VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1926 Generator

I have noticed that my car seems to be drawing power from battery even when ignition was off. I thought maybe my ignition switch was acting up but would get to it when I could and for the meantime just disconnect battery cable when not in use. Started tracing wires and it appears the generator is grounding the system and getting warm. Question? None of the wires in the generator should be recieving ground(brushes, relay,windings)? What could be causing this?

When ignition is turned on relay activates.

Bobk

It sure sounds like the generator cut-out isn't cutting out. With the battery disconneted and everything turned off, see if there is continunity across the cut-out terminals. If the cut-out is working properly, an ohm meter should show infinite resistance. If the reading goes to zero, then the cut-out is faulty. I had a similar problem once. Burned up the generator and drained the battery. Live and learn.

Dan

Yep...it sounds like a defective cut-out to me as well.

I took generator apart and cleaned everything. It looks OK and wires are all connected. I hooked up volt meter, ground wire to ground on car and red to output wire on generator. I disconnected cutout relay. I ran car and no volts are being produced. Could the wires on the brushes be reversed? I have found many things in this cars's history put together wrong.
Relay may be OK. When I turn igniton switch the relay operates.
Any help would be appreciated.

Bobk

The cut-out rely should not operate when you turn the ignition on. The points in the cut-out should not close until the car is running and the generator reaches a certain RPM. Then the points should close allowing the current to flow from the generator to the battery.

So, Is it the volts from the generator that close the points or the battery.? Sounds like if it is the generator then maybe I have it wired backwards. The book shows I have it wired right.

Bobk

When then generator reaches a certain RPM the points in the cut-out will close. As we mentioned in earlier postings above, it sounds like your cut-out might be defective. Change the cut-out and see what happens.

The 6 volts the battery produces should not be enough to close the cutout. The cutout should need the higher voltage produced by the running generator to close.
A friend has suggested putting a diode in series in the circuit so that if the cutout fails you won't fry the generator. He promised to give one. Has anyone else tried this?

I have been modifying the cut-outs for years with diodes.

Same here...I have been doing the diode conversion on cut-outs for decades.

By the way, the points on the cut-out should close at around 6.7 volts and 650 to 750 RPM generator speed.

What size diode do you use and where is the best place to get them. Sound like a good modifaction for the cut out relay even on my 29 system.

Because of the way the cut-out is built battery voltage does not close the points. The electromagnetic coil that closes the pints is energized by the generator not the battery. That is how it keeps the battery from trying to motor the generator and running down.

Snyder's Antique Auto Parts in New Springfield, OH carries diodes for Model T's and Model A's. The one for the T is a negative ground and sells for about $6. Part number T-5055-DIO. I don't know what it is rated at, maybe 20 amps.

http://www.snydersantiqueauto.com

Dan

I have took apart generator and cleaned. It looks like nothing is wrong. When I start car I am getting no voltage from the generator ouput wire. What would be the likely problem and where can part be obtained like windings or armature? Does anyone know how to test windings or armature ?

Bobk

If you test the generator at the wire that comes out of the generator and no output, loosen the generator so you can remove the fan belt. Use a jumper wire to apply 6-volts to the wire going into the generator. It should run slowly like an electric motor. If it does not then the generator is bad. If you are not confident with the repair, there are two gentlemen in the G&D that specialise in electrical repair. Contact them for recommendations.

Did you polarize the generator first?

I did not but wondered about it. How do you do this? I have the generator at a Auto electric shop. They said they work on a lot of old tractors. They have not given me a report yet. So if they fix it I may need to polarize.

Bobk

Every time the generator is installed on the vehicle it should be polarized. With the ignition off, attach a jumper wire to the generator wire and touch the other end of the jumper wire to the wire that goes to the battery. You should have a spark. When it sparks the generator is polarized.