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View Full Version : '82 XLH generator issues, any advice?


Wintersdark
8th June 2006, 02:45
Well, after a spontaneously dead battery and a day of careful searching, I've found that I've got a short to ground in my generator. Both the Armature and Field posts are shorting to ground.

I've removed the generator, but haven't dug into it yet. I understand the theory of how they work, but I've never been inside one before and my (lackluster, as usual) Clymer's manual just tells me to refer it to an expert. Unfortunately, experts want money, and I've got none, so I'm hoping for a little luck in finding the problem and *crosses fingers* fixing it.

Any helpful tidbits of advice in this? Generator tips and tricks? Things I should definately not do?

IronMick
9th June 2006, 04:40
Well, after a spontaneously dead battery and a day of careful searching, I've found that I've got a short to ground in my generator. Both the Armature and Field posts are shorting to ground.

I've removed the generator, but haven't dug into it yet. I understand the theory of how they work, but I've never been inside one before and my (lackluster, as usual) Clymer's manual just tells me to refer it to an expert. Unfortunately, experts want money, and I've got none, so I'm hoping for a little luck in finding the problem and *crosses fingers* fixing it.

Any helpful tidbits of advice in this? Generator tips and tricks? Things I should definately not do?

First time, two years ago, i wasted $40.00 having my gen rebuilt. Did it myself this past winter. It is a very simple device. Do it yourself.

Open it up. It will be filthy inside. Clean it up with a spray can of brake/parts cleaner and a toothbrush. Remove/measure/re-install the brushes. Use twist ties from the kitchen to hold them in place for the re-install. Check the small connecting wire for fray.

The gen need to be rebuilt every year. If you have the FM and a multimeter there is a whole series of tests you can do.

Note: the starter motor is virtually identical internally to the gen. It can use the same cleanup occasionally. It runs only a few seconds at a time rather than the rough treatment accorded the gen so it needs it not nearly so often.

Wintersdark
11th June 2006, 03:31
Righto, tearing into it now (after a really, really busy week). I don't have a FM, but I do have a decent multimeter. Anything in particular I should look for?

Wintersdark
11th June 2006, 04:27
Ok, got her opened up. Definately grimy, so I'm cleaning her up.

The short to ground is kinda confusing me, though. Trying to figure out where it is, or if it's supposed to be there.

There's a direct, unswitched line from the battery, to the voltage regulator, then to the generator, then through the body of the generator to ground.

When assembled, there is continuity between both armature and field posts and the generator case.

There is continuity between the copper commutator bars (is that the right word for it?) but not between the bars and the sharft.

One brush is attached to the armature post, no conductivity to ground from that brush. The other brush is mounted directly to the brush holder plate, and thus there is conductivity from that brush through the plate to the generator frame and thus ground.

This, though, seems like it's designed that way.

What am I missing?

IronMick
12th June 2006, 04:33
I think at this point you must have a FM. It has all these tests detailed: residual magnetism, maximum output, fiels coil tests [2], armature tests [3 of these], plus removal, disasembly, cleaning/inspection/repair. I cannot type all of this in!

<<
When assembled, there is continuity between both armature and field posts and the generator case.
>>

there should be insulating washers protecting the posts from the case. These look like cardboard washers.

Wintersdark
12th June 2006, 06:13
I think at this point you must have a FM. It has all these tests detailed: residual magnetism, maximum output, fiels coil tests [2], armature tests [3 of these], plus removal, disasembly, cleaning/inspection/repair. I cannot type all of this in!*laughs* Fair enough :)

<<
When assembled, there is continuity between both armature and field posts and the generator case.
>>

there should be insulating washers protecting the posts from the case. These look like cardboard washers.[/quote]There are, and they are working. I've been carefully over the whole assembly a couple times, and current can only flow where it's supposed to, so (wether or not it's charging correctly aside) the generator isn't the source of the short.

As the wiring between the battery and regulator, and between the regulator and generator is all good, that leaves the regulator.

Is it possible to test the regulator? I assume it somehow prevents current flow when the engine isn't running, as there's no switch between the main breaker and the regulator or between the regulator and generator.

I know the short's not happening from the regulator directly to ground, as it only exists when the whole charging system is connected. When I disconnect the regulator or generator from the system, the short is broken.



By the way, I *really* appreciate all your help in this, and my plethora of other problems :) If you're ever going to be out this way, let me know - Beers are on me!

IronMick
13th June 2006, 04:50
<<
Is it possible to test the regulator?
>>

I have another recent [like maybe one or two days old] post on this forum somewhere about testing the reg. There is one test that you can do easily and some others that require special equipment or techniques that i do not have. To get a thorough test you would have to take it to a auto electric shop; they may want both the gen and the reg so they can test them together.

The one test that i know of tests the part of the reg that prevents all power from draining from the battery overnight. You put your ohmeter on the two wires and read; then switch the leads and read again. One should give no resistance the other infinite.

I do not understand the electrical stuff very well. See if you can find my other post for a better explanation.