Packard Forum Index » Post-War (1946-54)

I have had this same question. Since it does not function as a volt meter, I just call it an ammeter. Close enough!!

Very generally, a volt meter would connect to a power source and ground (typically) while an ammeter connects inline between the source and load as it does on the Packard gauge. It IS an ammeter even if it is not calibrated or even incremented to give actual measurements in amps.

Anyway, great test procedures were outlined here that I will find quite handy when working on my cars as this is the stuff that 30 or 40 years of not working on them has made me forget!

Or to put it another way, connect voltmeters in parallel and ammeters in series.

The ammeter on my 740 registers charge, but very low compared to the specs. I bought a Model A ammeter for $15, temporarily connected it inline and found the actual generator output was actually set too high. I adjusted the third brush to set the correct amperage. Now I know that my dash ammeter registers only about 1/3 the actual charging rate. I wonder if the dash meter can be adjusted somehow.

I ran the test by grounding the field coil temporarily. The "genny" is hot! The meter pegged. So, cursing the voltage regulator, quietly.
Another factor is: I did put in a 6v Optima. As the voltage regulator is mechanical, I thought the Optima would not be an issue. Was I right??
Cleaning the points tomorrow...what saint should I address in my prayers?? A powerful heathen saint would suit just as well....

Just for something to do check the nuts on the back of the ammeter for tightness. Probably not the issue but if I remember, another poster had poor charging issues, changed several regulators and finally traced the problem to a bad connection at the ammeter. Once that was fixed the poor charging and regulator changing went away.

A good thing to try...I am assuming I need to remove the instrument board? Any info? Is anything published?

Shouldn't need to disassemble anything as the nuts are in the open but the area is a bit congested with switches and mounting brackets nearby so you may need to bend in places not accustomed to bending. Possibly the wiring loom could hinder access too but probably easier access to terminals than getting to the ign switch. Both terminals are hot all the time so be sure and disconnect the battery. Probably not the issue but a quick check of their tightness wouldn't hurt.

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The car was rewired so congested under there. But, as I do yoga twice a week, I can get under there!!!

Thanks!!

If you have a decent voltmeter measure the voltage across the battery with the engine running. The generator should get it up to about 7 to 7.5 volts even with the lights on.
fast idle.

Jim