(800) 853-2651
SHOP NOW

Another Delco 10SI question

Z

Zachary Hoyt

Well-known Member
The alternator I was working on when I had the other question is
now installed and working. I put it on the 300 when the alt that
was on there stopped working correctly. The one that quit
stopped showing a charge on the ammeter, but when I put the
cheap digital multimeter I have on the battery posts or on the big
terminal on the alt I was getting a reading between 15 and 18
volts that jumped around. I took it off and put in a VR and
replaced the rectifier, which had loose insulation around the
three little studs. The diode trio looked okay and the brushes
were still good. When I put it back on the tractor it was still
doing the same thing so I took it off and put on the newly rebuilt
one. I would like to get this alt fixed and put it on an Allis C that
I am working on. I am wondering if anyone can tell me which
parts would cause it to behave like that, or if I should just get a
full rebuild kit and replace everything. Any advice will be much
appreciated.
Zach
 
You said the diode trio "looked good." Did you actually test it? My experience from field repairs over 30 years is that the diode trio is the most common failure on those units. It should go without saying that all the connections should also be clean and tight.
Good Luck and God Bless
 
I agree that it's the diode banks.

What I'd like to know is with the price of a reman 10SI why are you even messing around trying to rebuild them? My cost on a life time warrenty one without an exchange is about 42 bucks. Parts to rebuild (to me thats brushes, rectifyer/VR, diodes and bearings) are real close to 30 bucks buying the higher end (all I use) parts. To me it wouldn't be worth the trouble, I think the core is worth about 7.50.

Rick
 
Did you clean the slip rings? Are the brushes and rheir springs good so brushes making good contact on the sliprings?
 
Thanks. I don't know how to test the diode trio, it is easy to replace so I will do that. I have found that it costs me about $50 or more to buy a reman and that there is no guarantee, but maybe I need to go to a different shop or order one online. I can get a rebuild kit for $25 that has almost everything and has free shipping, so that is what I have done so far.
Zach
 
Use the OHM meter on your Multitester. Should have continuity through your diodes if they're any good.
 
Diodes have continuity in one direction, and none in the other direction. You should get a reading of 0 Ohms, then "infinity" Ohms after you swap the probes from end-to-end.
 
See if you have an O'Rilery's or NAPA near you and get a price on what they are selling. We have a farm store near us that sells the rebuild kits. Pretty poor quality IMO, don't know what you are getting. O'Rileys list them on line for a reman at less than 50 dollars with a limited life time warrenty. Don't know what shipping would be if you are not close enough to pick one up.

Rick
 
Does the meter work differently when testing a known good system?

Your cheap digital multimeter may be the reason you are seeing the voltage jump all over. The regulator also works digitally so the current applied to the rotor field coil is either maximum or nothing. The output voltage is determined by the amount of time voltage is applied through the bushes verses the amount of time there is no voltage applied. As a result the output voltage from the alternator is also varying constantly. The regulator switched so rapidly that an analog voltmeter cannot react fast enough to show the change in voltage from the alternator output. Your digital meter continually takes a "snapshot" of the voltage and shows it on the display. The capacitor in the alternator is supposed to smooth out the voltage spikes but even with a good capacitor you are able to see the wave pattern in the output voltage when it is displayed on an oscilloscope.
 
You must log in or register to reply here.

Similar threads

formerly ny bill
another tractor ready for plow day
Replies
6
Views
898
formerly ny bill
formerly ny bill
S
Another 8n Charging Issue
Replies
12
Views
466
sfrye5853
S
jon f mn
Weekend project
Replies
1
Views
624
john in la
J
J
International 786 charging help
Replies
15
Views
652
used red MN
U
D
1963 Ford 4000 Select-O-Speed, PTO slipping.
Replies
2
Views
189
LarrySTN
L
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