How do I check my voltage regulator

chappie

Member
I have an Allis D17. Because of the ice on my roadway, I have to drive this tractor at least once daily, about a half mile, to get to my truck. I also use it with it's blade to clear snow when needed. So, this time of year it dont get used real much, but gets used almost daily.

The battery is fairly new, and was tested to be good. The starter was just replaced with a brand new one.

What's happening, is that I have to charge the battery about once every 10 days. When I first charge it, the tractor starts fairly quick. But after several days it starts slower, and eventually it wont start until I charge the battery. (Usually after 7 to 10 days).

The ammeter does not show anything. (But I am not sure it it's working).

I should mention that I changed the polarity to a NEG ground last summer, and polarized the generator. I reversed the wires on the coil, but not on the ammeter.

It seems odd that it will start and run for that many days, then gradually wear down the battery. (The tractor dont have lights). This tells me that there must be some charge coming from the genny, but not enough.

I know the generator works, because when I polarized it, it tried to turn like a motor.

Am I correct to assume that a genny is either good or bad, and there is no "gray area". Meaning that as long as it "motors", it's puting out enough charge?

Assuming I am correct about the genny, that indicates that the voltage regulator must be weak. Meaning that it must be charging some, but not enough.

That's where I get lost. How do I test the regulator to see if it's charging and how much charge it's putting out?

-OR- Is it better to just replace it?

I should mention that I'd prefer to not spend a lot on this, because as soon as the weather warms up, I plan to replace the genny with an alternator. But since I have to rely on this tractor to get me to my truck in bad weather, I need to make sure it keeps running. I suppose I could just charge the battery twice a week, to be sure it starts, but I should not have to do that if the charging system is working properly.

Thanks for all help.
 
It sounds like your amp meter isn't working and you would have to reverse the wires on it or it would read backwards. And the voltage regulator probably isn't working or you have a wiring problem. And yeah you can run quite a while on just a battery.
 
Did you change the regulator?
Some regulators will work only with positive ground.
Mine is that way. It says "pos" near the mount bolt
 
"Some regulators will work only with positive ground."

In the case of the mechanical VR's we are working with here, in fact they will "work" on either polarity as there's nothing solid state nor any permanent magents in them, the reason for polarity designation is that different metals are used in the upper and lower contacts and contact life will be shortened if they are used at the opposite polarity of their specific design.

Check it out on pages 10 and 11 in the Delco .pdf manual linked below.
Delco
 
Had the same problem with dads D-17 last week. If you do a search on this site John T has a real good set of instructions. Mine was a bad generator. will take you about 20 to go through it all .
 
This is an original mechanical V.R. I was not aware of the different metals being used on the contacts, for reversed polarity. (I downloaded that Delco PDF file and read about it).
I suppose I could put it back to POS ground by just swapping the battery cables and polarizing it again. (and reversing the coil wires again too). But I may or may not do this, since I wont be using the generator much longer. As soon as the weather warms up, I'm changing to an Alternator. That MUST be a NEG ground.

I can see why everything was changed to alternators, because generators are a pain in the butt.

I did confirm that the Ammeter works. I connected a headlight bulb to the headlight switch, and the Ammeter did move (Backwards, because of it still being wired for POS ground).

So, I know that Ammeter works, but it's still not charging.
I checked all the wiring, and everything is connected, and looks good.
I loosened all the screws on the V.R. and retightened them to make sure the was contact. I also clipped on a wire to make sure the V.R. was grounded. STILL NO CHARGE.

So, I guess I either just keep charging the battery till weather allows me to change to an alternator, or see if I can find a working used V.R. and see if that fixes it.

NOTE: My V.R. has FOUR wires on it. Three on the left, one on the right. (bottom view).

So, finding a used FOUR wire one is not likely, since most of them seem to have three wires.

Thanks to everyone who replied.
 
"I'm changing to an Alternator. That MUST be a NEG ground."

NOPE, there's all sorts of (+) ground alternators out there if you would choose to go that route.
 

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