One wire alternator
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=170327
Printed Date: 31 Oct 2025 at 9:22am
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Topic: One wire alternator
Posted By: 1947WC
Subject: One wire alternator
Date Posted: 20 Apr 2020 at 1:41pm
| Is there any way to test a 1 wire alternator with a test light it's a positive ground. |
Replies:
Posted By: Jim.ME
Date Posted: 20 Apr 2020 at 3:36pm
| I am guessing you are talking about checking alternator output. About the only thing I can see a test light will tell you is there is power at the alternator output stud, which it should have at all times on a one wire alternator. You need a voltmeter to see if the voltage changes when it is running. Positive or negative ground makes no difference in that. I have to ask this, Are you sure it is actually a positive ground alternator? |
Posted By: Dakota Dave
Date Posted: 20 Apr 2020 at 5:57pm
| Take it off and take in and have tested at the auto parts store. If your alternator has been hooked up POS ground your going to need a new one any way. The diodes are blown and it'll have no output. There are specitly shops that will make a POS ground alternator but they are very expensive. Negative ground became the world standard even before 12 volts became the standard voltage. |
Posted By: DiyDave
Date Posted: 20 Apr 2020 at 5:59pm
Check with a volt meter, at battery. volts running, vs volts not running... ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: 1947WC
Date Posted: 20 Apr 2020 at 9:01pm
| Thanks Jim.ME |
Posted By: 1947WC
Date Posted: 20 Apr 2020 at 9:08pm
| Thanks Diy.Dave |
Posted By: 1947WC
Date Posted: 20 Apr 2020 at 9:13pm
| Thanks Dakota.Dave |
Posted By: Adam Stratton
Date Posted: 20 Apr 2020 at 9:24pm
| Touch something metal to the bearing on the back of the alternator. If it magnetized, it is charging, if not it isnt |
Posted By: 1947WC
Date Posted: 22 Apr 2020 at 1:09pm
| I'll try that. Thanks Adam. |
Posted By: jaybmiller
Date Posted: 22 Apr 2020 at 1:16pm
|
if, IF, the test light was an LED, then yes.....though everyone has a voltmeter. Just be sure the test leads are in properly(red2red,bl2blk) !!! 99.44% of all alternators are NEG ground BTW.... ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |