Farm Equipment - Generator Testing

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Generator Testing

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=179135
Printed Date: 07 May 2025 at 4:27am
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Topic: Generator Testing

Posted By: Tyee II
Subject: Generator Testing
Date Posted: 17 Mar 2021 at 11:59pm

My knowledge of generator systems is very minimal. I have a D 12 series 3 that recently quit charging and a D17 Series 3 Diesel that I replaced a generator and cut out on several years ago and it quit charging within the first year. Is there a method of testing on the tractor ? Is there a setup procedure to match the generator and cutout if I end up replacing ? Neither are charging at the battery does the ammeter show any movement.

Replies:

Posted By: HD6GTOM
Date Posted: 18 Mar 2021 at 12:36am

Contact Steve at B&B custom circuits. He has HD regulators and its a good chance he can get you close to fixing your problem. I bought a regulator for my series 4 diesel. It was far heavier than the one I took off. It came with clear directions for the complete installation.

Posted By: john(MI)
Date Posted: 18 Mar 2021 at 3:13am

Put an alternator on them and be done with it.

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D14, D17, 5020, 612H, CASE 446

Posted By: jaybmiller
Date Posted: 18 Mar 2021 at 6:05am

yes, 2 skools here... haveit replaced by Steve or upgrade to alternator

My thinking...If the tractors are for show, use generators if needed in the field, install alternators.

All my D-14s have 'CS-130' alternators on them. Smaller than the old 'big10' units,lots of amps, reliable, and CHEAP( $10 scrap yard ). Just be sure to get the connector too !

What ever you do, be sure to remove ammeter,replace the fibre insulators with nylon ones ! Minor 'corrosion' there allow battery to slowly discharge.

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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

Posted By: DonDittmar
Date Posted: 18 Mar 2021 at 6:10am

1. Make sure the A terminals on gen has at least battery voltage with the tractor running. This test ensures the cut out in the VR is closing connecting the gen to the battery

2. Unhook the F terminal at the gen that jump it to ground. This should force the gen to go to "full field" and it should begin charging. If it does the problem is in the VR and/or wiring. If it doesnt you at least have a problem with the gen and it will have to come off for further diagnosis. May just need to be cleaned up and a new set of brushes or could be a lot more. Once the issue with the gen is fixed repeat step 2 to verify VR and wiring is working

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Experience is a fancy name for past mistakes. "Great moments are born from great opportunity"

1968 D15D,1962 D19D
Also 1965 Cub Loboy and 1958 JD 720 Diesel Pony Start

Posted By: steve(ill)
Date Posted: 18 Mar 2021 at 8:58am

Don is right... Only 2 wires on the generator. I take a short wire with alligator clip and jump the "F" terminal to ground.. That bypasses the regulator grounding function l~~ight switch resistor~~ and you should get POWER (volts) out of the generator going to the reg ~~cutout.~~.

Check the voltage into the regulator ~~cutout and out of the cutout to see if the cutout CLOSED.~~(with "F" jumped to ground)... You dont even need to take either wire off the generator.

Steve in NJ Is right.. there is no "cutout" box. It should be a voltage regulator on a D series.... Same test... Ground the F terminal of the generator and see if you get voltage between the " A" or "G" terminal ( into the regulator) and ground...If so, see if you have voltage on the "BAT" terminal out of the regulator

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Like them all, but love the "B"s.

Posted By: Coke-in-MN
Date Posted: 18 Mar 2021 at 2:09pm

Might find some info on here
http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm" rel="nofollow - http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm

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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."

Posted By: Steve in NJ
Date Posted: 18 Mar 2021 at 3:35pm

The correct way to find out what's goin' on is remove the Generator, have a local rebuilder run some load tests on it and see what it's doing. OR if you would like to sent it this way I can check it out for you on the 881 machine and then tear it down to access it and see what is going on inside. If you're running the OEM 6VPG system yet, a nice upgrade from the cutout is to move to a HD Voltage Regulator to regulate the charging chores. If I remember correctly, I don't think any of the "D" series Tractors had the 3 position Headlight/Charging switch like the earlier Tractors had. Also, make sure the VR is grounded correctly. In a lot of cases, the ground is lost and the charging stops. Make sure the chassis of the VR is clean and free rust to make a good ground to the Tractor.

Steve@B&B

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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife

Posted By: Leadoff
Date Posted: 19 Mar 2021 at 12:55am

Tyree II

I improved my D17 charging performance by cleaning the points inside the Voltage Regulator. A film had formed on the points contact surfaces.

I second the previously noted comments on charging system components grounding. The Generator connection to the tractor, battery terminals, VR connection to the tractor, and all wiring connections needs to be shining

Good luck with your project

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1963 D17D Series III. 1965 D15 Series II. 1965 D17 Series IV. 1975 185. 1978 716H. 1979 716H. 1965 780 Harvester/1R&DC. 1957 Model 73 SC 4 Furrow Plow