Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 03-23-2013, 09:41 PM   #1
James G.
Senior Member
 
Join Date: May 2010
Location: maryland
Posts: 183
Default 3 wire Alternator hookup, 6 Volt Pos Ground

I have a wiring diagram from the web which shows a lot of detail but not the purpose of the wire from "left spade post #1". It is shown going to an indiactor light or resister. What is the purpose of the lamp and/or resister. Also what would be the value of the resister?

The "right spade post" is jumper-ed to the alternator power output threaded post. All this make sense except for above questions!

email me details please
[email protected]
James G. is offline   Reply With Quote
Old 03-23-2013, 10:58 PM   #2
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,560
Default Re: 3 wire Alternator hookup, 6 Volt Pos Ground

James, try www.alternatorparts.com or www.MadElectric.com I found some good info there some time ago. Bill W.
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 03-23-2013, 11:12 PM   #3
Mike V. Florida
Senior Member
 
Mike V. Florida's Avatar
 
Join Date: May 2010
Location: South Florida
Posts: 14,054
Send a message via AIM to Mike V. Florida
Default Re: 3 wire Alternator hookup, 6 Volt Pos Ground

It is used to energize or excite the field windings inside the alternator. The alternator cannot start charging until there is voltage on the field windings and a magnetic force is created. This terminal will cause the ignition warning light (idiot light) if installed, to illuminate if the ignition is turned on and the alternator is not supplying enough voltage.

This site should give you all your answers, if not ask here again.

http://bob_skelly.home.comcast.net/~...ternator1.html
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

Last edited by Mike V. Florida; 03-23-2013 at 11:17 PM.
Mike V. Florida is offline   Reply With Quote
Old 03-24-2013, 01:56 AM   #4
Willie Krash
Senior Member
 
Willie Krash's Avatar
 
Join Date: Jan 2012
Location: Phoenix, Oregon
Posts: 661
Default Re: 3 wire Alternator hookup, 6 Volt Pos Ground

Sponsored Links (Register now to hide all advertisements)
#1 is as Mike says. #2 is the sense wire. You can sense from the alt's battery post or battery.

#1 is an output wire btw and is tied to the diode trio. Any load greater than an a couple of amps will quickly kill it, and the alternator will go off line.
On modern late model cars with conventional ignition systems (50/60's cars) #1 tied to the key without a diode, light or resistor in line will power the cars coil. It will not turn off with the key.

If you choose to use a wire at #1 you could use a small diode. You also could use the light as it is an indicator that the alternator is working. As it is an output post it turns the light out by suppling the same voltage on the filament as the supply side does. I'd just use a one wire alternator.
__________________
Mike Stitt
"A business that make nothing but money is a poor business."
-Henry Ford

Last edited by Willie Krash; 03-24-2013 at 02:03 AM.
Willie Krash is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 05:27 AM.