polarize generator?

D

donQ

Senior Member
To polarize a generator that uses an external regulator, you momentarily disconnect the field wire at the regulator and touch it to the battery terminal. Do you lift the third brush and then touch that to a battery source to polarize the Model A generator, or some other procedure? The model A generator I just bought has good brushes and runs great as a motor on the bench with quiet bearings. Is there anything else I should do prior to putting it on an engine?
donQ
 
The A generator doesn't normally use a regulator and if it motors it may not need to be polarized. With a standard cutout [non-diode]if polarizing is needed just jump across the cutout terminals for a nano-second.
 
Random thought: since you say that when you motor the generator it becomes polarized; What would happen if you were to hook it up backwards so to speak so its motoring opposite of what the engine would be turning it?

Once the engine is running does it polarize the other way?
 
SeaSlugs said:
Random thought: since you say that when you motor the generator it becomes polarized; What would happen if you were to hook it up backwards so to speak so its motoring opposite of what the engine would be turning it?

Once the engine is running does it polarize the other way?
Click to expand...

You can't make the generator run backwards unless you switch the feed and ground on the field windings. If you connect the battery with negative ground but polarized the generator on the bench with positive ground, you stand a chance of messing something up. Best to be sure and polarize the generator just before you start the engine, if this is the first time the generator is reinstalled.

And to answer an earlier question, no, you do not lift the field brush.
In fact, if you are using an external voltage regulator, you usually don't have a field brush. I'm thinking now of the 40's and 50's generators, if that's what you have.
 
Keep in mind it the generator is polarized differently than the car you will effectively put the generator in series with respect to the car. If you motor it as neg ground and put it in a positive grd car that would be a bad thing.
 
I think 30 coupe gave me the information I need. I don't have a regulator with this generator, it has the standard model A cut out cut out and it is positive ground.
Thanks for your input.
donQ
 
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