6 volt alternator problem
 

Me again guys I have a 6 volt positive ground alternator and I'm pretty sure it isn't working. Before letting the tudor sit for 5 years I can't get the alternator to work. I always had to Rev the engine up a little bit to excite the fields to show a positive change on my amp meter I have a reproduction 6v horn and it always sounded sick and would not aooga till I reved the engine up which would be correct for a self excited alternator. I think? But it started before I parked it not showing a output on amp meter. I have tried to excite the fields with a jumper wire but no go so I thick the alternator is dead in the water. Question is should I buy a rebuild kit that you can get for a 12v alternator that changes a 12v to a 6v positive ground since I already have a alternator already set up for the 6v positive ground or just buy another brand new 6v positive ground alternator that's good go? Is there anything else that the convertion partr not make it work again? Thanks Robert

Re: 6 volt alternator problem
 

You said you did try to excite the field, but not sure if this is the same: The single pole 6-volt alternators will loose their magnetic flux after sitting for a long period of time. Easy fix. If it is a Nu-Rex, there is a rubber plug covering two pins. With the car running, simply ground pin #1 for a second or so using some sort of jumper wire. That should restore its flux and as good as new. Probably any alternator using the S-10 knock-off alternator will do the same. Try that. Those were the instructions I got from Nu-Rex after I had mine sitting for a year being restored.

Re: 6 volt alternator problem
 

Pin 1 is closer to the output post. Just place a small screwdriver blade between pin 1 and the housing (positive) for a second.

Re: 6 volt alternator problem
 

Thanks guys thats what I tried put a jumper wire from the first pin then to the housing for a little bit with engine running plus checked wires to make sure contacts were good but everything seemed to be OK it just didn't excite the magnetic field. After trying several times it never did show any difference on amp meter and also hooked a multmeter no difference car off or running showing 6.20 on meter. So not sure what to do. Robert

Re: 6 volt alternator problem
 

You could try a good jumper from battery + to the alternator case, may or may not help, but worth a try. I've heard that those alternators need to be well grounded.

Re: 6 volt alternator problem
 

Another option is to take it to a good alternator shop.

Re: 6 volt alternator problem
 

Those are hard to find these days. Too cheap to just swap it out (12V).

https://alternatorparts.com/6-volt-a...its-parts.html is a good source for diy or buy outright.

Try replacing the regulator first.

Re: 6 volt alternator problem
 

I had the same problem after my A sat for a long period of time due to COVID. I took it to an auto electric shop for a checkup. They put it on a bench tester and really revved it up. He was able to excite the alternator and get it going again. He said over time it had lost its magnetic field. I put the alternator back on the car and no problems since. It is possible your regulator died but not too probable.

Re: 6 volt alternator problem
 

If you don't mind doing some DIY work on it, the overhaul/conversion kits are available for the GM10si type alternators. The kit includes all that in needed for a 6-volt positive ground alternator conversion or overhaul.
https://www.ebay.com/itm/190696606664

These alternators are used on old tractors as well as antique cars so there are a lot of them around. This kit may be available from other sources for a better price. Just make sure it is for 6-volt positive ground. The kits are available in a lot of different applications and voltages.