Alternator regulators??

Going through my junk, I have a few regulators to choose from.
Two are Bosch RE55 (out of Bay kombi), one is RE57 I think from a Beetle.
Are they interchangable?
Any way to test them?

Also I have different one, see pic, also out of a Kombi. This one has 3 pins rather than two in Bosch, what happens with the third pin?

My '76 kombi has a 3 pin regulator with the same pin designations as the one in your second picture (except mine's a Bosch). The D+ goes to the +ve output on the alternator, the DF goes to the field coil on the alternator (which controls the alternator output), and the D- goes to earth.

HTH

I may be wrong but I believe the extra lead goes to earth, where i expect the two pins have an internal earth...
then again My Bosch alternator has an internal regulator...
I can't remember whether My Son's Beetle has 2 or 3 pins...

Lee

Cool, thanks.

So does any one know the difference between Bosch RE57 and RE55??

Andy wrote:Cool, thanks.

So does any one know the difference between Bosch RE57 and RE55??

They are both really the same.
One earths through the body,
the other through the 'extra' pin.

These are what I and a lot of others use on our Guzzi:thumb

Ivan

The external regulators don't seem to last that long.
My Son has used a few on His Beetle with an Alternator that uses an external regulator. Its the same with other vehicles I have owned over the years. Internal regulators seem to be better built or maybe larger or stronger, I don't know..
But I know which one I would rather have...

Lee