3 wire alternator

Phil in Jackson · Feb 4, 2015

On the diagram just 8ns 12v conversion
Ford 8n sn 263844 & up with an ammeter what do the numbers 1 and 2 mean on the alternator. Thanks Phil

JMOR · Feb 4, 2015

1-Excite
2-Sense

Phil in Jackson · Feb 4, 2015

can you explain where they go. I got a new wiring harness from just 8ns and I don't think they have the excite and sense on the harness.

JMOR · Feb 4, 2015

You don't use either if a 1-wire alternator. If you bought their kit, it is a 1-wire. 1/2 terminals will be present whether 1-wire or 3-wire.
What do you have?

HCooke · Feb 4, 2015

Google 'wiring diagrams by JMOR' This site will not let me post a link.

Just 8Ns and this site sell a 12 volt conversion kit and wiring harness that is one wire to the alternator and ignores the '1' and '2' connectors. I have one on a 9N and it works just fine.

kylemorley · Feb 4, 2015

Definitely a job for jmors fine diagrams!

It takes a couple of minutes longer to wire up a 3-wire alternator, but it is well worth doing because it is a little more efficient, and when the alternator needs replacement you can go down and buy a cheap standard rebuild at any bargain autparts store, rather than hunting around and paying extra for one modified to be one wire.

Phil in Jackson · Feb 4, 2015

I have a 3 wire Delco with wires coming out of 1 and 2, not a plug in type like on my other 8n.

JMOR · Feb 4, 2015

(quoted from post at 13:10:42 02/04/15) I have a 3 wire Delco with wires coming out of 1 and 2, not a plug in type like on my other 8n.

eally?! Wires & not a plug onto two spades? Never seen or heard of such thing. Picture?

Dell (WA) · Feb 4, 2015

Phil.......JMOR's drawings are pretty good ...but... they must not be answering yer questions. 12-volt alternators have 3-connections. A BIG one on the back end that goes to the BATTERY + terminal. (usually part of the amp meter board) #1 is switched EXCITE so you can turn yer engine OFF. Usually yer IDIOT lite on yer BelchFire-V8 does that. #2 is remote sense. Keeps yer alternator from outputtin' 17-volts and BOILING the water outta yer battery. Unlike yer 6-volt genny, 3-terminal alternators once excited will charge at idle.

You do know that S/N 263844 is when Ford changed from weird 4-nipple front mount with genny on right side to the 5-nipple side mount with genny on LEFT side, don't you?

In either case, change the roundcan ignition coil to NAPA IC-14B and use NO resistors. It should be intuitively obvious change yer headlites and tail lite to 12-volts. Don't haffta change yer 6-volt starter motor 'cuz one of the "benefits" of 12-volts is yer starter motor really "whizzes" for faster and eazier starting. ........HTH, Dell a 12-volt advocate for the right reasons

Phil in Jackson · Feb 4, 2015

Picture

Phil in Jackson · Feb 4, 2015

picture

Phil in Jackson · Feb 4, 2015

I have a no resistor coil

Ultradog MN · Feb 4, 2015

The easiest diagram I have seen for a 10SI is the one linked to below.
Though the page is about LanRovers, it has some interesting information about alternators in general too.
Scroll about 3/4 of the way down the page for the diagram.
I wrote to the web page owner and thanked 'him' for such an easy schematic to follow.
They wrote back and said you're welcome, then proceeded to tell me 'he' is a woman.
click here.

JMOR · Feb 4, 2015

(quoted from post at 13:58:33 02/04/15) picture

omeone just "cheaped" out & instead of the two socket connector, simply slipped two spade type wire connectors over the alternator's VR spades. If you don't short to case, that works, too.

rvirgil_KS · Feb 4, 2015

(quoted from post at 18:58:33 02/04/15) picture

#2 pin (black wire) connects to output. (big stud with red and white wires)

#1 (yellow wire) connects to coil side of ignition switch through an "idiot light" or diode. Diode should be rated at least 3 amps at 50 volts. Radio shack 276-1661 had good heavy leads. Marker band on diode toward alternator.

Output of alternator to ammeter.

For about 3 bucks you can get a plug with short wires from auto parts store and simplify things for now and avoid confusion later if both spades are disconnected from alternator. Connect #2 wire on plug to output stud, then you only need one added wire for #1.

kylemorley · Feb 4, 2015

The plug is intended to make it easy to hook up, and harder to hook up the wrong way, but the connectors in the hole are standard spade connectors, so many of us who forgot to swipe the right plug at the junkyard or can't find one at the auto parts store just use two spades and hope we will remember which is which (a poor bet, in my case).

Duner Wi · Feb 4, 2015

From the web site.
The Number two "sense" terminal is often connected to the BATT. terminal at the back of the alternator. This is the simplest connection and the LEAST desirable since it is measuring the alternator output and not the voltage at the load connections.
UD you have posted a link to correctly wire an alternator. Do you think one person will listen???
I doubt it.

JMOR · Feb 4, 2015

No need to in these tiny tractors (wire lengths) & tiny loads for drops. Just additional potential problems for connections & wiring complications. Difference will never materialize. Now in your 2015 with 100+ amperes loads, that is another chapter.

phil_n · Feb 5, 2015

Here's another link with some good stuff on alternators. http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html

JMOR · Feb 5, 2015

(quoted from post at 02:18:26 02/05/15) Here's another link with some good stuff on alternators. http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html

Good illustration of the "why" remote sense & it certainly won't hurt anything on little tractors if you are so inclined to use it.

Duner Wi · Feb 5, 2015

If I asked the question on how to wire my side mount 8N with Delco 10 or 12 SI alt I would like to at least have the option to know the most correct way. Looping the S2 to the Battery lug works but if you are going to operate a sprayer motor, light bar. winch motor, or something else running the sense wire farther away from the alt.
like GM did is a better option cause now it senses more accurately the voltage requirements.

Ultradog MN · Feb 5, 2015

[i:654c4848f0]"Do you think one person will listen???"[/i:654c4848f0]

To Me? The intransigent, non-electric guru?
Probably not.

JMOR · Feb 5, 2015

(quoted from post at 10:24:34 02/05/15) If I asked the question on how to wire my side mount 8N with Delco 10 or 12 SI alt I would like to at least have the option to know the most correct way. Looping the S2 to the Battery lug works but if you are going to operate a sprayer motor, light bar. winch motor, or something else running the sense wire farther away from the alt.
like GM did is a better option cause now it senses more accurately the voltage requirements.

ell, Duner, as I said "if so inclined", but I'll not be altering my illustrations, because the tenth or two volts (do the math) simply does not matter & falls very, very easily within the GM recommended battery voltage of battery while on charge, and two, most conversion kits us the one-wire alternator anyway (an even closer to alt #2 to output loopback). Do as you please, be happy, re-work all my diagrams & re-issue if you like. Enough!

greywolf224 · Feb 5, 2015

:lol: Pick a midway point. How's about the junction block. :lol:

Those heavy current draw items listed (i.e winches and light bars) would be more than what this alternator can keep up with if constantly used so I really don't think it would matter where the sense wire is connected.

3 wire alternator

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