JD 50 Single Wire Alternator Wiring

Steve in IL · Oct 25, 2020

Anyone have a wiring diagram for the installation of a single wire alternator onto a JD 50? Previous owner installed it, but it does not seem to be working. Amperes gauge does not move, and battery slowly runs down. Suggestions?

buickanddeere · Oct 25, 2020

Install the proper 20 amp generator .

old · Oct 25, 2020

Battery that runs down tells me the alternator has a problem. Wiring one is so simple a well trained monkey could do it. Wire from the alternator goes to the amp gauge. The side that stands alone the other side has the power and ignition hooked to it

Steve in IL · Oct 25, 2020

Hmmm. That was helpful.

rvirgil_KS · Oct 25, 2020

Assuming it is the common Delco alternator, As Old says, wire from large output post on alternator goes to ammeter.

If battery runs down in relatively short time it could be bad battery or defective alternator. If it takes a couple to weeks to go down that can be the nature of some of the one wire alternators.

Not charging could be too large a pulley on alternator causing it not to build enough rpm to kick on.

You might try momentarily jumpering the #1 edge pin to the large output, or just short across the two pins. If that makes it charge you could connect it as a 3 wire configuration by running a wire from output of on-off switch with isolating diode, resistor, or lamp in the line to the #1 pin. The isolation is to preventing engine from continuing to run with engine turned off.

One advantage of the internal regulated alternator is that you got rid of a notoriously troublesome generator regulator.

buickanddeere · Oct 25, 2020

(quoted from post at 16:22:14 10/25/20) Hmmm. That was helpful.

An alternator on a two cylinder is particularly butt ugly . Connecting A generator seems to be less confusing than an alternator .

Jeff Oliver · Oct 26, 2020

Wiring one is pretty easy. Like they say just run the wire to the Amp meter. If battery is draining I would have both battery and alt checked. If they are both good put a switch between the alternator and the amp meter. Bought a Super 88 Oliver that had that problem. They descibed it as bleeding back through alternator, whatever it was doing if you turned the switch off when you stopped tractor the battery would say up. If you left it on the battery would drain down .

Kansas rhody · Oct 26, 2020

Should be fairly easy to check to see if the alternator is working, just use your voltmeter to see how many volts its putting out, should be well above 12.5 . If that is working next step is to check your battery, many chain auto stores can test it for free, hopefully it is something easy like your battery is just toast, if so buy one with the most cranking amps that will fit under the seat, good luck

buickanddeere · Oct 26, 2020

Why not use a diode instead of donking around worth a switch ?

Steve in IL · Oct 26, 2020

Ok... Thanks for the input. Been trying to learn about this one-wire alternator option. Quick full story...
Just replaced battery, as old one was bad. Decided to also replace alternator, as old one was drenched in power steering fluid (leak now fixed). Hooked everything up, and amperage gauge does not budge. Googled new alternator part number, R111621B (Reman Ultima 63amp, the one that the counter guy at O-Reilly's said was what I needed). Not able to be set up as one wire. Considering:
a. Take alternator back and get a one-wire capable one. Concerned that spinning speed might be too slow to self excite one wire though. or...
b. Use the alternator I already have, and rewire for 3 wires. Doesn't look too tough. Might work better at low speeds?

Anyone have experience with one wire systems at slow speeds?

Thanks, Steve

wore out · Oct 26, 2020

(quoted from post at 08:02:40 10/26/20) Ok... Thanks for the input. Been trying to learn about this one-wire alternator option. Quick full story...
Just replaced battery, as old one was bad. Decided to also replace alternator, as old one was drenched in power steering fluid (leak now fixed). Hooked everything up, and amperage gauge does not budge. Googled new alternator part number, R111621B (Reman Ultima 63amp, the one that the counter guy at O-Reilly's said was what I needed). Not able to be set up as one wire. Considering:
a. Take alternator back and get a one-wire capable one. Concerned that spinning speed might be too slow to self excite one wire though. or...
b. Use the alternator I already have, and rewire for 3 wires. Doesn't look too tough. Might work better at low speeds?

Anyone have experience with one wire systems at slow speeds?

Thanks, Steve

All you need to do is keep the (good) standard 3-wire alternator you have, jumper it's #2 terminal to it's output stud for voltage sensing, then wire the #1 terminal to the ignition switch with an indicator light using a #194 lamp (or equivalent), a diode (1N5408 is a great choice), or a 50 Ohm 10 Watt resistor in series with the wire.

It will excite at low RPM, and you will be well pleased with the outcome, IMHO.

James Howell · Oct 26, 2020

"[b:654c4848f0][i:654c4848f0]keep the (good) standard 3-wire alternator[/i:654c4848f0][/b:654c4848f0]"

Agree.

"[b:654c4848f0][i:654c4848f0]jumper it's #2 terminal to it's output stud for voltage sensing[/i:654c4848f0][/b:654c4848f0]"

"[b:654c4848f0][i:654c4848f0]wire the #1 terminal to the ignition switch with an indicator light[/i:654c4848f0][/b:654c4848f0]"

JD 50 Single Wire Alternator Wiring

Steve in IL

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buickanddeere

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old

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Steve in IL

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rvirgil_KS

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buickanddeere

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Jeff Oliver

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Kansas rhody

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buickanddeere

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Steve in IL

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wore out

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