Overheating generator

[ScottyHOMeY]

Tryting to get the SuperC squared away before winter, in case I need her to move that nasty white stuff around.

She hasn't been run a lot in the last year-and-a-half, and was giving me a little sass earlier this year about charging. I suspected a bad ground (thread for the bolt to ground the + cable was goobered up) and fixed that. improved a little and got a better charge, but nothing great.

Been following threads around here lately and went out this afternoon and touched up the points in the regulator. Voila! I thought 8^(

When I fired her up she showed about seven amps aharge at about 3/4 throttle. Went ahead and left her running, just to get her up to temp while I worked on some other things.

When I went to shut her down she was running right along, but showing an 8-10 amp discharge (no lights on), and the generator was VERY hot.

Understanding that a generator's output drops as its components heat up, my thought is there's something amiss in the genny to make it get that hot. A bearing maybe.

Your thoughts?

 

[Janicholson]

There could be issues with the generator. internally, there are possible shorts to ground, shunts to ground on armature windings, and a host of commutator issues. If it was way hot, and not charging, the tests in John Ts procedure posted below in several recent entries, is a great place to start. If there is burnt smell in the gen, and silver splashes inside the commutator, it is likely toast. JimN

 

[Will Sick]

There used to be a warning sticker on the battery box that said" generator will burn out if the ground cable is broken or disconnected". I remember that on a new B Farmall that my Dad bought in 1940.

 

[ScottyHOMeY]

I've found a really god motor/generator shop with an old-timer at the helm, one of those character types, and folks make a mistake when they take him for simple. Got an idea I'll be going up to see him.

Haven't noticed any smell, but I'll pull the band off tomorrow and have a looksee before I take it up to him. This has been a persistent problem this summer, so I'm hoping the fact that it charged so well initially today before giving out means that I didn't toast it. (Crossing fingers, here.)

Question. When I took the the generator from my BN up to him, I left the saddle-mount three-stud relay on top of it. Would there be any point in taking the four-point VR along on this trip to the shop?

 

[Janicholson]

Yes, It would be like taking your computer in to be repaired, and leaving the HDD home. JimN

 

[ScottyHOMeY]

Never saw that sticker, but know the concept.

The bad ground was there but just not good. I think somebody once tried to wind a coarse-threaded bolt into a fine threaded hole. I wound up tapping her out for the next larger thread. Some vague memory of getting a W-sized drill bit, because it would make for a tighter thread bite in the end than the fractional-size bit.

Point in the end though is that I never lost ground bad enough that it wouldn't run, though the flimsy connection may have stressed the generator as you suggest.

Them electrons run faster than pistons, dontchya know?

Thanks!

;8^)

 

[ScottyHOMeY]

Y'know, I kicked myself just after I hit the send button about that last part!

Thanks, Jim!

 

[John T]

If you remove the belt you may be able to feel/hear if the genny bearings are real bad which can cause the armature to drag the field poles and that can get em hot!!!! Maybe the bearings are dry??? If she didnt get too hot or wasnt dragging, the expensive armature may be able to be saved and maybe she just needs a bushing and the commutator turned n brush work, but sounds like you need to get inside it n looksee cuz I dont forsee much minor troubleshooting until you insure the condition of the bushing and hope the armatures okay..

The more typical genny heating is when the tractors shut down and a stuck closed cutout relay draws heavy current thru the armature and since the belt stops it from free motoring, they get hot.

let us know what you find

John T

 

[ScottyHOMeY]

Thanks, John.

Wonderin', too, what you call expensive in terms of the armature.

The work this fella has done for me before has all been what I call more than reasonable, but it sounds like you're talking about rewinding, and I could see where that would cost and hurt.

I ran out of light this evening, but I'll have the belt off first thing in the morning and put an ear to the generator as it turns, before I take it off. And, as below, I'll pull the bamnd and look to see if she got hot enough to sling solder all araound inside.

I do know she got some old hot. It didn't throw heat off like the manifold but, jeezum, she felt just about as hot to the touch when I started investigatin'.

I'll let you know how I make out, and thanks again!

 

[John T]

One last thing, a slipping belt can cause weak charge PLUS heat things up??? it good n tight???

John T

 

[ScottyHOMeY]

Yep, one of the first things I looked at. Both belts are about right. Fan howls like it ought to, and the right play in a new belt off to the generator.

When I first started chasing this down (like fixing the ground connection) I made a point of double checking the connections to the back of the ammeter and ignition button, too, while I could get to them with the battery out.

I made small progress with each session. Thought I had it licked the last time, she charged high for a while, which would have made sense if I'd been running her down, and then settled into a 0-1 amp charge showing on the ammeter. A week later, she was all akimbo again.

Following up on that, today's work, the first time I'd dressed the points in the regulator, got the results I talked about below. 7-8-9 amps charge at 3/4 throtle with the lights off. Wouldn't drop back more than an amp or two during a brief test of turning on the lights, high or dim. Never did settle back down, though, to just a few amps with the lights off.

That's about the pint I saw her dropping off tot he discharge state, and found the genny so hot.

Like I said, I'll roll it over by hand and listen and feel for anything when I take it off, but she's gotta go to the shop. 8^( Will keep ya posted.