The Panhead & Flathead Site

what is the easiest way to check a 12V generator (model 65A) outside the bike.
I can run the generator as a motor by jumpering the A and F terminals and put 12V to it (and ground to the housing). Runs regular.
Looks OK so far.
When I spin the generator (by using a beltdrive on a drilling machine) it only outputs 3-4 Volts.
Checked field coils, no short circuit, 2 amps in series on 12V supply which is OK according to HD manuals.
To my opinion armature looks OK, mica cut etc. No signs of damage or burned. I don't have a growler to check.
Any ideas??

ground the field and retry your belt drive test.

john

Try this site..

www.cycleelectricinc.com

Drop down to Tech...

George in Germany

Tried this but no luck.
I got 3-4 Volt on the A terminal and 0 on the F terminal (before grounding of course!) Jumpering A-F results also in 3-4 Volt against the housing.

Does anybody have a drawing/sketch of the internal wiring from terminals to field coil and armature back to terminals to be 100% I didn't make any mistakes here.

http://www.hydra-glide.com/phpBB3/viewtopic.php?f=67&t=4286

or this one

http://www.hydra-glide.com/phpBB3/viewtopic.php?f=62&t=1418

Thanks Panhead,

the drawing is for a 3 brush, I had this drawing already for my liberator.
I can't seem to find one for a 2 brush.
Would be OK just to describe:
- from F-terminal to 1st field coil
- other side to 2nd field coil
- from other side to brush
- through armature
- other side to A-terminal

So basically field coils are in series with armature between A and F terminal, correct?

Here's a two brush:

Whoa,... 65A generators are very different.

And testing requires measurement of amperage.

If you are not using a fully charged battery to test with, you will not get a proper output. Three or four volts sounds like no battery.

Time to buy a manual ('58 to '69), its all in there!

...Cotten

Like Cotten said: "sounds like NO battery"

Remember, its a generator, not a dynamo or magneto, so it will take voltage to make voltage. You must put 12 volts on the field windings or they will not create the required magnetic field which induces the current in the armature. Without external power all you have is the residual magnatism in the pole shoes (the iron plates that the field windings are wrapped around), so all you'll get is the 3 or 4 volts that you are reading.

If you are bench testing it by spinning it with a drill motor or whatever, you have to have all the components which are normally in the circuit: A good battery and a regulator. Connect it just like the diagram.

If it will "motor" when you connect a 12 volt power supply then it is probably OK.

good luck!

mike

If you look at the manual , you will need to have some special equipment to do a good test on the generating circuit , good amp meter or clamp type amp probe , rheostat , a load ( could use the head light )and as said above the other components in good working spec's.. There are still shops ( automotive ) that test generators , (you will have to call around),just to see if the Gen. is up to spec's and you can go from there with the other components and do not forget about the wiring, it is sometimes over looked in charging problems .The manual has things you can check ,like continuity of field coils, armature,commutator bars and brushes that can be done with a simple multimeter. Worn bearings can cause problems if worn badly.

I got the '65 Pan HD manual but can't figure out the INTERNAL wiring

The link found on this great forum showing the 12V chevy generator internal wiring makes more sence to me but is this as a 65A type HD generator??

I agree with all of you saying you need to test it as a whole system since it obviously needs power to generate electricity.
I arranged to have another generator and same result... so afterall the problem will be somewhere else. Battery (level) is OK and bike will electrical start. Will check wiring and regulator tonight.
However, regulator is electronic so I don't know what can be tested to rule out it's (mal) function.
any suggestions here?

if the genny will run as a motor and you have enough battery to start the bike that pretty much leaves the regulator and the wiring as the suspect components.

put it all back together and install a temporary ammeter in the positive (small) wire to the battery. then run the motor around 2000 rpm, ground the field terminal and see if it charges. if it does, replace your regulator.

john

Hey, how 'bout this one?
Have been having problems, pretty much knew it was the regulator-(solid state). Decided to try grounding the field just for the heck of it, I just flashed the field to ground and the generator light went off and after several days of riding it has stayed off when engine is running and seems to be charging just fine! Not sure what to think, is it "fixed"? and if so why?
Anyone out there have any ideas?
Doug.

Doug,

The solid state units, nothing mechanical and no moving parts, depend on "triggers" to toggle the circuits and a small amount of residual voltage to maintain the memory so it knows where it is, on or off.

Once in a while they forget where they are and everything gets reversed. when you "flash" it sometimes you get lucky and restore the original baseline. Exactly like rebooting a computer.

You probably fixed it, ride on!

mike

Hi Mike,
Thanks for the reply. This one really had me scratching my head. It just seemed too good to be true that it might be OK. I'm going to continue to ride it as-is and watch it closely. If it craps-out again, I think I'll go to a small Bosch Sporty-type set-up.
Doug.