Alternator wiring question
 

I bought a 74 2.7L 911 engine in parts and I've been assembling/rebuilding it for use in my 914-6 conversion. I'm to the point where I need to hook the alternator up.

The alternator is a later style with an internal voltage regulator. The back has three posts, labeled B+, D+, and D- and two male spade lugs. The B+ has a 10mm nut, the other two have 8mm nuts.

I assume B+ is the battery positive supply. Can someone explain the other connections?

http://forums.pelicanparts.com/uploa...1140918301.jpg

The harness has four leads.

A big red lead - I assume this is the battery positive terminal and goes to B+

A green lead with a lug for a post.

A brown lead with a lug for a post.

A black lead with a female spade lug.

Can someone explain where the green, brown, and black leads go?

http://forums.pelicanparts.com/uploa...1140918473.jpg

Also, the regulator has only one pigtail coming out of it that was pushed on the male spade lug by the B+ terminal. I assume its supposed to have two. Does the other go to the space lug by the D- terminal? What part do I need to order to replace this? Are all the internal regulators the same?

http://forums.pelicanparts.com/uploa...1140918570.jpg

Thanks much,

----Bill

Billd,

There was a very similar topic awhile back:

http://forums.pelicanparts.com/porsche-911-technical-forum/239180-alternator-instillation-problem.html

Hope this helps,
Rex

Bill,

The two-page alternator update bulletin in the following thread should answer your questions:

http://forums.pelicanparts.com/porsche-911-technical-forum/215907-need-help-installing-alternator.html

Thanks much for the replies. This clears up a lot.

What I know now is
B+ is indeed the red wire from the battery
D+ is the blue (not green) wire - to the charge light
D- is the brown wire
I should cut off (or tape off) the black wire. Its a vestigal DF wire from an older alternator with an external regulator.

I probed the two male spade lugs on the back of the alternator. They are internally connected to the D+ and D- terminals on the alternator. The internal regulator connects D- to one brush and regulates D+ down to DF and connects that to the other brush.

What I don't yet know is what part number replaces the internal regulator I have that is missing a pigtail. The one I have looks quite different than the one in the photos on the attached thread or on the Pelican site.

Does anyone know if the replacement internal regulator from the Pelican site will fit this alternator?

bump - any advice on the regulator?