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Old 09-30-2012, 04:12 PM   #121
sturgis 39
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Default Re: Is There An Electrician In The House?

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Originally Posted by joeypoconos View Post
Call me crazy but;

Just re-installed the generator and hooked everything up. Changed out the cut-out to the one that was originally on the car. For the heck of it I got out the multi-meter and checked voltage.
At idle 6.2 everywhere except armature side of cut-out 0 volts
At high idle 6.2 all around, 0 at armature side of cut-out
Let her run at high idle and checked again. 6.2 everywhere except armature side of cut-out. 0 volts.
My electricity challenged brain tells me A) Bad cutout? B) bad connection at battery side of cutout? C) all of the above? Or, D) what the heck is going on????

Joey

If there is no voltage on the armature side of the generator when the engine is running, than the generator is not putting out when the engine is running. You did not paint the generator after it was tested and there is not a ground for the generator.That darn paint is a good insulator when you do not want it to insulate and is not a good insulator when you need a little luck.

I am still waiting for Ford Garage to reply about voltage at the cutout. I could be 180 degrees off on this stuff.
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Old 09-30-2012, 04:14 PM   #122
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Default Re: Is There An Electrician In The House?

sturgis - More than likely I'm the one that's confused. I was indicating that there was no voltage at the armature side of the cutout with the car running at fast idle. Heretofore, that was not case. That led me to conclude that either the cut-out is defective or the battery is not sufficiently drained to call for a charge. I suspect it's the later as the voltage reading at the battery is 6.3 and the at the batter side of the cutout 6.3 which is probably not enough to cause the cutout points to close. In any event, I'm letting the car sit turned off with the headlights on to drain the battery (not too much). I'll start her up and see if the cutout is doing its thing.
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Old 09-30-2012, 04:16 PM   #123
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Default Re: Is There An Electrician In The House?

With engine reved up & no voltage at armature terminal means that the generator AIN'T chargin' Bill W.
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Old 09-30-2012, 04:16 PM   #124
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Bill - As of yet, I have not tried another battery.

After re-installing the generator, re-attaching the wires, re-setting the belt and running the car at fast idle, the car now reads 6.3 volts everywhere except the armature side of the cutout . It reads 0 with car off or car running. The 6.3 and 0 volt reading remained steady, with the car running at fast idle, for quite a long time. This is a far cry from the 8 to 10 volts the generator was putting out since the light bulbs blew. Is 6.3 considered too low? Too high?, if so what is considered normal?
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Old 09-30-2012, 05:26 PM   #125
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Default Re: Is There An Electrician In The House?

Should be around 7 volts with the motor running fast enough for the cutout to latch. When it does, the ammeter should show charging.

The absolute highest you should ever see the voltage (at the battery) with the car running is around 7.4 volts. MAX. That's not very good for the battery, but that's what you may see on a Model a generator. Ideally, the voltage should never exceed 7.1 volts, in a perfect world.

Typical resting voltage on the battery will be between 6.7 and 6.2 volts. But it should take close to 24 hours for the battery to settle down to that voltage.
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Old 09-30-2012, 06:09 PM   #126
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Default Re: Is There An Electrician In The House?

The cut out does not have anything to do with battery voltage, it is just a switch that closes when the
generator voltage gets to around 7 volts. It just keeps battery voltage from feeding back to the generator
when the engine is not running and trying to motor the generator.

Bob
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Old 09-30-2012, 07:28 PM   #127
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Again
There should be no voltage across the cutout terminals when running.
did we check amps at the cut out terminals when running with an external amp meter
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Old 09-30-2012, 10:38 PM   #128
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0V at armature side means the gen is not genning and the cutout is open. The 6.2 you are reading is surface voltage on the battery itself. Any gen may need to be polarized from time to time. I have had to re-polarize my A gen several times over 10 yrs, usually after sitting all winter. You are not polarizing the cutout with this process, but re-magnetizing the pole shoe magnets. The cutout has no way of knowing if the battery charge is low. Usually if all systems are correctly operational you set the third brush to show about a 4 amp charge at fast idle if mostly daylight driving, higher if more nighttime driving. This is a compromise, it will never be perfect but it sure worked anyway for the past 80 yrs for most of us. I am well aware of motoring a gen to 'test' it, but the battery voltage supplied should be the same as the gen is rated for, not higher or lower. And yes, it will not motor fast because it was not made to work that way. The field coils need to be ohmed out and the armature needs to be put on a growler. These 2 tests take 5 min. Drop by my shop in N. Texas and I'll run these tests for you for free. It requires several types of tests to test a gen. I'd still put on a known good gen and known good cutout and see what happens, you have nothing to lose. You did state the battery was recently load tested but I'd try another known good battery also. The quite diverse opinions of what needs to happen here are intriguing. I do know that part of the problem is that none of us can be right there to check it all out.
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Old 09-30-2012, 10:44 PM   #129
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Been there done that and offered my services for free at my shop and I am a hell of a lot closer than Texas about 50 miles
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Old 10-01-2012, 05:29 AM   #130
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First DON'T use a digital meter for your tests. ONLY use a good analog meter.
As mentioned the stock cutout, or diode cutout is a simple OFF-ON switch (relay) that closes the contacts when about 6 volts from the generator is reached. It has no regulation and doesn't care what the battery voltage is. A good generator should be able to charge the battery as long as the engine is running about 475 RPM's or more. Even is the engine was running at 100 RPM there should be some voltage showing at the output stud, but it might only be a volt or two.

Since your generator had output, but now doesn't after the shop motored it, either he messed up something, or you may have left the insulator off the cutout for the angle bracket that is fastened to the generator output stud. Without the insulator on the cutout terminal the generator output stud will always show 0 volts, since the output would now be grounded. The thin insulator goes on the input (generator stud) side, and the thick insulator goes on the output side of the cutout. Be sure you don't use screws that are too long on the cutout terminals, or they may screw into the cutout windings and short them out.

Vince is saying that 0 volts should show ACROSS the cutout terminals. In other words the voltage drop across the cutout terminal should be 0 volts. In reality there is a very small voltage drop such as .1 volt or less with about 5 amps current flow. A cheaper repro cutout may have .2 or more volts dropped across the poor quality contacts in the cutout.
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Old 10-01-2012, 09:21 AM   #131
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Bill - The cut-out insulators are in place as you describe.

I hate to be a pest and continue to ask the same type of questions over and over again, but I still need to understand how the cut-out operates internally. I’m sure the terminology I’m using to describe my plight leaves much to be desired.

In any event, here I go again;
The cover on my cut-out contains the FORD script and is embossed “BATT” above the post where the wires that lead to the lights, junction box, etc. are attached.

The opposite post is embossed “ARM”.

I removed the cover from the cut-out and inspected the guts and found points very similar to the points in the distributor. The BATT terminal is a simple metal device that serves as the STATIONARY side of the points. This post gets its electricity from the battery via one of the wires connected to its external post. Unless you have a fuse mounted on your starter, or somewhere else in the system, with the fuse installed this post will be HOT. If you have an un-fused system, the post is always HOT.


The ARM side is also a metal plate. This plate is soldered to a fairly thick coiled copper wire. The opposite end of the coiled copper wire is soldered to the SPRUNG side of the points.

Based on the way this thing is put together it appears when the points are OPEN there is no electricity flowing from the BATT side to the ARM side. That means the battery is the source of power to the electrical system. I believe the battery sends out power in one direction (battery outward) which causes it to discharge. When the voltage from the battery drops below the output voltage produced by the generator it needs to be charged. This condition causes the cut-out to “CLOSE” the points allowing current to flow from the BATT terminal to the ARM terminal and into the generator where through some type of magic the generator takes over as the source of power to the electrical system. As the power generated by the generator is bi-directional it serves to charge the battery and provide the juice to power everything. When the battery is sufficiently charged, or the car is turned off, the points open breaking the circuit and allowing the battery to take over once again.

Now, if what I am assuming (and we all know what that means) is correct, with the car running and the points closed there should be voltage at both the BATT and ARM side of the cut-out.
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Old 10-01-2012, 10:09 AM   #132
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Your last sentence is correct but your theory of how the cut out works is wrong. The cut out does not
sense battery voltage it senses generator voltage, that is why you have to adjust the third brush so you
don't over charge the battery.

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Old 10-01-2012, 10:23 AM   #133
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Okay, I think I understand. It's the armature side of the cutout that tells the points to close. That's how the switch is accomplished between battery power and generator power.
Correct?
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Old 10-01-2012, 10:41 AM   #134
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Now you got it
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Old 10-01-2012, 10:54 AM   #135
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Bob - now that I think about it, that makes perfect sense. Okay, to put an end to my pestering about the cutout, another one of my cockamamie theories is in regard to determining if the points are opening/closing. I'm assuming (and we all know what that means) that if the car is running and the points are closed I should get some kind of voltage reading at the arm and batt side of the cutout. If not, the points are open and the armature side should show zero. I would think, with the points open, the BATT side is receiving juice from the battery connection resulting in a voltage reading. Please straighten me out on this one.
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Old 10-01-2012, 11:55 AM   #136
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Yes, you need voltage FROM the generator to close the points.

Bob
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Old 10-01-2012, 01:08 PM   #137
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I think at this point whether the cutout is opening/closing ( I will replace it with a diode cutout) probably has no bearing on the reason why I originally opened this thread. That is, the high voltage produced by the generator (as high as 10 volts) that caused my lights to go belly-up.
The mystery to me in all of this is why have the voltage readings suddenly gone from a consistent 8 volts or higher until this past Saturday when the readings dropped to a consistent 6.3 volts everywhere with car running at fast idle. So what changed between Friday’s readings and Saturday afternoons?
1. Polarized the generator
2. Removed generator, took it to a shop where it was visually inspected and motor tested. The shop is closing for vacation so that’s as far as we got.
3. Re-installed generator. Could the act of re-installing the generator resulted in an improved ground?
4. Re-installed fan belt. Free play is approximately the same as prior to removal.
5. Changed out the cut-out. Is the cutout grounded to the generator body, if so, could this ground have been improved?
6. Re-installed wires to generator cutout. Could this have resulted in a tighter/improved connection?

So now the questions become, is the reduction in voltage a result of one of the above items? If voltage consistently remains below 7 volts, is it considered normal? If so, should we declare victory, fold up the tents, and call it a day? In any event, going forward I will have the generator checked by the repair shop, and if necessary, take the car over for professional testing albeit, at this stage, I’m not sure what he will be testing for.
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Old 10-01-2012, 02:16 PM   #138
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Maybe the shop adjusted the third brush or the generator is inop

Last edited by Mitch//pa; 10-01-2012 at 02:41 PM.
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Old 10-01-2012, 02:28 PM   #139
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If you are getting 0 volts at the armature side of the cut out at fast idle you have a problem, should be
closer to 7 volts. Is your ammeter showing a charge?

Bob
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Old 10-01-2012, 03:00 PM   #140
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You should show some voltage at the generator output post anytime the generator is turning over, and when the voltage reaches 6 or more the cutout contacts should close, so the generator output will now be going to feed the battery, lights, coil and horn. If the electrical items turned on draw more than the generator is putting out in amps, then the battery will supply that portion of demand.

This is where an EVR is nice to have, so it can tell the generator to put out more when needed, so you aren't drawing down the battery.
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