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MF 50a alternator replacment and wiring guidelines

mitch504

Senior Member
Joined
Feb 27, 2010
Messages
5,776
Location
Andrews SC
I could draw you a simple pic that would show the minimum wiring needed, but I don't know how to post it.:rolleyes:
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
AC Delco self exciting alternators can be wired in different configurations.
The one I use and prefer is one of them.
Confusion seems to surface when someone refers to a one wire set-up.
There is a true one wire configuration no doubt about it.
A Google image search will show the different ways the Delco alternator can be wired.
I used that search many years ago to figure out how to create the configuration I prefer. I guess mine could be called a three wire set-up.
 

Delmer

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Jan 3, 2013
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8,865
Location
WI
I guess the disagreement is that I would call only a one wire alternator "self excited", any other Delco alternator would be "internal regulated" and need at least one SWITCHED excite wire. Maybe Delco has been calling them "self excited" all along and Mitch and I are wrong. I will try to use only "one wire" or "internal regulator"
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
Delmer; You and Mitch are not wrong in any way in my opinion.
I copied the following info. from a website. I have been aware of the three configurations for a lot of years.
Those three configurations is what I causes so much confusion for me, because when I see someone wanting help it is hard to know which of the three they have.
That is why I always ask to see a picture of the alternator terminals with the wires on them.
I'm not trying to be know it all by any means. Just trying to help members understand how a delco alternator can be installed in different ways.
-----------------------------------------------------------------------------------------------------------------
One-wire Alternator:
Is another name for the Self-Exciting Alternator . You only need to connect the battery wire (one-wire).
The alternator turns on the voltage regulator when the engine starts turning the alternator.

Two-wire Alternator:
Most standard and all self-exciting regulator alternators will work using the two wire setup.
Two wire means that you use the main battery wire to the back of the alternator and also ignition wire to the
#1 terminal to activate the alternator. With this setup the alternator starts charging as soon as the engine is running

Three-wire Alternator:
This setup uses a battery wire, ignition/warning light wire and voltage sensing wire, Three wires. Voltage sensing is used when you want the alternator to read voltage at some point other than the battery. Or the battery wiring is such that the battery is a long distance from the alternator.
 

mitch504

Senior Member
Joined
Feb 27, 2010
Messages
5,776
Location
Andrews SC
Yep, the 1-wire is what I was calling self-excited, and the 2-wire is what I was calling standard, or internal regulator. I am glad you posted that because I understand the 3-wire better now.

On a side note, I seldom use the $35 1-wire from the parts stores if I can use the 2-wire setup with a manual switch or an oil pressure switch. I started having trouble with those regulators sticking and killing batteries. I don't see that with the heavy duty 1-wire alternators.

BTW, what website was that? I'd like to go see what else they have for me to learn.
 

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,865
Location
WI
And on tractors or heavy equipment with very little electrical draw, we usually tie the third wire to the battery wire, like in all the pictures and diagrams shown. This effectively makes it a two wire alternator, which we get away with as long as the main cable is in good shape.

The voltage regulator for one of these delco's is about $5-10 and can be swapped on the machine in very little time. That regulator is the only difference between one, two or three wire, and even some "ONE WIRE" regulators will have the two terminals, even though it will work without them hooked up. confusion never ends.
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
https://alternatorparts.com/what-is-a-self-exciting-alternator.html
I change out the standard regulator to a self exciting one so that it will begin to charge as soon as I start the motor. No need to speed it up to get it to charge with a three wire set-up.
They can be purchased at NAPA. here is one one ebay --->https://www.ebay.com/itm/Delco-10SI...405973&hash=item3d693084f5:g:gaIAAOSw~K9dyYfo
For sure Delmer, it makes it very hard to help members that have butchered wiring and are trying to installor fix a delco alternator.
 

steven mf50A

Member
Joined
Aug 28, 2020
Messages
11
Location
Saint-lin-laurentides
Hey Guys
So for the wiring its all good now. I connected it like the delco drawing and fused it as well as added the volt meter on it and its charging now. Some wires were not connected the way you told me so after reviewing the wires one by one now it work good. Thanks all for the help!!
 
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