sj410 alternator issues

[kiwizook]

I hooked up my alternator again the other day, but it didn't seem to work. I am assuming the bolt on the left hand side of the pic is the out put on it. someone told me you can revive it by putting 12v on the brushes for a verry short amount of time. something to do with restoring the residual magnetic field or something. any one that can shed some light on this issue?

Pic_0809_293.jpg (315.84 KiB) Viewed 9248 times

[Darrell]

Is that the early type with an external regulator ?
I've never heard of firing 12v down the brushes

I can photograph the relevant section from the workshop manual if it's any help.

[twiss]

I know on the newer alternators there is an exciter circuit. This sends 12v through the windings, which allows the alternator to charge at low revs.
If your battery light stays on until about 3000rpm, then that's your problem

[Darrell]

Twiss is correct that the windings (field coil) still need 12v to energise.
On the early 410 the alternator/generator is fed 12v from the voltage regulator via the ignition switch.

[kiwizook]

that does sort of make sense, I popped it open, and there was no regulators in there at all. where is the external regulator housed, and what does it look like? my wagon is still in a thousand pieces, so I'll have to find it among the parts to test it

[Darrell]

What year is yours as I think they are only fitted to 82-83 models.
If is has one it looks like this.

[kiwizook]

gotcha. mine is a '84, and it has a box that looks like that one, with the mark "new era" on it. that should sort it I would say

[kiwizook]

okay, trouble with alternators again, I hate these things! The "new" pickup needed a new battery, which I accidentally hooked up back to front, saw some smoke from the alternator, swapped it around, and all seems to work okay. then had an inkling it wasn't working, tested the output, about 12.4 volts, which seems a little low to me. sorted another one from a friend, was physically bigger, but the plugs matched, and it was a Japanese unit, hooked it up, and same story. then tried the alternator in the above picture, which was working fine, and same story again. swapped the charge controller over too, still same story. charging light does switch of, and all the alternators I have tried have been sitting a while. battery had about 11.9 volts in it, so alternator is raising the voltage a little, but the voltage seems to be too low. any thoughts on the situation?