Another voltage regulator question.

[clausoe]

I’m wondering if the voltage regulator can fail in such a way that the rotor gets completely grounded and fully magnetized all the time. If this happens and the rpm is at driving levels the alternator will charge all it can and again the rotor gets more magnetized and so on, the evil circle is a fact. If this can happen will this overload the alternator itself? If so what parts get burned? I’m trying to find out why the regulator and alternator have a tendensy to fail at the same time, and why. I'm running the system after 69.

Claus

[Nacho-RT74]

electronic regulator isn't easy to fail, but I have had rotor damaged and never regulator damage at the same time.

weird.

I'm still trying to understand the way that rotor gets grounded. what it happens to get that fail.

[Plumcrazy]

I've seen that many times.  The regulator full fields the alternator and you end up with a runaway alternator.  17,18.19 volts is possible.

[clausoe]

Yep, that was the voltage between the battery poles just before everything stopped working, and fried the coil. I'm fed up with these regulators malfunctioning and frying the alternator, so I went to the local junk jard and found an alternator from a 93 mazda. It fit almost right in with the right kind of pulley and all, just had to put on a different "slide bracket", don't know what it's called. It's internally regulated and I can connect the sensing wire directly to the charge current wire if I want to, (so it's now a one wire alternator). I first used the existing field current from the ign for the regulator sensing but there was enough voltage drop through the bulkhead, ignition switch etc. that the charge voltage became a bit to high. It is now a steady 14,6 volts at the battery.