Ammunition Hoist, Electric.
An apparatus for use on ships for hoisting ammunition to the guns by an
electric elevator. The characteristic feature of it is that a constant
motion of the switch or handle is required to keep it in action. If the
operator is shot so as to be incapacitated from taking charge of the
switch, the hoist stops until another is assigned to it.
Amperage.
Current intensity expressed in amperes, as an amperage of ten amperes.
Ampere.
The practical unit of electric current strength. It is the measure of
the current produced by an electro-motive force of one volt through a
resistance of one ohm. In electric quantity it is the rate of one
coulomb per second. It is one-tenth the absolute C. G. S. unit of
current strength. Its best analogy is derived from water. Assuming the
electric current to be represented by a current of water, the pressure,
head, or descent producing such current would be the electro-motive
force. The current might be measured in gallons (or other unit) passed
per second. In the analogy these gallons would be coulombs. But it might
be measured by reference to a standard stream, as for instance, the
stream which would pass through a hole an inch square under a given
head, say six inches of water. This unit is the miner's inch, and is the
exact analogy of the ampere. A current of water may flow at the rate of
so many miner's inches, just as a current of electricity may flow at the
rate of so many amperes. In neither case it will be noted is there any
reference to time. "An ampere per second" is a redundant expression, and
means no more than "an ampere"; an "ampere-second," on the other hand,
is a coulomb. The number of coulombs passed per second gives the amperes
of current.
For value of ampere, see Coulomb.
[Transcriber's note: The SI definition of an ampere: A current in two
straight parallel conductors of infinite length and negligible
cross-section, 1 metre apart in vacuum, would produce a force equal to
2E-7 newton per metre of length.]
Fig. 13. THE MINER'S INCH AS AN ANALOGY FOR THE AMPERE.