Electrical Dillema - Generator Discharges

[Bergy]

I recently took my A for it's inaugural run, 150 mi. after restoration. Everything ran well, except along the way a generator bearing froze up, threw the fan belt. Was able to drive home without a fan or generator since it was a cool day. I had the generator rebuilt and reinstalled.

After startup, the ammeter would register several amps Discharge at a fast idle. If I turn on the lights, then the ammeter would register several amps charging. After reading several posts on the forum, I suspected maybe my generator was improperly polarized, so I went through the steps of jumping a wire between the two posts on the cut out re-polarize the generator. No change.

I then called the shop that rebuilt the generator to ask their guidance. He questioned what the ammeter did when I turned on the lights with ignition off - the ammeter registered several amp Charging. His conclusion was that the wires were reversed on the ammeter.

I then swapped the wires around on the ammeter, and had no power to anything. I checked my wiring diagram and the ammeter was originally wired properly with the yellow/black on the charge side, and yellow on the discharge. Therefore, I put the wires back in their original positions.

When I went to start the engine to see where I was at, I had no power anywhere. I checked the voltages and discovered battery was totally dead at this point. Recharged the battery.

When I turned my power cut-out safety switch on to begin trouble shooting again, I noticed ammeter was totally pegged out (one way or the other) and smelled something hot, so I shut off cutout switch to investigate. Found that the horn wire in the harness was now totally fried.

One last check, before I came to you for help. I took the horn/light wire off the generator cut-out and only connected the wire from the starter. Started engine to see what I had - the ammeter was again showing discharge at a fast idle, same as before.

I couldn't find any info in the troubleshooting manual about a generator discharging on fast idle. Nor could I find any discussion on the forum.

Would appreciate any help or guidance anyone can provide on what my likely problem is and many thanks in advance.. The only thing that has changed since my 150mi trip was a rebuilt generator. But everything seems to be amok now. I have a new harness, cutout and ammeter on order, but would sure like to know what the root cause may be.

Is it possible all this trouble was caused by a bad generator cutout, or is it possible something is amok in my generator rebuild, or something else such as a shorted horn wire, or something else not yet identified?

Thanks again,
Gary Bergman

 

[Art Newland]

if you have a multi-meter, I'd check the battery voltage while the car is running, and then again while it's off. If the voltage is higher while running, then it is charging no matter what the amp meter is saying.

 

[Gary WA]

6 volt or 12 volt system? Positive or neg ground?

 

[Tom Wesenberg]

First make sure your battery is + grounded, then remove the belt from the generator pulley and jump across the two cutout terminals to make sure the generator spins in it's normal direction of rotation.

Once these two things check out, then turn the lights on with the engine off and see what the ammeter shows. If it goes to the charge side, then swap the wires on the rear of the meter. Many repro meters aren't set up the same as original meters.

 

[Bergy]

I haven' checked battery with car running, will do this afternoon. It's positive ground, 6v. As noted in first 4 paragraphs I jumped across the cutout, checked lights with engine off (charging), swapped wires on rear of ammeter. And thats when my bigger problems began - I had nothing, as noted in the rest of my initial post.

 

[Tom Wesenberg]

Make sure ALL the nuts are tight on the ammeter. This means the 2 nuts on the studs, then the other 2 that hold the wires. Outside of a loose nut on the stud, I don't see how swapping the wires can make you loose all power, unless you installed a fuse and blew it.

 

[Bergy]

Thanks for the thoughts and input. Problem solved - bad ammeter

I replace the cutout, problem still persisted. Tested the generator on a friends car and everything charged correctly. Then replaced ammeter and problem was resolved. I guess I should have checked the ammeter first after confirming and reconfirming that the wiring hookup was correct. At least now I have a spare cutout and learned something new. Apparently when the generator failed (bearings & armature) it caused the ammeter to fail also (was working before all this began).