Re: Getting a jump/Gener-Nator or Powergen/Intermittent power drop follow-up

Posted by Tim Cole On 2012/2/17 19:30:12

Wow! That sounds like a lot of trouble.

Anyway, when I run into this kind of situation I usually start with the vital statistics. I check all the wires and make sure they are going where they should. I have had reproduction harnesses with mistakes in them.

One thing I don't see in your story is whether these new regulators were being polarized. Usually there is a piece of paper in the box that says "Warning this unit must be polarized prior to initial start up" Since I always do this I don't know what happens if it is not done except that the Delco manual has all kinds of wild declarations of disaster.

The only way a generator can "burn up" is if the field wire is shorted to ground, or if there is an internal short either in the generator or in the regulator. So these parts must have some kind of problem. If disconnecting the field wire doesn't stop charging then there is a short in the components.

Now theoretically speaking I believe if you hook the battery up backwards and repolarize the regulator, the only problems will be with gauges. Maybe these regulators are wound in a different direction for ground polarity, but I really don't know. I only know there are people out there who hook batteries up backwards (they don't know any better) and the cars don't explode.

There are ways to isolate your kind of problem using power resistors to lock out the regulator, and an oscilloscope would really zero in on what exactly is going on. The whole system itself can be locked out and tested using an out of car battery. However, in many situations if the wiring is good, and the battery is good, and if the generator doesn't have visual damage a set of brushes and a new regulator gets the thing working again. However, this swinging ammeter indicates a voltage spike probably caused by a short or open in the armature or in the regulator. I think if the field coil in the regulator wears out it can make and break causing a voltage spike.

I handled a case of repetitive battery failure once and the problem turned out to be a defective harness causing overcharging. So I lean toward voltage spikes burning up your batteries.

Armatures do wear out, and fields wear out, and regulators are electro-mechanical devices so they also wear out.