Can a faulty cutout or would it be magneto that fried my headlight bulbs, but not my park or signals? replaced generator and added regulator and headlights work fine, no rewiring.

The cutout is not a voltage regulator. The cutout is a one-way valve, like a diode (in fact a diode can replace a mechanical cutout), which keeps current form flowing back through the generator when the generator output voltage falls below the battery voltage.

The headlamps should be powered by either the magneto - or - the battery and generator. If they can be powered by either one then something is screwed up in your wiring (such as the headlamps being wired through the ignition switch).

If you run your generator car with the battery disconnected it will blow your bulbs if you switch them on. I learned this the hard way. It will also burn out your generator but that takes a few minutes. Fortunately I realized in time what was going on. I started my '27 with the crank on mag and forgot I had not put a battery in it. Blew out the signal light bulbs and the flasher.

Sounds like the battery disconnect was off while I was running it and tried the headlights. My ignition switch is on the coil box, seperate from my light switch. Also may be why my commutator was so black, generator quit, but did not burn armature or field. My magneto cuts out after a several minute run, grounding mag coils?

Runs fine switched to battery setting

Once again a battery disconnect switch CAUSES a problem rather than preventing whatever it is supposed to prevent. If I had a dollar for every time one of those switches caused a problem, I could buy a T with the money. I get a lot of email from folks with electrical problems and I have had MANY occasions when those things caused trouble.

In fact, on the recent Grand Rapids MTFCI tour, a friend of mine from our local chapter lost all power and was temporarilly stopped by the side of the road because his battery disconnect had vibrated just loose enough to kill power to his ignition (he was running on BAT, no generator). I'm with John on this one.

Open the circuit between your battery and generator past the lights and all the generator current produced will go through the lights and raise the voltage level to 15 or 20 volts minimum and burn out the lights.

One loose connection is all you need to blow the lights and not the horn. The ammeter terminal is often the problem area.

James
.....and in about five miles of driving the generator will be "well done" and no longer working.
Ron the Coilman

Just would like to point out that if you are running one of our Voltage Regulators that look like a cutout this HIGH VOLTAGE situation CANNOT happen so long a the generator nut and voltage regulator mounting screws are installed properly. ALL Fun Projects Voltage regulators have a built in SAFETY OVERIDE which will immediately shut down the generator when the battery voltage goes "out of bounds" too high. This circuit acts rather quickly and will over ride the normal regulator circuit. It is SELF RESETTING when the problem is fixed (battery reconnected). If the generator will NOT shut down and is the source of the problem (rather than a disconnected battery), the voltage regulator will give up its life and FAIL SAFE with a permanent ground short being placed on the generator post. Having failed this way - the regulator CAN be repaired for a small fee and it is presumed the generator will be fixed before that voltage regulator is returned to service. NEVER TOSS AWAY your voltage regulator - we can almost ALWAYS fix it and we don't ask embarrassing questions like "just how did it come to be floating in the parts cleaning tank?..." We have only had 1 regulator that could not be repaired and that customer took a hack saw to it before sending it to us.

Voltage Regulator for Model T web page

John, how do you set the generator brushes to this regulator, seems the voltage stays consistant. set brushes were they would'nt arc.

Mark,
Remove the generator cover and on the third brush is a small nut. Loosen it just enough to the brush ring toward the engine or away from it.
It's been a while since I've done it, but it seems toward the engine increases the amps and away from the engine decreases them.
Do the job with the engine running just enough to generate juice and watch the ampmeter, or have an assistant.
I set the generator at 10 amps and when you test it turn on the lights and the ampmeter should show zero (or an amp or two) with the lights on.
Hope this helps you.

Joe R.

P.S.
The generator sets the same with John's regulator as it would be with the old style cutout.
I used, and still have, two of his regulators that performed well. However, the generators were where I had problems.

Joe R.

Mark:

You can download the instruction sheet for any of our regulators. Just go to Funprojects.com site and look in the technical library for the instruction sheet you need.

ONE EASY way to remember which way to rotate the third brush ring is this - THE GENERATOR IS ALWAYS trying to commit suicide. If the third brush plate comes loose, the plate will turn in the direction that the generator is already spinning and THAT will give you MORE CURRENT. Thus if the plate comes loose the generator will self advance to its maximum current output - UNGOOD!!

FYI - ALL adjustable third brush type generators for ANY MAKE or MODEL OF CAR will self advance and you will get MORE current out of any of these generators when you rotate the third brush in the same direction that the generator normally spins.