QuestionI have a 1930 Model A and I've just got it running again after several years of neglect. I find the amp meter is pegged when running and extremely hot to the touch. Can my alternator be over charging ?
AnswerHeating of any electrical item means that more current is flowing through it than the current carrying parts are able to tolerate.
If the car has been modified, there is no way to diagnose it without examining what is actually installed. This is best done at an experienced automotive electrical repair shop. If the car does have an alternator, it has definitely been modified - and it could well be the case that the alternator is providing way more current than the rest of the electrical system was designed to tolerate.
Your car would originally have had a generator with a "cut-out" to control the amount of current provided by the generator when it was new.
If it has not been modified, it is possible that the "cut-out" has failed, thus causing the generator to provide too much current. Other symptoms of this would be abnormally bright headlights, and boiling of the water in the battery. If your car has those symptoms, you need to test or replace the cut-out device. The "cut-out" is an early type of voltage regulator which was common in cars of the early 30s. The cut-out is mounted on the generator, and is a small added on box or can with 2 or 3 wires going to it from the generator terminals.
With the original electrical system, those symptoms could also be due to poor (dirty or loose) connections at the terminals of the ammeter (if it is the terminals themselves that are hot), or excessive current flowing through the gauge.
It could also be caused by a missing or damaged shunt (a length of wire connected to both terminals of the ammeter to bypass most of the current away from the ammeter internal parts). Inspect the wires connected to the ammeter to see if there is one wire that connects to both terminals - if there is, make sure that wire is in good condition and that it's metal terminal ends are clean and tight. If there is no such wire, or if it appears to be in poor condition, you can replace it with a 2 foot long piece of #14 gauge copper wire, with soldered terminals on the ends, connected with one end of the wire on each ammeter terminal. This should eliminate the meter being pegged and the overheating.
Dick
