Mike, I think you have nailed it exactly - I can't add anything. I have not actually had the pleasure of fixing one of the later design alternators yet, but I have filed your excellent description for my own use, when the need arises. Dick Benjamin -----Original Message----- From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of mike and linda sutton Sent: Monday, August 14, 2006 9:25 PM To: mailing-list@xxxxxxxxxxxxxxxx Subject: Re: IML: more on alternators Someone asked about mixing one style of alternator with a voltage regulator for the other....without being TOO overly technical, heres why that doesnt work. The early alternators were designed with one field brush receiving voltage and the other brush lead went to ground. The regulator - points style or transistorized - sends voltage to the field brush which goes thru the field coil and creates a magnetic field and then goes to ground, to be more specific. Now, the points style regulator simply opens and closes a set of contact points much like a set of distributor points according to what system voltage it senses and it pulses the contact points very rapidly, effectively controlling the voltage to the field coil which controls the output. The transistorized regulator does the same thing but uses a transistor instead of a set of points, but it is still pulsing the input to the field coil to control the output. Regardless, one brush is " hot " and the other goes to ground , usually right on the back of the alternator. In the later alternators, both brushes are " hot " ...current goes in one brush, thru the field coil and then out the other brush and doesnt go to ground at the alternator, it goes to ground when it reaches the regulator. It does the same thing, controls the effective amount of voltage and current thru the field coil by pulsing it, but it accomplishes this in a different manner. It still goes to ground but it does it at a different physical location. The short version of this, you should keep apples with apples, if your car has the older style alternator use the points style regulator or one of the solid state regulators designed to work with it. If you have the newer style isolated/insulated field brush units, use a regulator designed for it. Ill defer to Dick B on this for the electrical analysis, since he has counted more electrons in his working life than Ive been able to set loose by letting all the smoke out of the wires. Is this not the correct scenario Dick? Mikey 62 Crown Coupe ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm