1935 Generator test.

TerriblePainTerriblePain Posts: 28Member
in HUDSON
A wire was disconnected from the generator on my straight 8 Hudson by the previous owner who had passed away.  That made me assume it must have a problem.

With the car running, I cannot get any voltage when reading between the terminals or between the terminals and ground.

I see guys on YouTube will connect the two terminals with a jumper and touch that to the negative battery post (for a positive ground car) and see if it spins like a motor.

Is this method advised...or has anybody tried it?
What is a good source for these generators?  I assume they are fairly unique.
Thanks.

Comments

  • GeoffGeoff Posts: 4,714Senior Contributor
    Which wire was disconnected?  A or F?  If you ground the F wire and connect the A wire to the battery, with the fan belt off, the generator should spin with a current of 4 amps.  If it does not  the generator is faulty.  It is not a big job to fit any generator from a post war Hudson, Chrysler, Packard,  Studebaker etc. (all Auto-Lite)   and a matching voltage regulator. 
    If you're stuck in a hole, stop digging.
  • TerriblePainTerriblePain Posts: 28Member
    The A wire was removed.
    I will try that test.
    If it seems to work, can I hurt anything by reconnecting it if the voltage regulator is bad?  Can the regulator be tested?
    The former owner had 19 cars he tinkered with.  I assume he disconnected it for some reason.
  • TerriblePainTerriblePain Posts: 28Member
    I hope it wasn't a bad idea, but my friend hooked the battery charger positive lead to F and the black lead to A.  The generator  didn't spin.
  • 54coupe54coupe Posts: 1,122Member
    I would do it with an actual battery. I don't think a battery charger generates enough amps to do the trick.
  • TerriblePainTerriblePain Posts: 28Member
    You were correct.  The battery charger didn't spin it but the battery did.
    I hooked it up and started the engine.  I get no change in voltage (between engine running and not running) at the battery and the ammeter light still glows.
    My friend said to short between the A and F terminals to 'polarize' it while it is running.  I tried a few times.  I didn't get a spark between the two terminals and voltage at the battery stayed the same.
    I cleaned all of the connections on the voltage regulator....still no change.
    Any suggestions appreciated.
  • GeoffGeoff Posts: 4,714Senior Contributor
    You need to check the current when the generator is spinning with the battery negative connected to A and the  positive connected to F, and also the the generator casing.  It should be 4 amps.  If higher or lower than this your generator is faulty.  Have you checked the brushes?   Could be an open circuit field coil.  You really need to take it to a qualified auto electrician.  You can try manually closing the cut-out points with the engine running.  If they do not stay closed the generator is faulty. 
    If you're stuck in a hole, stop digging.
  • GeoffGeoff Posts: 4,714Senior Contributor
    Another thought, have you tried advancing the third brush?  Move in the direction of rotation to increase charge
    If you're stuck in a hole, stop digging.
  • TerriblePainTerriblePain Posts: 28Member
    Today I removed the little cover from the back of the generator.  I snapped all of the brushes a little to help them make good contact.  I carefully ran a pick along all of the grooves between the copper segments to remove the black debris.  I gently rubbed a blackened area on the copper segments clean with a brillo pad.
    I hooked it back up, started the car, and read the voltage at the battery.  It was still at 6.49.....my normal battery voltage.
    I set my screwdriver between the A and F lugs quickly, which generated a spark, and measured the voltage at the battery.  It was 6.6 and the Ammeter light on the dash went out.
    I am not an expert by any means, but this got mine working.
    Thanks again for the help to commenters above.
  • GeoffGeoff Posts: 4,714Senior Contributor
    The light may have gone out, but this by no means indicates  the generator is working correctly. You need to disconnect the A wire and   fit an ammeter in there to see what amperage the generator is producing. Is yours a simple cut-out, or a two stage regulator?
    If you're stuck in a hole, stop digging.
  • TerriblePainTerriblePain Posts: 28Member
    I don't know what kind of regulator I have.  It is about an inch wide and two inches long.  I will try to measure amperage.
    I was getting about 6.8 volts at the generator and 6.6 at the battery with it running.
  • GeoffGeoff Posts: 4,714Senior Contributor
    Sounds like you have a cut-out with no regulator.   The current is increased by moving the third brush in the direction of rotation.  There should be a cap on the  F terminal grounding it if that is so.  Is this a Terraplane  Special?
    If you're stuck in a hole, stop digging.
  • TerriblePainTerriblePain Posts: 28Member
    I think my car is a plain Hudson.  It did have two tail lights and vent windows back in its day.  Someone told me that it might be a Deluxe because of those items.
    Which brush is the third brush?
    The wire leaving the F terminal of my generator does get grounded by one of the bolts holding what I call the regulator to the firewall.  I don't have a cap on the F terminal that I know of.
    Thanks
  • GeoffGeoff Posts: 4,714Senior Contributor
    The third brush is the one you can see when the cover strap is removed. it is held in position by a flat spring, and can be moved.  
    If you're stuck in a hole, stop digging.
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