Change font size
It is currently Thu Mar 28, 2024 7:19 am


Post a new topicPost a reply Page 1 of 1   [ 9 posts ]
Author Message
 Post subject: Alternator wires
PostPosted: Sat Dec 04, 2010 12:23 pm 
Cams + Headers

Joined: Sat Feb 28, 2009 6:55 pm
Posts: 55
I'm swapping alternators on the rebuild and need help sorting the wiring. The new alternator is a Bosch and has 4 terminals (B+, 61/D+,D-, and DF) .The old one was ??? and had only 3 terminals (A, N, and EXC). "A" was hooked to "I" on the regulator. "N" was hooked to "S" on the regulator and "EXC" was hooked to "F" on the regulator. I'm not sure where "A" on the regulator went, but suspect it went to the ignition. So, obviously, one terminal on the Bosch won't get used, but which one, and what posts on the Bosch are "equivalent" to the "A,N and EXC" on the old one. I tried to sort it out in the Green book, but I'm "thick" electrically and got lost in the talk of stator, trio etc. Can anyone sort this rat's nest for me.
Image
Image


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Sat Dec 04, 2010 1:11 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3492
Location: Calgary, Ab
Put in a more modern single wire one, and get rid of the rats nest altogether?


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Sat Dec 04, 2010 1:36 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Dec 21, 2005 4:32 pm
Posts: 1927
Location: Didn't learn, now renovating bathroom #2, and you think cars are expensive!!!
Ugly Duck wrote:
Put in a more modern single wire one, and get rid of the rats nest altogether?

I agree totally, convert to a modern single wire, you will not be dissapointed

_________________
Volvord Image
1989 744TI Ford 302, Wilwood Brakes, 5 speed


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Sat Dec 04, 2010 3:05 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
It goes like this (follow along using your wiring diagram).

B+ connects to the battery + terminal via it's connection to the large battery + connection on the starter. They are connected together on the large starter stud. This should be the largest wire in your harness. Black wire.

D+ is the push on terminal for the exciter or charging light. A small red wire that goes to the dash cluster.

D- is the case ground and provides a ground for the alternator. It connects from the case stud to a mounting bracket bolt on the block. Often blue in colour.

DF is the field wire (green on my cars) and connects to the regulator.

_________________
Coburn Performance - OCD comes naturally.


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Sat Dec 04, 2010 11:58 pm 
Cams + Headers

Joined: Sat Feb 28, 2009 6:55 pm
Posts: 55
I traced the wires from the previously connected Alternator (bottom picture) and it was hooked up as follows: The "A" on the Alt. went to "I" on the reg. The "N" on the Alt. went to "S" on the Reg. The "EXC" on the Alt. went to "F" on the Reg. The "A" on the Reg. went to the big stud on the starter which also had the Battery + connected to it. I know diddly about it, but can only figure that the "I" on the Reg. is connected to the "A" on the Reg. other wise I don't see how the Alt. could charge the battery. If I hook the B+ on the Alt. directly to the big stud on the starter and hence to the battery, how is this "regulated", not going through the regulator. The Regulator is a Ford Motorcraft. As you can see I'm quite "thick" understanding this.
Bill


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Mon Dec 06, 2010 6:23 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
That's how externally regulated alternators work...here's a diagram of what happens.
Image

To control the output voltage, and maintain the correct battery charge, the field winding current is varied. The regulator basically monitors battery voltage and when the battery voltage is low allows more current to the field. In this way the regulator acts like a rheostat and turns up the current as required.

The voltage at D+ is about the same as B+ because the voltage drop in the trio diodes (0.6v per diode IIRC) is almost the same as that in the larger rectifier diodes (they convert the alternating current into direct current).

If battery voltage drops, the regulator circuitry senses that fact (at D+) and increases the current flowing into DF until battery voltage is restored. Most regulators also include some form of temperature compensation. A cold battery requires slightly higher voltage to fully charge. A temperature sensing element in the regulator increases output voltage at low temperatures.

I know - this is still Greek...but this is how it works.

_________________
Coburn Performance - OCD comes naturally.


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Tue Dec 07, 2010 11:57 am 
Cams + Headers

Joined: Sat Feb 28, 2009 6:55 pm
Posts: 55
Thanks for your patience on this Craig. Yes it is still Greek. What I don't get is - in the original (to me) set up there was no wire that went directly to the battery from the alternator. The only way the battery could get a charge in that set up was through the A post on the reg. which met the battery + post at the starter stud. Every schematic I've looked at since shows a direct connection from the B+ to the starter stud where it connects with the A from the Reg. and the + post on the battery. I can see how the battery gets charged in this set up because of the direct connection at the stud between B+ and Battery+ and I don't see that in the original set up. So my plan is to run an 8 gauge wire from the B+ on the alternator to the starter stud as per the schematics. This should work???
Bill


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Tue Dec 07, 2010 1:03 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
Are you using the correct regulator for that alternator...a regulator is not a generic part and the one used for the generator is a different animal all together. You can't interchange this part - the Bosch regulator runs the Bosch alternator (assuming 140/240 fitment) and the 122 generator runs though the Bosch regulator for this device. They are not the same. If you have the Marshal you need to run the correct regulator. As the diagram shows - they are part of a system and are specific to that system.

That gauge of wire (8) is sufficient - I'm one to run more wire gauge than needed in most applications. I'm running 4 or 2 ga in my car and I've got the 35 amp alternator. I'm able to upgrade when I want and won't have to re-wire. Currently (pun intended) I've got no plans as my system is not maxed and I don't run a big thumping amp like the kids do!

_________________
Coburn Performance - OCD comes naturally.


Top
 Profile  
 
 Post subject: Re: Alternator wires
PostPosted: Tue Dec 07, 2010 10:01 pm 
Cams + Headers

Joined: Sat Feb 28, 2009 6:55 pm
Posts: 55
O.K. There are cracks of light appearing through my dim, milk like, perception here. I have been trying to figure out how to wire a Bosch alternator into the Ford regulator with the wires leftover from what I assume is a Ford Alternator (or clone). I didn't know that regulators and alternators are "tied at the hip". I had the Bosch alternator (that came with the B20 I got from Dale) refurbished locally and plan to use it. I will get the matching regulator for it! The two compatible pieces and the schematic should clear things up to a large degree. Craig, thanks for hanging in while I stumble along here. It's much appreciated.
Bill


Top
 Profile  
 
Display posts from previous:  Sort by  
Post a new topicPost a reply Page 1 of 1   [ 9 posts ]


Who is online

Users browsing this forum: No registered users and 15 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron


Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
610nm Style by Daniel St. Jules of Gamexe.net