Need Some Generator Help

R

Richard D

Junior Member
First of all, I em extremely challenged when it comes to anything electrical. I have only the most basic grasp of the concepts. Here's the issue I'm dealing with. 1928 Model A coupe, pretty much all stock mechanically(as far as I know). It will not charge the battery. Somewhere along the way this car must have been converted to 12 volt. The contact points in the generator cut off appear to be burned up, we are getting 12.4 volts on the ARM(Armature?)side, and none on the BATT side. I have found a new cut out at Mac's Ford Parts, but a few things puzzle me: there are both positive ground and negative ground available, I don't understand the difference nor do I know what I need. Also, one is relay type, and the others are diode(I guess that is an upgrade?). Third, and probably not really an issue, my existing part has small capscrews hooding the wires, all the new parts have a spade connector on one side. I'm not sure which one I need.

http://www.macsautoparts.com/ford_model_a/catalogsearch/result/?q=generator+cut+out&x=0&y=0
 
The 6v model A generator will generate up to 32 volts when disattached from a battery and at high speed. 12V could be a number at idle speed.

Contact points could be your reason why. But any other reason you might not have current flow to your battery COULD be the reason - including the ground cable connecting the battery to your frame.

Model A is a positive ground. Battery plus goes to the frame. Different than modern cars but functionally no different.

You are probably NOT converted to 12 volts. A count of the number of cells of your battery should tell you for certain. Three cells = 6v system. Six cells = 12v system.

Diode or relay the function of the cutout is the same - to act as a "check valve" and allow current to flow in only one direction. Diodes have the advantage of reliability - but a disadvantage of "leakage." (meaning they present a small current drain continuously to the battery.) Relay has the advantage of originality - but that is about all. Well, maybe easily diagnosed if not working.

Sounds like you need to get your generator connected to your battery pronto. You can "jump" the terminals between in and out of the cutoff temporarily - but before you stop your engine, be sure to remove your jumper.

Let us know how this works for you.

Oh. Your "cap screw on both sides" would appear to be a replacement cutout. The "spade on one side" would have been used originally and the two fingers go under the insulated copper bolt/conductor protruding through the side of the generator. You may have a later generator if you don't see this - later generator had "wires" (or wire) coming out of the case to attach to the cutout.

Joe K
 
We have a '31 also, has been converted to alternator(which I do not want to do on the '28). These cars belong to a sponsor of ours, who alsoThere is a 12 volt battery, but maybe the generator is not converted to 12 volt, it is just reading as such at idle. Can I use a 12 volt battery with a 6 volt generator?
 
Richard D said:
We have a '31 also, has been converted to alternator(which I do not want to do on the '28). These cars belong to a sponsor of ours, who alsoThere is a 12 volt battery, but maybe the generator is not converted to 12 volt, it is just reading as such at idle. Can I use a 12 volt battery with a 6 volt generator?
Click to expand...
YES, Purdy will be right here to tell you how. I've never done it, myself, the Dog might have done it before I rescued him????
Bill W.
 
Can I use a 12 volt battery with a 6 volt generator?
Click to expand...

Yes, we did exactly that to a Ford 9N at the farm and with the recommendation of our local generator rewinding shop. It should work very fine as it stands.

And we ran the original starter without change on that 12v as well. It started the tractor VERY smartly. Some here advise changing the starter to reduce risk of breaking the gear.

Best arrangement for the generator would be to convert it to a voltage regulator. Tom Weisenberg of this forum sells the kit and will advise if he sees this thread.

Ford's system of "driver matching" generation to power need was not even state of the art in 1931 - but adequate for what he wanted to sell. Voltage regulators do it MUCH better than any driver can do - and extend the life of your battery in the process.

Good luck on solving your issues. Definitely check your connection one by one between the generator outlet and the car frame. Also check the generator is grounded itself.

Joe K
 
I only make EVR's for 6 volts positive ground. You can use the stock generator as is to charge the 12 volt battery, or you can buy the can cutout/regulator from John Regan for 12 volt negative ground.
 
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