(800) 853-2651
SHOP NOW

Alternator

Some need an idiot light in there. The altinator light in the dashbord of a car is needed to tell the altinator to excite itself. Had to add the idiot light when I switched over the two tractors or else you had to rev them up. Light works much better. Also smaller pulley if you can but most times the light will fixer up. See what the other guys say.
 
Most alternators need to spin at least 1500 RPM to charge. That has nothing to do with getting exciter current. Most alternators get exciter current as soon as the ignition is turned on. Note I am not talking about Delco SI series that have self-excite regulators swapped in.
 
That's a more common complaint on a "one wire" versus the so called "three wire" units in which case you supply initial excitation coming from the battery. Without the external source the alternator has to spin enough to produce its own excitation.

John T
 
Some you do, and some you don't. Some engines will start at a low idle and you need to bump it a little to get the alternator going. I suppose the alternator/crankshaft speed ratio is not a constant on all machines.

I have a little 3 cyl diesel engine I bought about a year and a half ago. I discovered I had to wind it wide open to get it to charge. Last winter I put it in the shop to fix it. I found lots of grease/crud in the alternator. Then corrosion under that! I got a new alternator, but it wouldn't work. Took it and had it tested. It wasn't getting excited. Turned out a diode, looking just like a mini fuse, was missing from the fuse panel. So how was the old alternator working at all? I assume vibration and some wild voltage from the wide open throttle, with all that crud, let the alternator excite itself. Mystery?
 
I am really glad that I don't have the alternator issues that many of you have. Almost every tractor I have ever bought to keep (or fix and sell), I converted to one wire alternator. All start charging at low rpm and none pull the battery down if left connected. One thing that probably many do not address is wiring. On most any tractor I convert, the first thing I do is strip every wire off it and start over. I solder every connection and cover with heat shrink tubing. It's a little more trouble and expense up front, but the dependability is priceless to me. Just my $.02.
 
IH used a 25 ohm resistor in excite circuit on the larger frame 66 series diesel tractors when they switched to the internal regulator 10 SI delco alternator. Soon after, they offered a 10 ohm resistor if customer complained about having to rev engine too high to start charging. They also used a separate wire to voltage sensing number two terminal direct back to main battery cable at starter for better voltage regulation than running to out put lead at alternator.
 
I've had the same experience with 1 wire alternators all (8 different tractors) start charging as soon as the tractors start and work great.Ever notice those that go on and on about the why
the one wire alternators don't work are people that don't use them? I get mine from DB Electric for about $60 for a 62 amp and they all have done well.
 
Hello John T,

You are right about the spinning of the alternator. I asked a GM factory rep what was the speed ratio, between a 1 wire alternator and the engine speed. He promptly answered: 2 5/8 faster then the engine speed. That was for a class8 truck application. Can't be that much different for other applications. In the case of an alternator, pulley size-speed does matter!

Guido.
 
(quoted from post at 08:00:55 01/29/18) I've had the same experience with 1 wire alternators all (8 different tractors) start charging as soon as the tractors start and work great.Ever notice those that go on and on about the why
the one wire alternators don't work are people that don't use them? I get mine from DB Electric for about $60 for a 62 amp and they all have done well.
Click to expand...

My 1 wire alternator starts charging before the engine has started. You have to have the right VR.
 
You must log in or register to reply here.

Similar threads

K
Farmall M charging issue - must rev engine for charge
Replies
12
Views
532
Turkeyfoot
Turkeyfoot
G
1980 Ford 445 diesel tractor new alternator output only 12.28
Replies
5
Views
249
Texasmark
T
grandpa Love
Alternator issues
Replies
14
Views
657
Rich'sToys
R
R
john deere 4020 12 volt conversion problem
Replies
2
Views
190
Jim.ME
J
K
Over voltage causing misfire
Replies
8
Views
1K
used red MN
U
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.

Copyright © 1997-2024 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

Back
Top