Allis C Charging problems

Jim in NC

Well-known Member
A few weeks ago, the tractor stopped charging due to the voltage regulator contacts not closing. I closed the gap and it worked for awhile, but I ended up having to replace the voltage regulator.

My C is 6v positive ground and has coil ignition. Now with the new voltage regulator, it discharges, buries the ampmeter to the left, and does return near 0 at full throttle, but still discharges. I am using clip leads for initial connections and the clips heat up quickly. The contacts spark brightly. I have replaced several regulators in my time, but have never experienced this. I have also used a second generator to troubleshoot the first one, and the results are the same.

Any help would be greatly appreciated. What am I missing?
 
Discharge sounds like cut out contacts in the regulator are stuck together. When generator output goes above battery voltage the cut out should close and charge the battery. When generator output drops below battery voltage the cut out should open and prevent battery from discharging through the generator.

Clip leads could be heating up due to poor connection causing excessive resistance. This could cause reduced generator output and be the cause of it still discharging with engine revved up.

Cause of stuck contacts with new regulator could be that the battery was inadvertently installed and engine run with reveresed polarity to the way generator was polarized
 
Clip leads were used to allow for quick disconnection since when the wires were fast connected, too much heat built up. Clearly there is a short or reverse polarity somewhere. The battery has been in place for about 3 years and one cable was replaced early in the spring. This was happening with the old regulator and the heat burnt a set of contacts. I have used a second generator with the same results. The only other change was the new regulator. Thanks for the come back.
 
most 6 volt systems have a cutout, not a regulator. If you do have a regulator, it should be connected as follows. F on generator to F on regulator- that is the ground.. regulator must be grounded with mounting bolts..The A terminal on gen to the G terminal on regulator.. last terminal is B for battery. It can be negative or positive ground depending on your tractor.

<a href="http://s436.photobucket.com/albums/qq86/steve-ill/?action=view&current=gen-regulator.jpg" target="_blank">
gen-regulator.jpg" border="0" alt="generator with regulator
</a>
 
Thanks for the diagram. I have a similar one, and have checked and checked again, but I will retrace the connections the next time I tackle it. I do not have a cutout in this system. I have seen some wiring diagrams that show resistors in the switch box, but I have no resistor on my tractor. Prior to the old regulator failing, the tractor was charging fine.
 
No resistor on your tractor is correct.

The generator regulates via a resistor in series with the field coils. With a cutout, that resistor is incorporated into the light switch. With the resistor in circuit, generator output is limited, on high charge the switch bypasses or shorts out the resistor and the generator goes full charge. This is controlled with a manual switch.

With a regulator the resistor is in the regulator and is controlled automatically.

Many 6 volt systems converted to 12 volts also use a different resistor to drop the 12 volts down to 6 volts at the coil to prevent damage to the coil. You would not have that with a 6 volt system.
 
I have changed about a half dozen tractors from 6 to 12 v systems. I know about the resistor to reduce voltage at the coil and distributor used when converting to 12 volts. I did not think that a generator system required one, but just wanted to mention it. We had a 3 inch rain last night and after some cleaning up, I hope to get to the C later in the day.
 
Iv heard something about those old regulators (purely word of mouth, I know nothing about them) but iv heard that there is some way that it gets magnitized? An you have to reverse the wires to de-magnitize them. Like i said i dont know anything about them, just passing that bit of information along that i was told.
 
Steve, My tractor is wired just as your diagram shows. My new regulator which is the same kind as the old one has a Load terminal on it, but it is not used. I am beginnong to wonder if the new regulator is bad, too.
 
it would be best to use a 6 volt regulator without the L terminal. THe L is "light" or "load" which gave power to the light switch when key was on. ( i think) remember the "B" terminal is always hot... after a few years, the newer regulators had the L eliminated and combined function into the B.. YOU could put power to the L terminal and see if that helps, but i think the power acutally came out of the L terminal, not go into the regulator....still sounds like you have a short somewhere.
 

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