The Panhead & Flathead Site

Hi,
any tips how to test and measure generator output easy way.
I have removed it off the engine (because engine is under repair) and run it with electric drill to see how much the voltage output between A and F connectors.
I only get 0.5V output voltage this way.
Do I need to connect generator to voltage regulator and battery to get real output voltage measuremnts from generator ?
Or how to do proper testing ?

Generator is two brush 12V

you should connect it to a battery and a regulator. You should measure very little, if any, voltage between A & F terminals the way you had it.

Hook it up the way it is shown in a wiring diagram fo ryour year bike/equipment. Don;t forget the "ghround" connectioons that would normaly be done thru the bike frame.

you could hook the + side to armature terminal and neg lead to the generator body then with it turning ground the F terminal.

Generators need electricity to make electricity. Unless you supply battery voltage to the field coils, which energizes them and creates the magnetic field around the spinning armature, you won't get any output. You will not get any output from the field terminal, ever, it is for putting power INTO the fields.

Try this. There should be enough residual magnatism in the iron pole shoes to start the generating process. Connect the battery and field posts together. Connect your volt meter between the battery terminal (which is now also connected to the field terminal) and the case of the generator (ground). Now you can spin the generator with your drill or some other method, after it spins up and stabilizes for a short time you should see full voltage output on your meter. Make sure you spin it in the right direction.

When doing this you have to remember that you have no regulator in this simple circuit so you don't want to do this for very long. The faster you spin it, the more power it will make. The more power it makes, and feeds back into the field circuit, the more power it will make, etc., etc., until it melts itself down. But a quick, short, spin will tell you if it works.

mike

I'm pretty sure "rrhawg" has it right-one side of the filed in the 2-brush generator is already tied to the "A" lead internally, so grounding the F terminal(the other side of the filed) is the way to go to test the generator.

Tying A to F will only short out the field coils entirely.

See:

oops, I was thinking 3-brush. Thanks rrhawg for waking me up.

Everything as I explained above except tie the field terminal together with the ground for your 2-brush unit. Like I said, don't run it very long like this without a regulator in the circuit.

mike

you beat me to it Andy, thanks

Thank you very much for the good advice.
That I'll try next to check my generator.

AAAAARRRGGGGHHHH !!!!

I think I lose my mind with this 12V generator problem, dammit !

Lets go step by step:
- I made a wire connections without voltage requlator as in picture below.

-and turn the generator with electric drill anticlockwise
-voltage meter measured results from 0-16 volts and even more if I put more revs in drill
So, this result sounds ok to me and tells that generator should be ok.

But then I conncted voltage regulator (as in picture) to generator connections according instructions from regulator.
-Red to Battery, Green to Fied and Black to Armature.
-grounding for the regulator is get from the base when bolt it to generator
-Battery negative pole is conncted to generator frame
-then also battery wires as in picture below:

When I connect red wire to battery positive pole, voltage measurement starts to drop down and generator somehow gets stuck ,it is very hard to turn the generator axle ???

Questions:
-Is this connection correct way to connect wires to test generator with the voltage regulator and battery ???
-And is engine rotating generator anticlockwise, look it from mounting pin bolt side ?

It should get a LOT harder to turn the generator when it is actually charging a battery.

I don;tknow what kind of torque a running, charging geberator takes to turn it, but I wouldn't be surpeised if any old electric drill motor had a problem turning it.

Get something that will keep up the generator speed while attached to the regulator/battery,a nd I bet it starts to charge.

don't get too frustrated just yet.

i do not think a drill would have enough torque to spin a generator.

i have been experimenting with a 1/3 horse power 120v electric motor to test generators and it WILL NOT spin either a 32e or a model 52 fast enough to make even 6 volts! and that is with no load!



yes and yes!

john

JohnHD is correct, I realized after a few tries with AC drills that the generator spins very fast on the engine. I never found any RPM specs for a 32E but I could get just a few amps withy a drill but on the engine it was fine.

This case can be closed
I redo all the wiring from field coils and replace connectors and check brushes. Then I get generator out put voltage work just fine.

But then I spend a lot of hours to check what is wrong with my new regulator wiring.
I tryed my friends electrical regulator and managed to get that working with my generator.
Then I put my new voltage regulator in use and find out that cable connections was instructed WRONGLY in retailers instructions.
They instruction was written this way:
Red wire to battery positive
Green wire to Field
Black wire to Armature

They were totally wrong in resellers instructions !!!

Correct way is like this and this way it only can work and it charges battery as it should:
Red wire to Armature
Green wire to Field
Black wire to Battery positive

How the hell they can do that kind of mistake ? And I have send some e-mails to this company to re-check their instructions.
Lets wait that answer....

But thanks to you fellows who gave me good ideas where to start trouble shooting

Now it's my turn for generator problems.

I have a Harley Davidson 65A 12V Generator. I followed the test procedure in the Clymer's manual for measuring current. The generator puts out about 12 amps at 2000-2500 RPM.

Since that was the genny output with no voltage applied to the Field, I tried another test. I reconnected everything including the relay (brand new, 12V, solidstate) so there should be 12V on the field coil. I fired the bike up and the regulator light flickered when the RPMs were low, but came ON steady when I raised it up to ~2000 RPM.

What the heck?

Can I buy a clue?

did you polarize it?

Do you have a battery hooked up?