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Old 06-07-2020, 09:24 AM   #1
ABento
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Default Generator

About ready to get the sport coupe out for a test drive and the generator wants to charge well over 15 amps, new battery, Optima, fully charged, new cutout, the old one would not function, this generator doesn't have an adjustable third brush, what do I have I see no numbers and it is an A generator, I'll post a picture.


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Aaron
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Old 06-07-2020, 09:33 AM   #2
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Default Re: Generator

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Originally Posted by ABento View Post
About ready to get the sport coupe out for a test drive and the generator wants to charge well over 15 amps, new battery, Optima, fully charged, new cutout, the old one would not function, this generator doesn't have an adjustable third brush, what do I have I see no numbers and it is an A generator, I'll post a picture.


Thanks

Aaron
Picture?
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Old 06-07-2020, 10:00 AM   #3
Badpuppy
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Default Re: Generator

An A generator has a third brush. 15 Amps charging will kill your battery quick.

What you describe is what a 12V alternator would do.
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Old 06-07-2020, 10:38 AM   #4
30 Closed Cab PU
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Default Re: Generator

Do not know much about alternators. Thought they had an integral regulator. Do they use a cutout? Asking since poster says he has a cutout.
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Old 06-07-2020, 11:11 AM   #5
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Default Re: Generator

Non Ford generator or maybe other brand? If it is a Model A generator, then it will have an adjustable brush or there is a problem with the ring it mounts on not allowing it to turn.

https://www.google.com/search?client...rd+brush+plate
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Old 06-07-2020, 11:43 AM   #6
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Had to go get a picture, it seems too big to post and I don't find the way resize it for here.
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Old 06-07-2020, 12:32 PM   #7
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Default Re: Generator

If it is an 'A' generator without the movable brush then maybe it was removed to install a voltage regulator. You could check that, but, with an internal regulator it shouldn't be charging that much for very long.

It sounds to me that you probably have a later generator that requires a voltage regulator.

To answer another question about alternators, no, not all alternators have an internal regulator. That is a newer thing, the old alternators all had external regulators.
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Old 06-07-2020, 01:06 PM   #8
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Default Re: Generator

The generator had a cutout on it when the car came in,when I got around to starting it the cutout didn't work so I got a new one, the old one and the gen were all painted black so it seems to be correct.
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Old 06-07-2020, 01:28 PM   #9
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Old 06-07-2020, 01:39 PM   #10
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Default Re: Generator

Have you taken the band off that covers the holes at the rear? Yes it looks like a Model A generator.

The 3rd brush is accessible under the band, not from the outside. Not trying to be a smart a##, just want to make sure you know.
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Old 06-07-2020, 02:39 PM   #11
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Default Re: Generator

I did remove the band and looked at the two brushes you can see, they looked to be in the fixed position, I was gonna remove it and take a good look at ti and I have a couple other ones just as cores I'll look at those also.
Never hurts to ask.
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Old 06-07-2020, 03:09 PM   #12
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Default Re: Generator

should be a third brush too for adjusting
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File Type: jpg gen 3rd bsh.jpg (27.0 KB, 32 views)
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Last edited by Gary WA; 06-07-2020 at 03:23 PM.
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Old 06-07-2020, 03:11 PM   #13
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Default Re: Generator

Was the cut-out you removed a true cut-out or a voltage regulator in a cut-out body? If it was a regulator it might not show indication on the ammeter if the battery was charged.
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Old 06-07-2020, 03:12 PM   #14
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Default Re: Generator

Are you relying on a good amp gauge or tester.Some of the repro amp gauges are made to just look like an amp gauge to fill a hole and do not show true.
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Old 06-07-2020, 04:25 PM   #15
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Default Re: Generator

If it uses a cut out , it has a third adjustable brush . The band must be removed , the brush gets adjusted through the side hole in the generator . Pushing down on the third brush raises the charging rate . The brush will need to be moved upward or raised to reduce the charging rate . You really need to look at a diagram of thje rear generator brush plate to see and understand how the third brush can be raised . I believe that Snyders and Brattons catalogs shows such diagrams . It is really not as difficult to adjust the third brush .
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Old 06-07-2020, 04:29 PM   #16
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Default Re: Generator

This picture may help.
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Old 06-07-2020, 04:33 PM   #17
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Default Re: Generator

The "third brush" is the one most directly in view as you look down into the generator with the band off. People are often unaware about how the brush is "adjustable" when those of us use that term. I'm not casting aspersions here, but your use of the words "when it came in" may mean you are repairing this problem for someone else or you are totally new to Model A's. In any event the brush itself is not adjustable nor is there any noticeable mechanism you should be looking for (like a screw driver slot) to effect an adjustment. Instead, the bracket that the brush is mounted on has a circular ring on it that allows the entire assembly to rotate around the copper commutator on the rear of the armature. Thus, the brush also moves around the commutator and this changes the charging rate. Your goal is to move the assembly in that arc around the commutator counter clockwise to the direction of the armature (with the front of the generator being the frame of reference). To be more specific, you want to move the brush assembly "up" in a direction that will bring it closer to the engine block to lessen the charge. (Moving the brush assembly clockwise and "down" toward the ground will increase the charging rate) This is done without the car running. If you can't do this with your fingers, you should be able to move it with a wooden dowel. Once the adjustment is made, go back in, start the car, and check to see if the ammeter is showing less than 15 amps. If so, your in the right direction and the ultimate goal, for regular daytime driving, is to get the adjustment to read 6-8 amps charge at driving speed. If nothing changes with your adjustment, I'd advise further examination of the generator for other issues. (If your attempts to move the brush still leave you scratching your head, you can take the back cover off one of your spare generators to understand the brush adjusting mechanism)

Good Luck, Bob Bader
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Old 06-08-2020, 07:10 AM   #18
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Default Re: Generator

The repro ammeters that the vendors have been selling for decades are pretty much junk. The one in my '28 pickup shows 12 amps when I start the engine but when I turn on the lights it goes to zero. I've been driving it for years this way with an Optima 6-volt battery and without any problems.
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Old 06-08-2020, 08:41 AM   #19
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Default Re: Generator

The generator in post 9 has a terminal at the front near the fan. Most that I've seen have the terminal behind the cut out. The wires for the buss, horn, & headlight switch are generally connected at the front. I'd be curious about what type of generator that is. Perhaps it's an early cylinder type generator from mid 1929 to mid 1930. I'm used to seeing the later unit.

It may have been modified if it has no 3rd brush. The Fun Projects cut out has been around for quite a while. It may have had one of those on it but it still would have to be a 3-brush type. John Regan had instructions to set the output at around 10-amps for those since they would regulate the current output down to nothing as long as the battery is in good condition. If a person replaces one then the generator would likely need to be readjusted.

Some replacement cut outs are just a heavy duty diode placed inside the can to look like an electromagnetic cut out switch.

Last edited by rotorwrench; 06-08-2020 at 08:53 AM.
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Old 06-08-2020, 09:29 AM   #20
ABento
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Default Re: Generator

Ahhh, I found the problem, I looked in the mirror, I knew these had the adjustable brush but its been a long time since I've delt with it, I've had my late 31 pickup since the early 70's, its not on the road but does function, anyway I did pull one of my cores apart and then saw what the adj brush was all about, that is a tough object to try to explain to someone how to adjust its not really obvious how to move it, and somehow I thought there was a screw on the back side to loosen the holder, not the case. Now my pickup has the the gen with the arm screw close to the pully, here are pictures of the other two I have. The new cutout is the mechanical type not the junk, same as the old one.

I did move the brush and got the rate down, at hwy speed it is now in the rang of 8 to 10, Optima says somewhere around 6, in town it is in that range, I may lower it a bit more.


Thank you for all the help


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