Alternator output stud

[kenbo]

the 1/4" B+ stud that you are referring to is actually a smaller dimension in the inside where it attaches to the positive side of the bridge rectifier. Not knowing which alternator Powerline is using as a base That interior dimension could be as small as 8 but most likely a 10 or12. That is your limiting dimension, not the external stud size that you see.

The heat damage that was in your first picture indicates to me that you had a very high resistance connection and the 1/4" stud wouldn't be the first place I looked for issues.

Contrary to what your rebuilder said about dielectric grease melting, I have always used 3M silicone brake grease which is an excellent dielectric and is designed to work at temperatures that exceed what alternators produce. Of course, a well-fitting terminal boot keeps things clean and tidy.

What kind of belt(s) are you driving that alternator with? And have you ever considered removing the internal rectifier and mounting an external one? Usually removes about half the heat load from the alternator. It's a good workaround for small case alternators that are tasked like yours.

[sailingharry]

Originally Posted by Bill O

What no pic of a bright shiny new alternator??!!

Just for you! The powrder coated fan has GOT to make it run cooler! Or at least LOOK cooler! Especially since it is a nice cold blue.

[sailingharry]

Originally Posted by kenbo

The heat damage that was in your first picture indicates to me that you had a very high resistance connection and the 1/4" stud wouldn't be the first place I looked for issues.

Contrary to what your rebuilder said about dielectric grease melting, I have always used 3M silicone brake grease which is an excellent dielectric and is designed to work at temperatures that exceed what alternators produce. Of course, a well-fitting terminal boot keeps things clean and tidy.

What kind of belt(s) are you driving that alternator with? And have you ever considered removing the internal rectifier and mounting an external one? Usually removes about half the heat load from the alternator. It's a good workaround for small case alternators that are tasked like yours.

Yes, it's resistance heat for sure. I'm assuming it's the stud. It could be the stud-to-lug connection -- I've asked the mfg to recommend a torque for the nut, that might help. It could be the crimp, but that area doesn't look as hot as the stud area.


Dielectric grease. I've always found that weird. It came into play decades ago to lubricate a breaker ignition, and its big selling point was that "dielectric" means "insulating" and it wouldn't bleed off the high voltage. But these days, it means "good for electrical connections" -- which is the opposite of "insulating."


This alternator is driven on a dedicated multi-v (it's not a "serpentine" because it doesn't "serpent." Off loading diodes is often talked of, and sure makes sense. I've not seen a lot of pictures/details of those that have done it, including how to retrofit existing alternators. One big hurdle is the wires -- how big are they? Say 1/3 the cross section of my existing 2/0 output wire? Somehow I would have to bring out 3 terminals each handling about 50A, and a way to connect them. Sounds do-able, but it's major surgery. I guess drill holes in the case, add insulating bushings, etc. Granted, my 2/0 could technically be #2, and the new triple could be as small as #8 each, maybe even #10 -- but I'd want #6 I think. (#10 in the engine room is rated for 51A, and they would be carrying 50A each).