Where should the Ammeter needle be?

[Jeremy58Cub]

After having to charge the battery too often, I finally took the generator and voltage regulator off the Cub and took them to an auto electric shop.

Results: Generator, great shape, putting out 8 volts or so. Regulator, bad. Not doing anything.

They sold me a new regulator, I walk out the door and get home and put it on. The needle on the ammeter jumps over to the charging side for the first time since who knows when!

After a few hours running it, over a couple days, the needle starts staying back on the discharge side.

Bad regulator right? I took it back down to them and they tested it and said, no problem. Must be defective. Here's another one.

I get home, put it in and again, ammeter on the charging side.

Again, a few hours of running over a week or so, and I am out plowing today. 12" or so up here, and I notice half way through, that the needle is on the discharge side. Not by much, but definately below the 0. If I turn the lights on, it dips way below. Not good right?

After all that, if you are still reading, my question is this:

Should the ammeter needle ever drop below the 0?

Follow up question would be, since the chances of 2 voltage regulators being bad is low, what could be the cause of the voltage regulators working, then not working? Then again, maybe it could be 2 bad ones in a row.

Any suggestions are appreciated!

~Jeremy

[rocketman]

Any chance the wire to the meter is missing insulation or the wire itself is corroded or weak? Are connections clean? Maybe after it "heats up" it creates enough resistance to create a false reading at the gauge.

[Bigdog]

Jeremy, the ammeter will dip below zero when the current being used exceeds what the generator is putting out. This can happen when the tractor is idling and the lights are on. Increasing engine rpms thus increasing generator output generally corrects this.
The odds of 2 bad regulators is sadly better than we think. Since the generator tested OK and the regulator came up bad twice we would assume that the generator is OK. But that is not always the case
Make sure they are giving you the right regulator. I'm guessing you're running a standard 6 volt positive ground system. Re-check all of your connections and make sure you have connected it correctly. When the system was charging how high was the needle reading?

[Jeremy58Cub]

At it's best, it was a needles width short of the first line on the charge side.

I thought it could have been connections too, so I cleaned them all off. Took the panel off and cleaned behind there, removed the gauge, cleaned all the connections really well.

The wires are probably original, but look to be in pretty good shape. A new wire harness is probably in the future, but I don't think it is a NEED right now, more a WANT!



Rocketman, I was wondering that myself, if it could be the gauge. I am not sure. I guess I will know better the next time I go to start it up. The last 45 minutes or so it was showing on the discharge side.

Bigdog, I am running 6V Pos ground.

The regulator says on the cover, 6 volt pos ground.

When I increase RPM's the needle does try to come back to the charge side, it just doesn't make it all the way, and if the lights are on full and rear, it drops almost all the way to the 2nd line.

[George Willer]

This may not be it, but a loose belt is a possibility. Do you have it tensioned properly?

[rocketman]

Really, really dumb question.... You do have a 6 volt ammeter correct? I know when I replaced mine, the IH dealer was sure to give me a 6 volt one. IF you had a 12 volt ammeter, it would explain the problem (at least I think so).

I believe BD gave a great answer though. I should have said that.

[Donny M]

When you replaced the first bad regulator how long did the generator charge A few days from what I read. Could be that the 3rd brush on the generator has moved. Just a thought.

[George Willer]

Really, really dumb question.... You do have a 6 volt ammeter correct? I know when I replaced mine, the IH dealer was sure to give me a 6 volt one. IF you had a 12 volt ammeter, it would explain the problem (at least I think so).

I believe BD gave a great answer though. I should have said that.

The ammeter reads AMPS! It doesn't care or even know about volts.

[splicer]

I had the same problem with mine. turned out to be a bad Generator. When you were explaining your problem, sounded just like my problem. Gauge going to one side then the other, then turn on the lights and watch it really discharge. I found a place (and posted it on this board somewhere) where they sold me EVERY part you can possibly put on the generator, and I did. seems like when I dismantled the gen, the rear brass bushing was worn enough that when it warmed up, the rotor came in contact slightly with the windings and created the discharge(after it ran for awhile). if you check the easy things first (of course) take the rear off the gen, slide the rotor out and have a look.

[JohnL (BlackJeep)]

Mine usually stays on the positive side, but jumps around violently. Is this normal behavior?

BlackJeep

[Bigdog]

some movement is normal but it should not be violent

[Jim Becker]

I don't see anythere in this wher you said the battery started to go dead. I am not sure you have a problem.

Do this before you do anything else: With the engine off, take the ground cable off the battery. Then look closely at the ammeter and see where the needle is. THAT is zero, doesn't matter what the numbers on the face say. Does that change your discharge story? Then measure the voltage when the engine running after the charge rate drops off. If it is more than the battery shows with the engine off, everything is normal.

[awander]

There is no such thing as a 6V or 12V ammeter. s George(I think) said, the ammeter reads current, and there will be almost ZERO volts across it. If there is more than that, then the ammeter is open. The IH counter man probably sold you "the ammeter that was stock for a 6V system", but that just means that it is the part they used at that time. Probably a different faceplate and markings, but still not voltage dependent.

If you want to confirm ammeter operation, switch the wires on the back of the ammeter. If the needle now goes positive instead of negattive, then the ammeter is probably ok. If it still reads negative, get a new ammeter.

[Jim Becker]

The original ammeters on the 6 volt systems were mostly (all?) 20 amp meters. If you convert to a high output alternator (6 or 12 volts) it will probably be capable of blowing way past 20 amps. You need an ammeter that can handle anything the alternator wil produce or change it out for a voltmeter.

[John *.?-!.* cub owner]

Well folks, there is a difference in the modern 12 volt ammeters used for cars and in the older 6 or 12 volt ones. The new 12 volt ones sold by many autoparts stores have an elctronic circuit in them for measuring amps rather than the traditional shunt and voltmeter. If your dealer stocks this type for use on tractors also, he was correct in what he said.