D Grader Voltage Regulator
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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=211185
Printed Date: 29 Sep 2026 at 12:13am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: D Grader Voltage Regulator
Posted By: Pgriswd
Subject: D Grader Voltage Regulator
Date Posted: 25 May 2026 at 2:19pm
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Hello All Just rebuilt a D grader and want to make sure we wire the alternator and voltage regulator correctly. The alternator is a 2 pin with F and S. The Voltage regulator has Gen on top, F, Batt, L on the bottom. Could someone let me know there to connect . Thanks |
Replies:
Posted By: Les Kerf
Date Posted: 25 May 2026 at 3:53pm
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Is this an existing alternator/regulator combination that previously worked together or are they new components? I ask because the markings on your regulator seem to indicate that it may be for a generator rather than an alternator. They need to be matched correctly.
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Posted By: Pgriswd
Date Posted: 25 May 2026 at 4:00pm
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Hello Les Yep new components. |
Posted By: steve(ill)
Date Posted: 25 May 2026 at 4:07pm
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F and S stand for FIELD and SENSOR... normally that means you have an INTERNAL VOLTAGE REGULATOR.... I assume this is a DELCO 10 SI alternator ?? ...... who told you that you needed an external voltage regulator ??
your 4 terminal voltage regulator sounds like a GENERATOR regulator ? something like this.... if you have a diesel, forget the coil and plug part..  ------------- Like them all, but love the "B"s. |
Posted By: Pgriswd
Date Posted: 25 May 2026 at 4:49pm
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Hello Steve Original set up had a voltage regulator so assumption was I needed one. Wiring was a mess and not even sure the regulator was hooked up. I think what you have is what needs to be done. I do have a 10si alternator. Thanks for the info |
Posted By: steve(ill)
Date Posted: 25 May 2026 at 5:49pm
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i use the 10 ohm 10 watt resistor in the sensing line.. Some people use a DIODE and others use an IDIOT LIGHT on the dash...... I got the resistor idea from a Service Bulletin in 1975 DELCO manual on how to bench test the alternator..
your original voltage regulator was probably for the original GENERATOR... and was abandon in place when the new Alternator was installed... ------------- Like them all, but love the "B"s. |
Posted By: Jim.ME
Date Posted: 25 May 2026 at 6:38pm
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The 10DN alternator with an external regulator was commonly used as the step from generator with regulator to alternators. I agree his regulator terminal designations appear to be a generator regulator. The drawing posted for a 10SI is wired correctly; however, the labelling of the spade terminals is wrong. The #1 spade (left) is the excitation terminal, not R (sensing feedback to the regulator). The #2 (right spade) is the sensing terminal, Not F (field).
The Delco 10DN alternator used an external regulator. The two terminals where the small wires plug in are labeled R (left spade) (controls the regulator's turning an indicator light off when the alternator is charging) and F (right spade) for field excitation. These spade terminals are in the opposite locations from a 10SI's spade terminals. |
Posted By: steve(ill)
Date Posted: 25 May 2026 at 6:55pm
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youir right Jim... i have missed that for several years... the wires are RIGHT and the NUMBERS are right... but the R and F label are reversed !! ------------- Like them all, but love the "B"s. |
Posted By: Pgriswd
Date Posted: 25 May 2026 at 7:07pm
| Thank you guys for making this easier. Appreciate yall |