MTFCA Forum

Finally fixed the running issue with my T only to find that my generator isn't actually charging the battery. I guess I never actually bothered to check before this. Before I got the car it sat since '87, and I've heard talk about generators needing to be polarized, does this apply to the T? I do know it's the generator itself that has the issue, since my ammeter is in working order, the wiring is fine, I have a new solid state cutoff, and I'm measuring 0v from the output even when the engine is at 1000+ rpm. According to the manual I should clean the commutator, and I was planning on doing this either way, just wondering what else I need to know

Yes, clean the commutator, then read up on adjusting the third brush. If still not charging, send it to someone for a rebuild. Either Ron Patterson or Brent Mize. See the vendor information at the main club page.

Ye gads, a 100 year old electrical component of unknown service history! My advice is don't bother, just get a rebuilt generator from Brent Mize, or a similar experienced Model T generator rebuilder. And if your starter cranks over like an old tractor with a dead battery get a rebuilt starter too.

By the way, Ron does not rebuild generators anymore.

After cleaning the commutator, and charging does not register, contact : www.modeltstarters.com. .

Honestly, there are so many things that can go awry inside that generator it's crazy. It's quite easy to take out of the car. To fully inspect it, you really need to do so. Once it's out, you can jump your 6v battery to it and see if it turns like a motor. If not, then something is broken inside. If it does turn, then the null point might just need adjusting. A Google search on this should turn up Ron Pattersons excellent article on how to do this.

If it doesn't turn, then depending on your comfort level and tools you have, you need to 1) dig deeper or 2) get a rebuilt one. Of the 100's of generators I've rebuilt over the years, the main failures I see are: shorted field coils ( I only use new ones now), shorted armatures ( only about 50% of the armatures I see are useable and strong) & shorted brush plates. The last one is a major pain as good, useable brush holders are harder and harder to come by, and rebuilding a brush plate properly is no small feat. I'm actually getting new replica brush holders cast out of zinc right now. I just approved the engineering drawings last night and should see them in a month or so. It will be one of my small contributions to the hobby to help save these aging generators (and starters).

Jeff

Michael if your generator hasn’t been grounded out since it quit working it’s likely the generator has burned itself out. If you’re lucky it has not but at this stage of the game it may require a professional as others have stated. If you’re not going to act quickly on a rebuild then in an abundance of precaution, you definitely need to ground the generator out so you won’t do more damage. All you need is a wire from the post to a screw holding the cutout on. Just a thought!

I'm actually getting new replica brush holders cast out of zinc right now. I just approved the engineering drawings last night and should see them in a month or so. It will be one of my small contributions to the hobby to help save these aging generators (and starters).

Thank you Jeff! Just wanted to a knoweldge the time, effort and investment needed to research, design, develop, manufacture, stock and distribute parts and accessories for the Model T hobby. Helping others enjoy the hobby more is a big part of the motivation and rewards.

AdminJeff wrote: ↑

Sat Apr 06, 2024 11:37 am

Honestly, there are so many things that can go awry inside that generator it's crazy. It's quite easy to take out of the car. To fully inspect it, you really need to do so. Once it's out, you can jump your 6v battery to it and see if it turns like a motor. If not, then something is broken inside. If it does turn, then the null point might just need adjusting. A Google search on this should turn up Ron Pattersons excellent article on how to do this.

If it doesn't turn, then depending on your comfort level and tools you have, you need to 1) dig deeper or 2) get a rebuilt one. Of the 100's of generators I've rebuilt over the years, the main failures I see are: shorted field coils ( I only use new ones now), shorted armatures ( only about 50% of the armatures I see are useable and strong) & shorted brush plates. The last one is a major pain as good, useable brush holders are harder and harder to come by, and rebuilding a brush plate properly is no small feat. I'm actually getting new replica brush holders cast out of zinc right now. I just approved the engineering drawings last night and should see them in a month or so. It will be one of my small contributions to the hobby to help save these aging generators (and starters).

Jeff

Here's some of the information that Jeff referred too
Adjusting the Model T Generator Brushplate Null Point with the Generator Installed by Ron Patterson
https://modeltfordfix.com/adjusting-the ... patterson/
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Testing a Model T Generator Armature Using a Growler
https://modeltfordfix.com/testing-a-mod ... a-growler/
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Generator Repair or Replace discussion
https://www.mtfca.com/phpBB3/viewtopic.php?f=2&t=37795
--
Repairing a Common Model T Starter Problem by Ron Patterson
https://modeltfordfix.com/repairing-a-c ... r-problem/
another of Ron's --
Starter Bendix Repair

Thanks for all the info! I'll open the dust cover and clean the commutator and check the brushes, but if not I'll just send it out to get reworked

Ah, yup. I don’t know exactly what I'm looking at, but it doesn't look great and something smells slightly burnt. Definitely going to need to be rebuilt