Message text written by Geo Hahn
>1. The car is now negative ground. Because the radio is still + ground
and the ammeter reads backwards I suspect that someone may have simply
installed the battery the wrong way 'round. Am I correct that sometimes
this (just reversing the battery) can successfully polarize the starter
and generator for negative ground? I realize this is not the
recommended approach, I will do it properly when I change back to +
ground, but is there anything likely to have been damaged if the battery
was reversed without other preparations?
<
George, congratulations on your recent acquisition.
In answer to your question, yes I suppose it is possible that the generator
repolarized itself. It could be a rather traumatic event, however.
Consider the generator bootstrapping itself to -12 volts then the cutout
relay pulling in connecting this -12 volt output to the +12 volt battery.
If the contacts remain closed long enough the proper polarity could be
applied to the field long enough to repolarize it and everything will be
normal (except for a little extra pitting of the voltage regulator
contacts.
As far a damage goes, I would fear that the radio did not survive the
reverse polarity. It is a policy with me that anything battery powered
should be protected against damage if the battery is connected backwards
and, indeed, all of my designs will not sustain damage if so connected.
They may not function when hooked up backwards but once the battery is
reconnected it should function normally. Unfortunately, not everyone feels
the same way and many, many products possess such protection and if the
battery is connected backwards unhappy things happen.
Everything else on a stock TR4 is polarity insensitive.
Cheers and have fun with it.
Dave
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