Over voltage.

[Cope]

I noticed my volt gauge is droppng so I got out the meter. I'm seeing 36 volts at the pin on the alt. I replaced the V.R. with no change.
I' thinking the fuse is blown hence the droppig voltage but I don' want to replace the fuse until I can figure out the issue.

Thanks for the help.

 

[67Dart273]

HOLY CRAP!! Don't run it that way or at the least, unplug the VR

This sounds like an OPEN in the charge path/ circuit to the battery. Stock wiring? Bypassed ammeter?

The following SHOULD NOT apply or else the following may have caused the open: (or else battery would also be high, very high V)

Or a bad VR causing full charge OR shorted field terminal at the alternator

Bad wire terminal, bad bulkhead connector terminal(s) failed harness "welded splice"

Should not be bad terminals at the ammeter because you would have NO power (no lights no nothing)

Check the alternator.......remove both field wires, check both field terminals to ground. should be OPEN AKA infinity

If none of the above fixes it, CHECK that the VR IS GROUNDED, and if that is OK replace the VR

 

[Cope]

The car has no bulkhead or amp meter.
It's a race car with all new wire.

I don't think it's the VR as the old one was doing the same thing.

What setting should I use to check the field, ohms?

I do have a spare alt I could try.

 

[67Dart273]

Post a photo or the brand / model of your meter.

You want a fairly low ohms scale, like 200 ohms. Short the probes to test it should show close to zero or a few tenths. With the probes connected to "nothing" that is the infinity reading. Should show that same reading when connected to either field and to the alternator case (ground)

 

[toolmanmike]

Post a photo or the brand / model of your meter.

You want a fairly low ohms scale, like 200 ohms. Short the probes to test it should show close to zero or a few tenths. With the probes connected to "nothing" that is the infinity reading. Should show that same reading when connected to either field and to the alternator case (ground)

A alternator can't charge that high unless the diodes are out. Correct? AC volts? What's full field DC output? 18 volts or so?

 

[Killer6]

Well, lets start off with some specifics, what alt./reg./system are You running? I can't say I've ever seen a stock Mopar alt over 21 Volts, and that was a later model vehicle.

 

[KitCarlson]

I think an alternator can put out up to 50V, if the field is driven directly from the alternator output, and not connected to battery load. As the alternator voltage increases, so does the field, a runaway condition, only limited by magnetic saturation. Remnant magnetism in rotor starts the process.

It is true with battery connected the voltage may only reach 21V. The battery impedance is low, and an the impedance of the alternator limits the source voltage.

Making a guess based on lack of information... wiring problems.