Genorator vs Alternator

Beacher425 · Post by **Beacher425** » Fri May 28, 2010 9:33 am

I just bought a 1955 M38a1 that has the generator and regulator removed and an altermator installed. It reads on the unit as a 12v alternator. The starter is original 24v and it still has the 2 batteries in series installed. Looks like lights are 24v. Would it be easier to just complete the 12v changeover, or to return to 24v. If I return to 24v, does a 24v alternator exist? At the sale the jeep started and ran ok.

Thanks
Jeff
SC

MODIFIED · Post by **MODIFIED** » Fri May 28, 2010 11:44 am

what is you intended use with the vehicle, i.e; sunday drives, restoration, trails, primary driver, shows ?

I think if your jeep possess most of the 24 volt components keep it 24v..

check the following :
STARTER
GENERATOR
gen cable
VOLTAGE REG
DISTRIBUTOR
igniton cables
LAMP BULB
GAUGES

Post by **wesk** » Fri May 28, 2010 8:31 pm

I don't see how the 12 volt alternator can be functioning with the two batteries in series at 24Volts. Are you sure there's not a relay for converting to series for start and parallel for run?

Beacher425 · Post by **Beacher425** » Tue Jun 01, 2010 11:44 pm

I delayed posting so i could reexamine the jeep and the alternator is a 12V Delco. I see only 1 wire extending from it to the starter.

I plan on getting it running and using it for occasional drives around town and light offroad on some land I own. Overtime I will have the subcomponants overhauled and eventually down to the frame. The jeep is in such good shape now, i don't feel it neccessary to take it all the way down to the frame now. I would like it to be a "rolling restoration" that my kids and I can do peicemeal.

Jeff

Post by **wesk** » Wed Jun 02, 2010 7:45 am

If your batteries are in series (pos-neg-pos-neg) they will produce 24 volts which will work with your starter but will quickly burn up the internal regulator in a 12 volt alternator.

This means there are only the following possibilities:

1-The alternator's internal regulator is burned out and it is not producing voltage anymore.
2-The alternator has been converted to 24 volts.
3-There's a hidden dual voltage starting relay that starts on 24 volt and operates on 12 volt.
4-You batteries are not in series but are actually parallel (pos-pos) and (neg-neg) producing only 12 volts. (12 volts will turn a 24 volt starter slow).
5-Starter has been converted to 12 volt.

A few simple tests to determine what you really have:

1-Connect a voltmeter pos to the starter switch terminal with the battery pos cable on it. Connect the meter neg to the block or frame.

If it reads 12 volts you have batteries connected parallel. If it reads 24 volts you have batteries connected in series.

2-Start the engine and accelerate it to about 2,000 RPM.

If you had 24 volt on the batteries then it should now read 27.5 to 28.5 volts.
If you had 12 volts on the batteries then it should read 13.0 to 14.5 volts.

Beacher425 · Post by **Beacher425** » Wed Jun 02, 2010 9:08 am

Thanks! I will follow these and let you know what happens.

Beacher425 · Post by **Beacher425** » Tue Jul 27, 2010 7:27 am

Looks like the Alternator was a 24v after all. In disassebling the Jeep for a frame of restoration, on the under side of the alternator was "24v" painted on it. So I believe that it is a rebuilt alt ov 24v but in a shell of a 12v. We will see when it is all back together. Everything else coming off the jeep is 24v.