28 volt alternator
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=72401
Printed Date: 17 May 2025 at 6:50am
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Topic: 28 volt alternator
Posted By: doctorcorey
Subject: 28 volt alternator
Date Posted: 25 Jun 2013 at 9:52am
| Anyone on here converted a hd7g or hd6g for alternator? If so, what alternator did you use? |
Replies:
Posted By: Coke-in-MN
Date Posted: 25 Jun 2013 at 11:45am
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You can find some of the older GM alternators used on heavy trucks that are the higher voltage . Unsure if you can convert something like the 10SI to higher voltage. ------------- 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: DMiller
Date Posted: 25 Jun 2013 at 12:12pm
| Corey, there are 24V alternators on the ebay site a lot, can do a google search for 24V alternator and will come up with a load of them. Ours are not 28V but 24V and positive ground. |
Posted By: Steve in NJ
Date Posted: 25 Jun 2013 at 12:18pm
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Depending on what the system was spec'd out for @ maximum amperage, some Delco 21 & 22 SI's fill the bill quite nicely on a lot of applications. If bigger amps/power are needed, a Bosch "AL" series Alternator would probably work quite well. All of the Alternators I mentioned adapt quite easily to industrial and AG applications. We have these large Alts in stock...
mailto:Steve@B&B" rel="nofollow - Steve@B&B
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Posted By: DMiller
Date Posted: 25 Jun 2013 at 12:49pm
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Charging system specs for the old 7G's was 15 amps, more would be better but as they don't often run lighting the lower rates work OK. Dave |
Posted By: doctorcorey
Date Posted: 25 Jun 2013 at 2:32pm
Thanks, boys. Yes it is for a 24 volt system. I'll be running floodlights on this machine but a truck alternator would probably work. I usually just charge both batteries before I start working the machine, as they provide 10-15 starts without replenishment, but I'm getting tired of doing that and battery life suffers if you don't keep them hot, as well as slow cranking. I'm lucky; my tractor usually starts by the third or fourth turn. 
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Posted By: Coke-in-MN
Date Posted: 27 Jun 2013 at 11:11am
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Have also seen individuals rig up a charging system for 2 - 12V batteries then have a solenoid that sends 24V to starter but runs everything else on 12V ------------- 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: doctorcorey
Date Posted: 27 Jun 2013 at 1:15pm
| I found a source for the 24 volt regulator (internal) for the 10si and 15si delco alternators. Now I can't remember my machine is positive or negative ground? |
Posted By: Coke-in-MN
Date Posted: 27 Jun 2013 at 2:42pm
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Make it whatever you want - just reverse the ground cable - then the wires on the amp gauge. ------------- 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: Ian Beale
Date Posted: 27 Jun 2013 at 5:01pm
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If I recall correctly Orangeman had a posting on alternators a while back.
I put a Bosch 24volt 50 amp one on our AC 45 grader. Was able to weld the Bosch 2-ear mount on a generator mount from a HD 11 (a straight surface rather than the more complex moulded one from the grader) and used the grader adjustment strap. The pulley from a Delco (ex HD 11) generator had the right bore for the alternator. That shaft doesn't use a key and I had to use a bit of Locktite to keep the nut on.
Had to change the system to negative ground, which seems to work ok.
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Posted By: doctorcorey
Date Posted: 28 Jun 2013 at 8:43am
| Change to negative ground, and the starter still turns the right way? |
Posted By: Ian Beale
Date Posted: 28 Jun 2013 at 4:07pm
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Seems to work fine and spin the same way |
Posted By: HD6 Merv
Date Posted: 29 Jun 2013 at 12:09am
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my 6ep had been changed to - earth. when I rebuilt generator and fitted new to me regulator just polarised it and every thing worked ok ------------- tits tyres and tracks they all cost you money |
Posted By: Lee Bradley
Date Posted: 29 Jun 2013 at 1:14pm
Because the field magnets are electro-magnetic opposed to permanent magnets the magnetic field is reversed when you change polarity and the starter turns the same direction. Some of the smaller starters use permanent magnets (garden tractors, lawnmowers, etc) and would reverse direction with a polarity switch.
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doctorcorey wrote:Posted By: doctorcorey
Date Posted: 01 Jul 2013 at 11:12am
| I finally remembered the polarity/rotation thing for field-coil type motors. Thanks for all the advice. |
Posted By: DMiller
Date Posted: 03 Jul 2013 at 8:59am
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Hey Corey, I have a fella in O'Fallon MO that will rework my old Delco Generator, he is parts and labor but a better deal I haven't found. We only need to charge batteries after a start so the 10/15 amps these made would be enough. Was told by Sydenstricker Tractor there is supposed to another rebuilder around Cuba, I did find Harold' Starter and alternator Svc, 573-885-7838, listings say there are others, may ask a local auto parts house if one nearby. |