Alternator Wiring Revisited

L.Fure

Well-known Member
After mudding up the post T L started I decided to start a new post on the subject of why some alternators only use one wire, and others use the two wires from the plug, like mine does?
 
(quoted from post at 18:05:10 03/06/18) After mudding up the post T L started I decided to start a new post on the subject of why some alternators only use one wire, and others use the two wires from the plug, like mine does?
wo in the plug plus BATT wire was the way GM did it. It provides a charge warning light and remote battery sense and an excite current that will allow the alternator to start charging at a slightly lower rpm. The one-wire came about later as a convenience for hot rodders and stationary engine applications where some of the other features were not important. The one wire uses a different VR that senses internal to alternator and 'self excites'. Makes life simple and you primarily give up charge warning light. The often repeated complaint of needing to rev engine to start charging is making a mountain out of a mole hill, unless you only idle your tractor & never really use it. There are dozens of different one-wire VR's and some require very little speed to start charging.
 
I think it was Dell, bless his heart, who
always said you had to "jazz yer cold engine to
get it to start charging".
I never understood that thinking since there is
plenty of battery to run your engine for a
while and warm it up a bit before jazzing it.
That said, I always go with a 3 wire setup.
The tractors I mess with had a warning light
from the factory and it's pretty easy to
reconfigure the old harness for an alt and
reuse the light.
 

JMOR,
Thanks for that explanation. The reason I changed the wiring on my tractor was that I decided to use a voltmeter instead of an amp. gauge. I ended up connecting a bunch of wires together with a machine screw, two washers, nut, and lots of electrical tape. Then I ran a jump wire from that mess to the ignition/start switch. I have a junction block coming in the mail so I can tidy up my mess. I'm also going to replace a lot of the old wire with new, because of the brittle coating on some of them. I don't want to have all the wires burn up and have to go through all the trama of redoing everything. I'm sure I'll be back here with a bunch of dumb questions after I start that project.
 
(quoted from post at 21:22:56 03/06/18)
I'm sure I'll be back here with a bunch of dumb questions after I start that project.

no worries. i won't speak for anyone else, but i've nearly always got a dumb answer ready :)
 
(quoted from post at 02:53:57 03/07/18)
(quoted from post at 21:22:56 03/06/18)
I'm sure I'll be back here with a bunch of dumb questions after I start that project.

no worries. i won't speak for anyone else, but i've nearly always got a dumb answer ready :)

Okay, how about this one. What color should the red tail light be on the back of a 8N?
 
(quoted from post at 21:58:50 03/06/18)
(quoted from post at 02:53:57 03/07/18)
(quoted from post at 21:22:56 03/06/18)
I'm sure I'll be back here with a bunch of dumb questions after I start that project.

no worries. i won't speak for anyone else, but i've nearly always got a dumb answer ready :)

Okay, how about this one. What color should the red tail light be on the back of a 8N?

:lol:

i'm colorblind - u might wanna ask someone else :D
 
(quoted from post at 22:14:53 03/06/18)
(quoted from post at 21:58:50 03/06/18)
(quoted from post at 02:53:57 03/07/18)
(quoted from post at 21:22:56 03/06/18)
I'm sure I'll be back here with a bunch of dumb questions after I start that project.

no worries. i won't speak for anyone else, but i've nearly always got a dumb answer ready :)

Okay, how about this one. What color should the red tail light be on the back of a 8N?

:lol:

i'm colorblind - u might wanna ask someone else :D
White/clear. The lens is red. Learned that from HFJ. ;)
 
AFAIK, GM never made a "one wire alternator" in the sizes/versions we are dealing with here.

But the aftermarket seized on the opportunity to make a "one wire" bastardization of those alternators to fill a niche market of those who are either too inept or too lazy to simply connect up an alternator conversion in the manner in which the original designers/manufacturer of the alternator intended.

YAMMV!
 
(quoted from post at 23:29:37 03/06/18) AFAIK, GM never made a "one wire alternator" in the sizes/versions we are dealing with here.

But the aftermarket seized on the opportunity to make a "one wire" bastardization of those alternators to fill a niche market of those who are either too inept or too lazy to simply connect up an alternator conversion in the manner in which the original designers/manufacturer of the alternator intended.

YAMMV!
ob, you are safe with the AFAIK, SINCE GM DID ACTUALLY MAKE A ONE-WIRE UNIT (1986). I am e-mailing you the pdf .
:)
 
THANKS, Jesse! There's always gotta be an exception! Have you ever seen one "in the wild"?
 
I put a one wire alt. on my 62 Scout when I needed more amps to run the plow set-up about 10 years ago,it works great,starts charging with very little rpm
increase,I have a volt meter in the system to register charging,very simple install and not expensive,I would recommend it to anyone,I have wired the three wire
also and this is a lot simpler and you don't need a diode in the system.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top