Checking generator output

[Andrew]

Can someone knowledgeable talk me through testing the output of a Bosch generator? In all honesty, this is for a 1965 6V VW, not an Alfa, but the process ought to be the same.

My charge light stays on; I have 6.06+- V at the battery that does not vary with RPM. Brand new 6V battery that starts the car fine. I had a local shop test the gen and they said it was fine. Based on that, I bought a new regulator, installed and polarized it per the instructions, but I still get no additional charge at the battery. So I wonder if the gen is really any good.

There are three leads coming out of the gen, two going to one connection, the other going to the other connection, on the reg. I read in an old manual that you disconnect the reg and put your voltmeter on one output lead and the other to ground, but I'm not sure I did it right.

Thanks for any help here.

Andrew

[Alfacliff]

the larger terminal is the armature, or output lead. the other is the field. if you disconnect the wires from each, and tie the field to the armature, the voltage output will go up when the engine rpm increases.
a good test without disconneting anything is to start the car and watch the voltage on the battery, it should increase as you speed the engine up. the generators do not put out current at lower rpm like alternators do. as the engine runs up from idle, the voltage should increase a bit. 6.8 to 7.0 volts is about normal for those. also, turn the lights on, the voltage should not drop much with the engine above idle.
cliff

[Andrew]

I tried that, and said above that my voltage at the battery with the engine running does not vary at all regardless of rpm (even high up, for a VW). That is, with a voltmeter on the battery, there is no voltage change, and the charge light never goes out, regardless of rpm. So nothing is getting through the reg to the bat, but I don't know if the reg or the gen is the problem.

How do I tie the field to the armature? Do I understand correctly that if I do that I should keep the rpm low so as not to overstress the generator?

Thanks

Andrew

[Alfacliff]

jumper the armature wire to the field wire. the field is the control voltage input to the generator, the more current into the field, the more output from the armature.
cliff

[Andrew]

So I connect the two main leads coming out of the gen? Then hook the voltmeter positive to them, and the voltmeter negative to ground, to see what I'm getting?

Andrew

[Alfacliff]

Yes, thats the way.
cliff

[Andrew]

Thanks; I'll try.
Andrew

[Slash]

Check out this site: Rob & Dave's.

[Andrew]

Yowza. Thanks Ron.
Andrew