12 V generator

I replaced the generator on my 8N with a 12v Autolite generator pirated from a 1954 Chrysler.I just had it serviced by the local auto electric shop and
was advised that the voltage regulator was not usable. I sourced a NOS Prestolite voltage regulator but before I install it I need to know how to bench
test it. If I set it up to spin with an electric motor do I connect an ammeter to the battery terminal on the regulator directly to a battery polarize it and
test that way? I will wait to hear from one of the experts on the forum, TIA. Sam.

A 1954 Chrysler would have been 6V. Unless it had been upgraded at some point.

Thanks for the correction, I got confused because the first Buick v8 was 12v while the straight 8 was still 6V. The generator I have must be later
because it is 12 v.

One (among others such as voltage and polarity) reason the old VR may not be useable is if it was for a Class A Charging System (like the Ford may well have been unless it got changed) but the new Genny may be a Class B ???? I DONT KNOW SITTING HERE THINGS GET MODIFIED OVER THE YEARS. BOTH the genny and VR need to be matched for Class A or B as well as voltage, current and polarity. You have to get the correct Genny and matching VR for the battery (Class A or B, Voltage, Polarity) before anything

Before any start up I would POLARIZE the genny to match the battery polarity, be its POS or NEG Ground

Sure you can use a motor to spin the genny to check it before installation, or else instead of using a motor let the tractor spin it AFTER insuring the genny and VR are properly matched (Class A or B,,,,,,,Polarity,,,,,,,,Voltage),,,,,,,,,,, Polarize the Genny,,,,,,Wire up the Genny, VR and ammeter correctly, start the tractor and see if battery is charging or not IE see if its voltage rises as RPM increases and it produces Pos charging current INTO the battery versus Neg discharging current OUT OF the battery.

You ask do I connect an ammeter to the battery terminal on the regulator directly to a battery polarize it and
test that way?

You would wire the VR's BAT terminal to the LOAD side of an ammeter, ammeters other SUPPLY side to the Battery, VR's FLD terminal to Gennys FLD post,,VR's GEN/ARM terminal to Gennys ARM post,,Battery ground to VR case ground and Gennys case/frame ground

John T

54 Crown Imperial was 12V.

(quoted from post at 21:16:01 02/14/22) 54 Crown Imperial was 12V.

Click to expand...

Yes, apparently so. I stand corrected. He may have a 12V generator from a '54 Crown Imperial.

After some googling I found that '53 to '55 Crown Imperials were in fact [b:55f1384b23]12V POS ground[/b:55f1384b23]. Changed to NEG ground in '56 when all Chrysler products went to 12V NEG ground.


How common were Crown Imperials compared to the rest of the Chrysler line though? I can't find production numbers.





This post was edited by Carlmac 369 on 02/14/2022 at 05:48 pm.

You got your answer below. My first 12 conversion project was on a 46 JD A. I took a system off a junked 57 Chevrolet pickup. Having no idea how it all worked I removed the generator and regulator from the truck complete with the wiring and installed it on the A. It worked perfectly for years.