TRACTOR PARTS Allis Chalmers Case & David Brown Farmall & International Ferguson Ford & New Holland John Deere Massey Ferguson Massey Harris Minneapolis Moline Oliver & Cockshutt Kubota / Yanmar

TRACTOR MANUALS

Allis Chalmers	Case	Farmall IH	Ford 8N,9N,2N	Ford
Ferguson	John Deere	Massey Ferguson	Minn. Moline	Oliver

Tractor Talk Discussion Forum

One-Wire Alternator to 3-Wire

Welcome Guest, Log in or Register

Author

Gene-AL

04-19-2007 19:57:27

Report to Moderator

I've read many posts about one-wire and 3-wire alternator setups, but it was never completely clear whether or not a 'one-wire' alternator could function the same as a 3-wire if an 'Idiot light' ignition-switched circuit was added. I tried it and it did work - at least with this one alternator.

Original tractor charging system was an alternaor or generator, with an external regulator, but that had been replaced with a GM style alternator sold as a 'one-wire' unit, which required the engine to be reved up to start the charging process.

Removing the original tractor voltage regulator plug from regulator and terminating the switched 'Idiot light' wire at the #1 terminal on the 'one-wire' unit worked correctly. Charge-light goes out immediately after engine is started. Charging proved by battery voltage slowly rising above 13V and screwdriver test for magnetism at end-center of alternator housing. Results may vary with some 'one-wire' units - don't know the answer to that.

[Log in to Reply] [No Email]

John T

04-20-2007 10:00:22

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

Gene, I usually use a 10 ohm current limiting protection resistor to excite those 3 wire alternators (on the lil No 1 terminal) but an "idiot light" serves the same purpose allowing sufficient excitation current and voltage to get her to start charging. HOWEVER use incandescent cuz if its like an LED it may be of to high resistance and not provide sufficient current. Some One Wires require a higher RPM to excite and some draw a small trickle discharge, I like the GM 10 SI 3 wires converted as above to function similar to a one wire.

John T

[Log in to Reply] [No Email]

Gene-AL

04-20-2007 12:02:53

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to John T, 04-20-2007 10:00:22

John T., The tractor was already equipped with a 12V charge indicator lamp which, fortunately, was of a suitable size and also wired to the old alt/gen connector plug via one terminal on the old VR plug. After checking the manufacturer's electrical diagram, it took only a few minutes to unplug the original voltage regulator and then add a 6" wire extension with a terminal lug at the alternator end to make the change over(JD-2120).

[Log in to Reply] [No Email]

Gene-AL

04-20-2007 08:18:55

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

Yes, the charge-indicator light went out immediately when the diesel engine started, indicating that the alternator was being excited - no more reving up and then hoping it was charging as before (no Ammeter on this tractor). It is probably a remanufactured 37-Amp 'one wire' alternator.

Jon, thanks for the clearing that up.

[Log in to Reply] [No Email]

Jon Hagen

04-20-2007 06:06:13

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

I build both one wire and three wire Delco alternators for what ever best fits the application. The brand of one wire regulators I buy have instructions with them that they can be used with an alt warning light by connecting it to the #1 regulator terminal. Atleast with this brand, you do not need to add the #2 sense wire, although I have installed it and they work fine either way. The box of regulators came with instructions saying that there is no problem using these regulators in any application where a charge light or lower excite rpm is desired.
One trap not to fall into is buying more "one wire" alternator than you need, the smaller the amp output, the lower the excite rpm. A 37 amp "0ne wire" Delco will excite at about 1/2 the rpm of a 72 amp "one wire" unit.

By the way, there have always been FACTORY "one wire" Delco alternators. The "one wire" version of the Delco 27SI have been used in truck industrial and marine applications since the 70's.
The factory Delco"one wire" regulator parts fit right into the smaller 10SI-12SI alternators, although I rarely use them. They cost 8 times as much as an aftermarket "one wire" regulator. They have an externally adjustible voltage adjustment which I feel has little value for the average user.

[Log in to Reply] [No Email]

cj3b_jeep

04-20-2007 04:57:53

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

A one-wire alternator canot be used with an idiot light, only an ammeter or volt meter, my old Jeep is set up with a one-wire, which has to self excite just above idle, right around 700 rpms. It used to kick in at about 1,000 rpms, but I took it to a generator shop and they did something to it to make it kick in lower. The three wire version excites via the battery. Idiot lights are a strange thing, having power coming in one side from the battery via the key switch, and ground coming from the alternator, once the alternator is charging, it sends a second positive to the light, turning it off. All-in All, I think the three wire is a better setup, and also, if you have to replace one, it's much easier to find the three wire.

[Log in to Reply] [No Email]

jpl

04-20-2007 02:23:52

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

sorry,i meant john t not bob, its early yet.

[Log in to Reply] [No Email]

jpl

04-20-2007 02:01:35

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

yes, mine kicks in at past idle now, no more revving it up.

[Log in to Reply] [No Email]

jpl

04-20-2007 01:56:49

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

I had a one wire on m, it quit charging, before you just revved it up and it charged, i had it hooked through the ammeter, (i hooked a small wire to # 1 terminal and then to ignition sw, then put a toggle switch in the wire betwwen switch and alt, i start tractor and hit the toggle switch and it excites the alt and it charges, must been bad self exciter, works fine now.) next time i;ll use a three wire and hook up as per bobs instructions in archives. now if i can figure how to mount a alt on 560 gasser i;ll put on a three wire this time.

[Log in to Reply] [No Email]

midlam

04-19-2007 20:03:49

Report to Moderator

Re: One-Wire Alternator to 3-Wire in reply to Gene-AL, 04-19-2007 19:57:27

does alternator also kick on at a lower RPM with the light connected?

[Log in to Reply] [No Email]

[Options] [Printer Friendly] [Posting Help] [Return to Forum] [Log in to Reply]

TRACTOR PARTS	TRACTOR MANUALS

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. [ About Us ]

Home | Forums

Copyright © 1997-2023 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy