OldIHC

I'm putting My 37 D2 back together after a complete restoration but can't seem to get the generator to charge, when I rev the engine the amp meter never moves. All the wiring is new but I labeled everything prior to dissemble so I'm sure its wired correctly. Here's what I have done.

1. checked the voltage at the battery.. 6.3 volts and when I rev. the engine the voltage never changes.
2. I've polarized the generator.
3. removed the fan belt and connected jumpers to the generator and it does turn like an electric motor.
4. visually inspected brushes and armature and they look good.

Is there anything else I can do to check the generator or voltage regulator. This generator only has 1 wire going to the battery terminal and the voltage regulator
is mounted on the generator.

--George

Can you get a picture of the generator? Chevy used a thrid brush generator with just a simple cut-out on the generator. All IHC's I have seen use a remote mount three unit regualtor. These have both a field terminal and a armature terminal on the generator. If yours just has a cut-out you can try jumping the cut out with the engine running. Don't do it for long, but just as a test to see if it will charge. Also generator system don't put out much at idle so run the engine at 1000 rpm or above when testing.

Thanks Cornbinder,

Here's a picture of My generator. I drew the short straw and had to work today so I didn't have a chance to put the generator back into
My truck but I'll get that done tomorrow. Let Me know how to proceed.

thanks again

--George

Yes that is a third brush type and that isn't a regulator, but a cut out. I wasn't aware that IHC ever used this type of generator, it was common on Chevys of the early 30's. Try jumping the wires across the cut-out with the engine running to see if it charges.
Voltage and current are controlled by the placement of the the 3rd brush, to the main brushes. I will have to dig back into my memory to remember which way you move the brush to increase output.
With this type of generator, the output is low but there realy isn't a regulator that sets the voltage, more that the generator charges whenever the engine is running. Check the water in the battery more often.
It was a cheap way to make a chargeing system, not nearly as complex as the three unit regulator system used by later trucks. With the seperate regulator, both voltage and current are regulated. With 3rd brush type, output current is useally limited around 20-25 amps, while the three unit reg type starts are 30 amps with 42-45 or even 50 amp units optional.
EDIT: I did a little digging and that is the correct genny for 1937 D2, so I guess they did use a 3rd brush on some models.

Thanks Cornbinder,

I'll try what You suggest and let You know.

Good stuff

Well I jumped the cutout as suggested but instead of charging, the amp meter was showing discharge, also the battery voltage dropped from 6.32 volts to 6.19.

I guess I can take the generator apart and check the brushes & wiring as the insulation on the wires looked suspect, although I used an ohm meter and did not find any shorts, unless You have other suggestions.

--George

Are you sure it is polarlize correctly? If you motored the gen with jumper cables the oppsite polarity of the truck, then you re-polarized backwards and that would cause the problem you show.
try polarizeing in place by jumping the cut-out with the engine off, then start and see if it the cut-out will pull in on its own, if not jump it again and take readings.
Remember, these truck were + ground orignally, but someone may have changed it along the way, and may or may not have swapped the cables on the ammeter.
Also don't forget that gennys don't charge at idle speed, esp 3rd brush types. you need engine speed over 1000 (over 1500 even better) to get a sense if it will charge.

It's definitely positive ground and I did polarized it with the jumper cable to the negative battery terminal and also rev'ed the engine
when checking to to see if it would charge. I'll double check My steps again and also trace the wire to the amp meter to make sure its on the correct terminal.

When I motored the generator I did verify it was rotating in the correct direction, is this an indication its polarized correctly?

--George

No it will motor the same direction regardless of polarity, you must reverese the field winding realitive to the armature to reverse direction and this often requires changeing the brush mounting also unless they are 90 deg to the armature. In otherwords it takes internal modifaction to reverse direction. This is also why starter motors (or the wound field type) will always turn the correct direction regadless of battery polarity.
A generator that is not turning fast enough to produce current will show a draw if the cut-out is bypassed, it( the cut-out) is there to dis-connect the generator when it is not produceing enough to charge so would be drawing the battery down instead of chargeing it.

Problem solved.

The armature was bad, I dropped the generator off at a local shop here and had it repaired, its charging now.
thanks for all the help cornbinder, I learned a lot. On to the fuel gauge and water temp gague.

--George