Voltage Regulator

Wisconsinjimmy

Wisconsinjimmy

Senior Member
I am confused as my engines generator has a regulator mounted on it and it is round, the fire wall also has a regulator on it that is rectangular with five wires two each side and one on the bottom which I think is the feed, is this factory?
 
Stock As don't have a regulator. The generator uses a third brush to control field current, so it's not really regulated per se. It depends on the load of the battery to keep the voltage in range. NEVER, NEVER run it without a battery.

Unless you have a really early A, you probably have a cylindrical generator. If it's a short can like one, it's a Powerhouse (and I don't know much about those).

The cylindrical object on top of the generator is cutout, which is essentially a relay that disconnects the battery from the generator when it's not running. Otherwise the battery would try to motor the generator against engine compression and Bad Things could happen, the least of which is running your battery down.

The rectangular box is probably the terminal box on the firewall. Right in the center, has two brass half-thumbscrews holding it in place. The two terminals are wired to the corresponding terminals on the ammeter. One side of box has 6v from the battery (via the starter) and the other terminal goes to the coil (-) terminal via a black wire, as well as the cutout terminal on the generator. Most other items (lights, horn, etc) tie into 6v via the cutout terminal on the generator.

Hope this helps. If you'd like I could scan a diagram for you.

Rgds
Ed
 
Oh, yeah: the wire on the bottom. Depending if you have a pop out ignition switch, that's probably the wire from the switch to the distributor.
 
The rectangular box is probably the terminal box on the firewall. Right in the center, has two brass half-thumbscrews holding it in place. The two terminals are wired to the corresponding terminals on the ammeter. One side of box has 6v from the battery (via the starter) and the other terminal goes to the coil (-) terminal via a black wire, as well as the cutout terminal on the generator. Most other items (lights, horn, etc) tie into 6v via the cutout terminal on the generator.

You are thinking about the junction block on the firewall this is a tin box screwed to the driver side firewall, could it be the cutout quit working and a new style regulator was installed? Thanks for the wire diagram offer but I have one.
 
Is the the box on the wall?
A14560.jpg

It is the terminal box as stated above.

And this should be the the can on the generator.

15590.jpg

Again, as stated it is the cut out. The generator will act like a motor if power is applied to it. So, to keep this from happening it "cuts out" the voltage from getting back to the generator when the generator is not running.

To help you wire things up you need a wiring diagram. Rather than put the wiring diagram image here, here is the link.

wiring diagram
 
Wisconsinjimmy said:
The rectangular box is probably the terminal box on the firewall. Right in the center, has two brass half-thumbscrews holding it in place. The two terminals are wired to the corresponding terminals on the ammeter. One side of box has 6v from the battery (via the starter) and the other terminal goes to the coil (-) terminal via a black wire, as well as the cutout terminal on the generator. Most other items (lights, horn, etc) tie into 6v via the cutout terminal on the generator.

You are thinking about the junction block on the firewall this is a tin box screwed to the driver side firewall, could it be the cutout quit working and a new style regulator was installed? Thanks for the wire diagram offer but I have one.
Click to expand...

Well, that's definitely not stock. Can you post a picture? Sounds like it might be a voltage regulator - perhaps at some point someone put on a newer style generator. Can you remove the cover and look inside? VRs look like a relay with usually three wires, armature, field, & battery (as I recall from my Hudson). Could have fourth wire for a light. Labelled A, F, B, & T.
 
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One of my spare firewalls has a rectangular METAL box mounted on it which I took to be a VR (since it has a relay and contacts inside and an adjustment screw obviously designed to change the "pull in" voltage.)

The original VRs were "electro-mechanical."

Joe K
 
The really old ones didn't have a screw - you had to bend the contacts to adjust the output.
 
Also I dunno if you could add an external regulator by removing the third brush and wiring the field to the F terminal (along with the A & B terms to their respective places). Anybody know?
 
The third brush wouldn't need to be removed, it could still be used to adjust for maximum charge rate. You would need to run the ground from the field coils inside the generator to the field terminal on the box style regulator, this would allow the generator to cycle from low to higher amps on demand. It would be easier if you used the model 46 generator that had two wires instead of a post terminal. The model 46 generator was sold as a replacement by Ford and others for the model A. The wire that would normally be grounded under the leg of the cutout would need to connect to the field terminal of the regulator.
 
The regulator was probably used with a later two brush generator, you
don't need it with your generator.
It looks like you have the wire on the wrong side of the cutout. Also do not run
the engine without having the generator hooked to the battery or you run the chance
of burning it up.
It also looks like the light switch is installed wrong.

Bob
 
The easiest way to run a voltage regulator with the model A generator is to use all original style wiring harnesses and a Fun Projects can style regulator that replaces the cutout.

Before the three different style voltage regulators that are now offered for the model A type generators were available, Some people that knew how could wire the box style regulator to work with the original generator and could be run 6 or 12 volt depending on the regulator.. most mounted the regulator on the firewall. Some hid the regulator under the seat. I suppose that this type stuff is concidered a dark art and should be avoided unless you know what you are doing. If you had a problem, you would have to know how to fix it yourself or you would probably be SOL.
 
Let me ask this, on the cut out which is mounted to the generator with two screws now standing on the driver side looking at the gen and cut out there is one screw on the front of the cut out and on the rear is a stud and nut. From my harness I have two wires bundled together with a round connecter crimped to each wire, does this go to the stud on the generator? The screw on the front of the cut out is there supposed to be a wire on this? Somehow I need power to the generator and if I come of the terminal blocks driver side and touch the stud on the generator or anywhere for that matter I get a short.
 
I'm not familiar with the two coil type regulator that is pictured. The cutout connects on one end to the post on the generator. the connection on the other end of the cutout will need a hot wire connected to it. When the generator turns fast enough to charge, the points in the cutout should close and allow power to flow back through the hot wire to the battery. I used the three coil regulator and the cutout was not used. your set up is different.
 
So I need a hot to the screw on the front of the cut out, that might be a problem as I do not see any insulator on or around that side. Back to the bench to figure out how this other regulator works, it appears the hot comes in at the bottom so I go from there.
 
There should be three wires hooked to the screw on the front of the cutout, one for the horn,
one for the light switch , and a hot one from the terminal box. You don't need that voltage regulator
on the firewall with the generator you have.

Bob
 

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Your after market regulator may have a cut out as part of it. That is why whoever did it the change bypassed the stock one on the generator. If it was me I would test the stock cut out if it works, I would return the wiring to normal by removing the old after market regulator. If the old wiring is bad you can just have a wire running from the generator cut out to the bolt on the starter switch were your battery cable connects. Very simple and would take less time than tracing out the old firewall mounted regulator. If the generator does not work, there is a very good generator / alternator repair shop on hwy 35 on the south end of Centuria WI. He also could sell you a 6 volt positive ground alternator at a good price if you wanted to go that way.
 
Bob C, Thanks for the cutaway generator pic, it helps showa LOT of stuff!

Jmeckel, You mentioned the cut out hot wire goes to the starter switch cable. REMEMBER, that wire first goes to the junction box, then makes a loop up through the ammeter, back to the other junction box terminal, THEN down to the starter switch cable. Bill W.
 
Darn hope it is not to large, but does this make sense, the screw or terminal on the front of the cutout is where the 6 volts comes in and the back terminal (stud) is where the lights and horn connect? If I use a jumper from the front terminal to the rear terminal I get nothing is this a sign of no good cutout?
Powerdrawing_zpsa704be21.png
 
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