3 stage regulator question

[jdoe71]

I recently acquired a Hehr Aqualine 10-82 regulator. The manual for the unit says the following:

<<
This regulator is a "high side" device intended. for use with "P" type alternators only. It cannot be used with alternators which are regulated through the ground side of the field winding.
>>

I understand a "P" type alternator is one which is set up for external regulation. But I don't understand the meaning of "high side" device. I also don't understand the 2nd line, I thought alternators were regulated by varying the voltage on the field. Can anyone enlighten me as to what this actually means?

I was thinking of using this with a Prestolite/Leece-Neville 90 amp alternator that has been re-wired for external regulation by grounding one side of the field to the case and running the other field lead outside the case to be connected to the regulator. Prestolite makes a kit to do this. This regulator can control the amp output and I going to set it at 50 max figuring that would easily re-charge our tiny 230 amp house bank and not kill the alternator. Will this alternator will work with the regulator?

[Whimsical]

AFAIK
A P type has the regulation in the positive side of the field winding and the other end is grounded as you suggest you will do to the prestolite.
An N type has the regulation circuit in the negative side with the other side going to positive.
So P or N just means where the reg is connected. Either type can have the reg internal or external to the alternator.
As most systems these days have a negative ground the high side is positive, high or above ground.

Mike

[jdoe71]

Originally Posted by Whimsical

AFAIK
A P type has the regulation in the positive side of the field winding and the other end is grounded as you suggest you will do to the prestolite.
An N type has the regulation circuit in the negative side with the other side going to positive.
So P or N just means where the reg is connected. Either type can have the reg internal or external to the alternator.
As most systems these days have a negative ground the high side is positive, high or above ground.

Mike

That makes so much sense, I can't imagine why I didn't equate the N and P to negative and positive. Thanks for the info, much appreciated.