subjected, in traction work, increases the
tendency to disintegrate, buckle and short circuit, and that the
record for durability for this application can never be the same as
for stationary work. A serious inconvenience to the use of batteries
in traction work is the necessary presence of the liquid in the jars.
This causes the whole equipment to be somewhat cumbersome, and unless
arranged with great care, and with a variety of devices lately
designed, a source of considerable annoyance.
The connections between the plates, which formerly gave so much
trouble by breaking off, have been perfected so as to prevent this
difficulty, and the shape of the jars has been designed to prevent the
spilling of the acid while the car is running. The car seats are now
practically hermetically sealed, so that the escaping gases are not
offensive to the passengers.
The handling of the batteries is an exceedingly important
consideration. Many devices have been invented to render this easy and
cheap. I have witnessed the changing of batteries in a car, one set
being taken out and a charged set replaced by four men in the short
space of three minutes. This is accomplished by electrical elevators,
which move the batteries opposite the car, and upon the platforms of
which the discharged elements are again charged.
The general conclusions which the year's experience and progress have
afforded us an opportunity to make may be summarized as follows:
Storage battery cars are as yet applicable only to those roads which
are practically level; where the direct system cannot be used, and
where cable traction cannot be used; and applicable to those roads
only at about the same cost as horse traction.
I feel justified in making this statement in view of the guarantees
which some of the more prominent manufacturers of batteries are
willing to enter into, and which practically insure the customer
against loss due to the deterioration of plates: leaving the question
of the responsibility of the company the only one for him to look
into.
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