Clark writes;
>I would expect the major current in a short circuit would come from the
>battery, capacity hundreds of amps, not the alternator.
Depending on the internal resistance of the battery and the duration of the
short, you will see the battery capable of providing a very large surge of
initial current. There will be a significant voltage drop through the batterys'
internal resistance which will increase as time passes and the battery heats up
inside. As the battery terminal voltage droops, your alternator is going to
dutifully help the battery along so while the battery alone might be able to
sustain 100 amps or so for the duration of a long short, your alternator is
going to add another 50 amps or so until the wires fuse. Certainly a
significant contribution. This is assuming a circuit without fuses such as the
starter, anti run on valve or some others fed through "brown" wires (at least
BL's color code in the Spitfire for unprotected circuits). So the "majority" of
current is not an order of magnitude, but a "simple majority" sort of like our
Congress which generates a lot of heat but is limited by its own internal
resistance and consists of "simple majorities" most of the time. In fact, even
on an overwhelming vote, it is argueable that the majority is still very simple
:>) :>) :>) :>) but enough politics on our otherwise PC list.
regards, John Pratchios
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