Technical Generator Light Illuminated

If you have another generator, you could try this and see if it works.

 

Yeah, I pulled the cover and manually closed the cutout relay. Voltage did spool up along with RPM, but I was a little hesitant to do that, because I don't want to fry the regulator or something. The cutout wouldn't stay closed though.

 

Yep, I may do that. Thing is this one is theoretically OK, ha ha.
The spare "good" generator had some of the magic smoke let out of it one day some years ago, that's one reason I replaced it, thought I wouldn't be able to depend on it long term. Between the three I should be able to get something rockin'.

 

Well I pulled the armature to take a look see inside, polish the commutator, s****e out the segments, carb cleaner &c, and finally seat the brushes for good contact patch by pulling a strip of sandpaper through several times.

Then I tried to motor it by a jumper between ground and field post and positive battery to ARM, negative to case. Just like in a manual. That didn't work. Hm, that must be the wrong way. Try that with solid state!

Jumpered the ARM and FLD and then it spooled up quickly, smooth and at a pretty fast clip! Yesterday it was slow and lumpy, so I got that goin' for me, which is nice. It also shows about 20 volts when spooled up with an impact drill and socket on the pulley.

I installed an older pulley, a little bit bigger in diameter, that I think is correct for the truck Y block. Should keep the generator RPM down somewhat. Take the time to use anti-sieze on bolts and things you work on - the next guy to work on it will thank you, and - it might even be you!

 

Success! It WAS the brushes, worn or burnt, hung up in the holders, etc. Seems to work better than ever, 14 volts at low idle, it never seemed to charge at that RPM before. Light used to take a second to go out, goes off right away now.

What did we learn boys and girls (other than I'm an idiot)?

I "***umed" the brushes couldn't be the problem because they were almost new. I didn't pay attention to the warning signs. The manual confused me a little, because they were a little unclear when talking about "low output" (voltage) and checks to make, including "output test" (current). I figured too if it would p*** 35 amps, the voltage had to be good. Therefore it had to be the regulator, etc. The full field tests for voltage weren't done under any kind of load. Somebody suggested I connect a brakelight bulb to the armature when fielded, that would have told the tale probably. A headlight lamp for sure. One thing I should have tried was jamming on the brushes while idling, but I had that stupid rubber cover on, and plus there's no way it could have been the brushes. But that trick may get ya home if the need arises. I guess Buick in the 40s had a system that would disable the ignition if the brushes got too worn or somesuch, so the car wouldn't even start. Tow truck drivers carried a jumper wire to at least get the car started and drive it to the shop.

Also, digital voltmeters aren't always good for making checks. They get confused by mechanical voltage regulators, the points pening and closing rapidly I expect. For generator checks and charging system, ****og voltmeters are plenty accurate enough.

 

Yes, success! I suggested the brake bulb for a load. My guess is that when you full fielded the generator, the brushes were arcing across to the commutator and giving a false positive. Thanks for the feedback. Good luck in the future.

 

No, thank You! I took it on a test run last night, just to be sure. I would swear it runs noticeably better, and hotter (better ignition?) but maybe that's my imagination. One thing I remember on the last road trip was the heater output seemed weak. Just for grins I should check spark quality. Hm.

Changing pulley diameters (larger) the average charge voltage is somewhat reduced but still in the green. With headlights on and heater blower motor set HI it maintains just below 14 volts cruising down the highway. I put the battery on a charger at home and it showed 86% charge.