Alternator question- Delco 10

Bret4207 · Jul 11, 2019

Which part usually blows where the battery gets unhooked in a Delco system? The diode, regulator or what?

JMOR · Jul 11, 2019

Somewhat dependent on what VR was used in the 10SI. Some have a regulator that go to full output under the 'no connection' situation, while others go into full shut down mode.

JDEM · Jul 11, 2019

The diode-trio seems to be the weakest part of the 10SI, 12SI, and 17SI alternators. It is a small set of three diodes bonded together and
not meant to carry much power. The main power rectifiers are pretty durable. If the SI is has the battery-voltage-sensing lead hooked up
properly, I will survive if the battery connection gets unhooked. I have done it many times with no harm.

Now if you have an SI with a so-called "one-wire" hookup? Then the battery-sensing connection has been eliminated and when the battery
connection is severed - it goes to full charge. That will not hurt it instantly but will if left that way for too long. Usually a power
rectifier overheats and blows.

JDEM · Jul 11, 2019

I guess I should of asked . . . 10 what? 10DN or a 10SI Delco?

Bret4207 · Jul 12, 2019

Delco 10si. I rebuild them these days for a lot less than buying a rebuilt one. It's $12-15 vs $60-85 up here. I thought I'd read here that one part usually was the culprit and the diode trio sounds right. I can get diode trios for under $3 a shot, so I thought I'd pick a few up.

Tom in Mo. · Jul 12, 2019

I unhook the battery nearly every time I'm finished using my old machines with the Delco. I think the lesson here is, don't unhook your battery while the engine is running.

Bret4207 · Jul 12, 2019

It's a case of broken fittings and the occasional limb ripping a wire loose. It's nothing done on purpose!

Alternator question- Delco 10

Bret4207

Well-known Member

JMOR

Well-known Member

JDEM

Well-known Member

JDEM

Well-known Member

Bret4207

Well-known Member

Tom in Mo.

Well-known Member

Bret4207

Well-known Member

Similar threads