VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 935-B Generator Problems

I have a 935-B Generator on a 1934 Master that I purchased and got running this spring.

The generator output seemed low and inconsistant so I pulled it apart. The brushes were almost gone so I replaced them and cleaned all the connections.

The generator now outputs about 30 amps at 1,500 rpm. After reading about other threads on this subject I am fearful that I am going to burn up the generator.

Did I screw some wireing up?
I don't remember a third brush ajustment but can the output be ajusted down on this model?

Thanks - Jeff

Thanks,

Jeff

Yes, 30 amps is way, way too high. The output should be a maximum of 12 amps. At 30 amps output you will definitely fry the generator.

The 935-B generator has a third brush adjustment. To lower the output of the generator move the third brush (the brush on top of the generator looking at the generator from the left front fender) towards the engine. Usually, the main brush (the brush closest to the left front fender) and the third brush should be around four comm. bars apart.

There is a round slotted screw on the end frame of the generator. You need to loosen that screw before moving the third brush. After you adjust the output, then tighten down the screw.

Make sure that your wiring is correct as well. The positive field wire goes to the third brush. The negative field wire goes to the insulated terminal stud on the generator, and the wire coming from the "Gen" terminal on the cut-out goes to the main brush.

The third brush was in the wrong position. I didn't realize that this generator has this system so thank you for setting me straight.

I set the generator at 20 Amps (3 comm. bars) in the 2000 RPM range. This reading is with the generator in the car and using a BluePoint inductive amp meter.

This is way above your specified max 12 amps. I did this because it gives me about 1 to 2 amps charge with my 35 Watt halogen headlights on plus dash light, tail light, etc.

I am running around 1.5 ohm resitor at the light switch that gives me about 10 amp charge rate when in the "lights off" position.

These are my questions.

1) In the "lights off" resistor position is it safe to run the generator at 10 amps charge or do I still risk burning it up even though the output is regulated?

2) If okay to question 1 how long is it safe to run in the non resistor 20 amp position? 2 minutes? 20 minutes?

If no to both then I am assuming I will need to downgrade to much lower wattage headlamps? If yes then what is the max wattage bulb that will work with this generator?

Thanks,

Jeff

You want 12 amps maximum charge...period! Charging at 20 amps will probably melt the solder in the armature....not to mention overcharging the battery as well.

If your halogen lights demand that much current get rid of them and go back to regular light bulbs. Have your headlight reflectors redone with vacuum sealed aluminum and your headlights will be as bright as sealed beams with a conventional light bulb.

I have had the reflectors redone with vacuum sealed aluminum. The brightness is amazing.

I will order some conventional headlight bulbs.

Questions.

1) How much amperage does the ingnition system consume? It looks around 5 to 8 amps???
2) With the generator set at 12 amps. Using standard headlamps, dash lights on, tail light on, car running, how much of a charge should I have left.

Thanks for the help.

Jeff

" four bars apart" : Is that including the bars under the brushes or four bars visible between the brushes?

Four bars visible between the brushes. That would be your starting point. From there you may have to adjust the third brush in either direction so that you will achieve 12 amps output.

That seems to have worked. Output is 12 amps. My starter works too. My only mistake was crossing some wires in the generator. Good thing I had it verified & tested.

This is a great post with good information.
Thanks