alternator burning

[Fspallino]

I have a 1993 m35a3 with a cat 3116, the other morn I started it to warm up and noticed the alternator smoking and smelt like burning wire. I shut it down quickly but started hrs later to move truck and no smoking and the batteries gauge is charging normally. I don't know what's wrong with it now. Seems to work fine, if I drive the truck will it go on fire?

 

[Vondy]

I had the same problem on my A2 a few weeks ago. I left it running long enough to see that my power cable was shorting out against the cover plate. Removed the cover plate and added some shrink tube to the wire just in case. Still have not replaced the cover, but I think I will add some spacers under it to see if that solves the issue.

 

[Fspallino]

thanks vondy

I had the same problem on my A2 a few weeks ago. I left it running long enough to see that my power cable was shorting out against the cover plate. Removed the cover plate and added some shrink tube to the wire just in case. Still have not replaced the cover, but I think I will add some spacers under it to see if that solves the issue.

I did see some white residue on the plate and looks like it def arced, ill take it off and rubber cover it. Was odd because all month driving it would give me a false reading at the battery gauge , would charge great then drop. Must of been grounding then

 

[goodguyzy]

I had the same problem on one of the A3's. This model is known for frying alternators due to the sit time and dead batteries. I would replace it as soon as possible. I ended up replacing mine with a new SAW from Eriks,

 

[doghead]

Be sure all your battery cable connections are clean and secure.

 

[EWhytsell]

While we're talking about alternators I have a problem with mine as well. It can't be charging or charging enough and I'd like to try to fix the alternator myself. System reads < 24v when everythings off, once I start the truck I get more than 24 volts, 25 max. Its the 60A style with the regulator on the back of the unit. I'm very capable at electronics repair since its my day job, but I need info to proceed. On the bench I was able to prove that the exciter works to energize the alternator and the pulley becomes very hard/impossible to turn. When I put it on the truck the wiring coming off the windings aren't giving much voltage. One is showing 12-14v depending on engine speed, another is showing 10v and the third has nothing. I turned the regulator voltage adjuster both ways and its turned all the way up now to get what I've got.

Any ideas, or direction to some nice schematics on it? I haven't had much luck finding anything.

 

[donnerwetter58]

This all sounds too familiar.
My A2 had similar problems this past Spring. It charged fine but there would be a light sweet burning smell at times. One day it quit charging. I looked around and found evidence of arcing between the alternator battery connection and the sheetmetal cover. I insulated it and all was well for a while. I would still get the smell but charging was fine. Then one morning I started it and there was no alternator output or smell. I found one of the stator windings had shorted and burnt. It was quite obvious as the lacquer was gone and the winding was black.
Searching the forum, I found many in the same boat with the Prestolite alternators. I decided to go with a Delco conversion. The conversion brackets came from tm america. Total cost for alternator and conversion brackets was $170. The Delco alternators and parts for them are everywhere. All I need now is an air freshener with a sweet burning scent.

 

[dangerfieldinc]

Do you have web site and part number for the conversion brackets and delco alternator

 

[donnerwetter58]

Do you have web site and part number for the conversion brackets and delco alternator

The alternator came from Pat's Small Engine Plus. Part # AHADR0009. It's a Delco 27SI style 24 volt 65 amp alternator.
The bracket set came from George, user name " tm america " on this forum. The brackets work very well. They use the original belts. You will need to bore the pulley from the Prestolite alternator to fit the Delco unit. You can do it with a drill but a lathe is a better option. The only other note is to move the fuel filter bracket from the top of the frame rail to the bottom of the frame rail for sufficient clearance to tension the belts. Do this while the alternator and old mount is removed.