Farmall Cub

i'm doing a 12v conversion and i was wondering if i could just put a 12v voltage reg on my old original 6v generator and make it produce 12v??? it is the kind with 3 fixed brushes delco remy number 1100531 8M 9.

I've never tried this. But, from an electrical perspective, I would have a hard time imagining this working.

A regulator trims down a ragged looking voltage to something slightly lower - but more stable. The trimmed excess is dissipated in heat (wasted energy). The more excess generated - the more heat generated (and energy wasted).

I would expect that if a generator were putting out 12 volts before it hit the regulator, that would leave a lot of excess heat to dissipate. It wouldn't seem logical to design something with the knowledge that 50% of its energy would be burned off rather than put to work. Therefore, I would expect the designers of the generators to have made them to output only a little over six volts.

I would imagine that a 12 volt regulator would simply sit idly waiting for something in excess of 12 volts to burn off. In essence, you would just get unfiltered generator output of a little more than 6 volts.

Again, I have never put a meter on the generator's output. This is just from other experience.

JMHO, I would sell the working 6v generator and regulator to help finance a one wire alternator and forget about the old separate regulator. BTW, (6v) if it ain't broke, don't fix it).

kirkcudbright wrote:I've never tried this. But, from an electrical perspective, I would have a hard time imagining this working.

A regulator trims down a ragged looking voltage to something slightly lower - but more stable. The trimmed excess is dissipated in heat (wasted energy). The more excess generated - the more heat generated (and energy wasted).

I would expect that if a generator were putting out 12 volts before it hit the regulator, that would leave a lot of excess heat to dissipate. It wouldn't seem logical to design something with the knowledge that 50% of its energy would be burned off rather than put to work. Therefore, I would expect the designers of the generators to have made them to output only a little over six volts.

I would imagine that a 12 volt regulator would simply sit idly waiting for something in excess of 12 volts to burn off. In essence, you would just get unfiltered generator output of a little more than 6 volts.

Again, I have never put a meter on the generator's output. This is just from other experience.

Not to be contrary but I don’t think that’s how it works this voltage regulator works. It is my understanding that in a motorcycle or lawnmower you have permanent magnets around the flywheel and a stator in the middle (stationary). The permanent magnets have a given field strength. As the engine goes up and down in speed the voltage and frequency speed up and slow down accordingly. This is fed into a shunt type voltage regulator that has fins on it and is solid state. It gets hot as it uses a configuration of diodes to turn the ac into a stepped dc output and shunt excess voltage to ground to maintain the 12v set point.

On an older style generator you have a voltage regulator that takes a sample of produced voltage and compares that to a preset value. It will then apply a varying amount of current to the stationary field windings in the stator. This magnetic field will induce a voltage in the spinning rotor. The voltage regulator will raise and lower field voltage to maintain a constant out put as load and rpms change. We get dc because this is a generator not an alternator and has a comutator instead of slip rings. A comutator allows us to only take the generated voltage off 1 side for each polarity. Because all the current being generated has to go through the brushes generators are larger heavier and produce lower power compared to an alternator. Especially at low rpms. But they produce a pure straight line DC. This is better for charging batteries than a stepped dc output.

So the real question is if field windings are large enough to produce a powerful enough magnetic field to produce 12v then my idea is going to work. Since everything else I have encoutered on a cub is engineerd to perfection I am wondering if the field windings are engineered to produce around 7v in a “full field” condition. I will find out tomorrow. Because I am going to put a 12v regulator on and try it.

This cub has been sitting for a long time. I have a 12v battery, 12v headlights, and 12v coil, and old 12v voltage regulator laying here so it makes more sense to just put them on than to spend $$$$ buying all that stuff that it need any way. Sorry if I seem snooty I don’t mean to be…..

check this link out if you want to learn more about how generators work. neat stuff, i didn't know there were so many different kinds!
http://www.venselenterprises.com/techti ... rators.pdf

Let us know how this works. I've known of others who have done this, in the past, with satisfactory results. Others, it has not worked as well for. Several years ago, I put a 12v. battery on my 48, cutout equipped Cub and was surprised to find the generator charging the battery at about 14v. I didn't leave it that way, however.

I have not tried it. If installing a 12 volt regulator, a 12 volt battery is also necessary. Polarizing the generator is necessary before starting the tractor. Obviously the 6 volt generator will not produce 12 volts except at higher speeds. So charging, if it occurs, will only be at higher speeds and will be a lower amperes than when at 6 volts. Volts and amperes both increase at higher speeds.
So it might work, some have reported that it does. But it probably will not work exceptionally well, all things considered. If you try it, please post the results and add to our collective knowledge.

the 6 volt generator can put out 12 volts "But" the field windings will burn up in a short time.. also will only produce 12 volt at high RPM.If you want 12 volt then the way to go is with a one wire alternator.

I don't know about the output on the 6v Cub generator, but my JD A 12v puts out in excess of 28v when full fielded.

the faster any generator spins the more voltage it will put out. It will soon burn out. especially fully fielded.

I got a little time to work on the cub before work today, made a new wiring harness up and put it on. I then put an old 12v reg off of my spare TD6 dozer, not exactly a match made in heaven because the generator on the dozer is like the size of a stick of fire wood but the cub genny can defiantly make 12v. Now I need to see if I can adjust the regulator. I am wondering if reg is stuck full fielding the generator. Here are the results.

Shut down Battery voltage: 13.5
Idling with battery connected 14.5
Full rpm with battery connected 18V
Idling with battery disconnected: 10.4
Full rpm with battery disconnected: 14.4

18v will burn out your coil right quick.

I would never deliberately disconnect the battery on any vehicle while the engine is running. No good can come from that.

here is some great info if anyone wants to learn more about the V.R. looks like that big rectangle one i have on there now off the TD6 is ment for a different kind of generator and is not interchangable.
http://www.stinsonclub.org/PublicTech/Y ... (regulator).pdf

your regulator should be grounded to the tractor. I would be interested to hear how long the 6 Volt generator last! In my experionce not long.!!