Generator And Rectifier Operation Questions

[marcair]

I have installed a Gen 1 in a daily driver car about 5 years ago. The electrical system is powered by an external alternator belted from a pulley threaded into the rh end of the crank, similar to the blower setup. The method supplies all the necessary power for the AC unit, power window/seats, stereo amp, lights, etc. The original generator and rectifier are wired into the system EXCEPT a 30amp inline fuse is removed from the 12v output lead of the rectifier. Thus, the sys is isolated. My thoughts are that if I ever break the alternator belt, I could always install the fuse and limp home on the generator. All is well until last Sunday in the rain on the highway. The car filled with black smoke. I immediately noticed the rectifier was HOT, very hot. So I separated the generator from the rectifier at the connector approx. 4 inch from the rectifier. One of the mating 3 yellow leads from the generator and from the rectifier at this connector was fried and the black insulation material in the rectifier melted and ran down a bulkhead. The rectifier cooled down. No fuses in the primary elect sys blew. After 200 miles since this happened, I do not notice any further issues.

1.Could the cause be water got into the empty inline fuse socket closing the circuit and 12v from the alternator is not compatible with 12v from the generator? Would installation of a diode be a good idea? Keep in mind, my intention is never to use both sys at the same time.
2.Since the generator is intact and operating but not linked to anything to consume power, is this a bad thing?
3.If after a thorough examination of the generating sys wiring I find no chafed wires or other problems and each of the 3 yellow leads from the generator produce ac power, would replacing the rectifier be ok?

From San Diego and on temporary assignment in Greensboro, North Carolina: anyone offer a local competent repair/racing shop with routine maintenance?

By the way, my engine mod and swap was performed by Downs Engineering home page

 

[IG.]

Man, it took me a while to read and comprehend, and I still didn't get it completely. But I think what I got was the your Gen 1 generator + voltage regulator were lifted from a 'Busa and installed in your fancy car, and perform the same job as if they were in a 'Busa body, right?

I think I have a good guess regarding what happened.

Because of size constraints, motorcycle generators work slightly differently than car alternators. Without going into details, the significant difference is that the excess power from the generator (when rpm is higher than idle) is being shorted by the voltage regulator. This means that the current going through the three yellow wires from the generator is pretty strong most of the time regardless of the load. And this in turn means that the slightest degradation of the quality of the connection will create excessive heat. Normally, it's pretty warm to the touch for this reason.

Something got into the connector which contributed to poor connection. As a result, strong current plus poor connection caused extreme heat, which in turn melted the connector.

If you didn't do anything to that connector, then my educated guess would be this. The oil around the generator coils is under pressure. A wire going from the generator, is surrounded by an insulation which acts as a small tube. If not completely sealed, over time, oil pressure moved small amount of oil through one of the yellow wires and right onto your connector, causing poor connection, and overheating. I would open the connector and inspect with a flashlight for any oily residue around. Or look for any other possible source of a substance which may've gotten inside.

Another more trivial explanation would be that the connection in that wire was poor to beging with. As time goes by, heat and humidity contribute to deterioration slowly degrading the quality of the connection, causing more heat, which only accelerates this process.

You can guess how I know all that, LOL.

 

[marcair]

Sounds good. Will examine the wiring. Thanks

 

[dadofthree]

There's a double E hanging around, I don't know how well water would conduct 14 VDC.