Farmall H charging question

I have an H 6 volt, positive ground that I can't get to charge. New battery, new regulator, new ammeter, new wires and a 3 brush generator that just came out of the shop. All the connections are clean, the regulator mount is properly grounded, polorized the regulator but still no charge.

I was just talking to my friend and he asked me where I got the generator and I really am not sure.
He thinks maybe the generator is ment for mounting on the other side of an engine and thus it is turning the wrong way. My friend just called me and said according to what he read that when you polarize the regulator, that would take care of the rotation issue with the generator. With the tractor running and the wires disconected from the generator, I should be able to get a reading from the A terminal correct? Do I even need a voltage regulator with the 3 brush generator?

Even if the generator was from a tractor or engine where it was mounted on the left, rather than the right side as your H, it would rotate the same way. If it was set up to be rotated end for end, 180 degrees, then it would rotate the opposite way but these applications are pretty rare. Your generator shop can confirm this, but most likely rotation direction is not your problem. I finally took tractor, generator mounted, wiring, etc. to the generator shop to have it checked out under real world conditions.

Changing from one side of the engine to the other won't change the way it turns. it would have to be mounted end for end.

Some of those had a small arrow. Look and see if it is grabbing air with the fins.

This will get the job done. Jim
John Ts grand procedure for checking charging system

1. Ground the F (field) on generator. If that makes it charge the regulator side of voltage regulator is bad

2. If still does not charge, leave ground on F and jumper A (armature) post on generator to BAT output on regulator. Be careful not to arc spark the threads on armature post. If that makes it charge then the cut out section of regulator is bad.

If it still does not charge, you have bypassed the regulator and have a generator or wiring problem.

A defective right out of the box new regulator seems be getting quite common.

You actually polarize the generator. Instructions that come with regulator usually suggest to polarize by momentarily shorting from regulator armature to Bat post. This is just a convenient way to touch hot battery voltage to the armature post, sending current through the field coils and polarizing the iron core pieces of the field coils of the generator.

(quoted from post at 21:21:07 06/02/14) Some of those had a small arrow. Look and see if it is grabbing air with the fins.

Click to expand...

No fan on an H generator. They are completely enclosed, no air circulation through the generator. They are only designed for low output so they are not dependent on ventilation for cooling.

I am thinking maybe the 3rd brush is part of my problem.
I have installed two new voltage regulators, thinking I had a bad one. Also two new ammeters.
Grounded the voltage regulator with a wire from the regulator mounting bolt to a frame grd.

I have two other H's, so maybe I will try changing the generator on this one with one of the others that do charge.

The third brush provides the electrical power to the field coils. The electrical circuit goes from the F terminal, through the field coils, the third brush (insulated), the armature commutator and windings, and then though the grounding brush to the generator case. The circuit for the A terminal is through the insulated brush (opposite the grounding brush) though the armature commutator and windings, and then though the grounding brush to the generator case.

With the F terminal disconnected on the generator and the engine running you should have somewhere from about 1/2 volt up to 3 or 4 volts depending on engine speed. The voltage on the A terminal will be a bit more than that. If you short the F terminal to the generator case the voltage at the A terminal should rise and close the cutout relay in the regulator at which time the voltage will be limited to battery voltage.

DO NOT SHORT THE F TERMINAL TO THE CASE UNLESS THE A TERMINAL IS CONNECTED TO THE REGULATOR AND BATTERY.

If you short the F terminal without the A terminal being somehow connected to a battery the voltage can go high enough to arc through the insulation and ruin the armature.

Two new regs did you get the correctone for the gen the tag on the genny will tell you which reg you need and the wire from the field going to the lite sw will ot be used where did yu get the reg cause if you dont have the correct one that will be a problem.

The tag on the Genny is missing. I just bought a 6 volt positive ground regulator.

"My friend just called me and said according to what he read that when you polarize the regulator"


YOUR FRIEND IS WRONG AS RAIN While a Generator indeed needs to be correctly Polarized, a Voltage Regulator DOES NOT.

NOTE If a Generator was polarized at the shop or factory at (say Neg Ground) a polarity opposite from your tractor (Positive Ground) and you failed to correctly polarize it before start up
YOU CAN DAMAGE THE VOLTAGE REGULATOR

TRY TO CORRECTLY POLARIZE THE GENERATOR BEFORE YOU START IT AGAIN

"With the tractor running and the wires disconected from the generator, I should be able to get a reading from the A terminal correct"?

YES A Generators output is between its ARM post and its case ground. The open circuit unloaded voltage would depend on the RPM and how much residual magnetism is in the field poles


"Do I even need a voltage regulator with the 3 brush generator?"

YES The Voltage Regulator allows for the correct charge plus prevents overcharging.

I would Polarize the Generator then try again and hopefully the VR wasn't damaged if the Gennys was polarized for Neg ground while the tractor is Pos ground !!!!!!!!!

Jim was kind enough to already post a link to my Troubleshooting Procedure down below (also posted here) so Polarize the generator and run through its tests will help determine the cause of non charging PROVIDED ALL IS WIRED CORRECT???

John T
Another link to my Troubleshooting Procedure

"I have installed two new voltage regulators, thinking I had a bad one"

IF THE GENERATOR IS POLARIZED OPPOSITE FROM TRACTOR BATETRY POLARITY, YOU CAN TRASH A VOLTAGE REGULATOR

At a shop or factory its quite possible a Genny is Polarized for Negative Ground and if your tractor is still its original Pos Ground THAT CAN TRASH A VOLTAGE REGULATOR

See my post above for more

John T

Just some more info. This tractor was orginaly a coil ignition. I installed a magneto. It has a 3 position light switch, that I have bypassed.

I repolarized the genny. I then tried it and no charge. I removed the field wire at the genny and tested from the field post to the genny case. (engine running) It tested at 0.20 volts. I tested the A post the same way and it read 0.20 volts
I have power on both ammeter terminals. I also have power at the Bat terminal on the reg.

So for now back out to the shed and do more testing.

"He thinks maybe the generator is ment for mounting on the other side of an engine and thus it is turning the wrong way."

I really have to bite my tongue sometimes. :>)

Allan

John I followed your trouble shooting procedure.

When I got to the part about jumping the Vr's Arm and Bat terminals it showed charge on the ammeter, not alot but some. I guess I will try another VR. This one is new, so it must have been bad right out of the box.

Thanks

Yea, I Know. It isn't Rocket Science, but sometimes I can make things seem that way. LOL!

It ticks me off when new out of the box stuff does not work and no returns on electrical items.

Between the VR"s ARM and BAT terminal is basically a normally open Cutout Relay. Once the genny is running and the ARM voltage is higher then BAT, that relay closes so the gennys output can get to and charge the battery. If it charges well with that jump but not otherwise, the VR may be bad orrrrrrrrrrr the genny isn"t producing enough voltage to latch the relay closed (may still show a small charge in by pass mode). If you dead ground the gennys FLD post that puts genny in full max charge condition so try that first n see if the relay pulls in and she charges???? If so then but NOT otherwise, the genny is okay so the VR must be the problem. Also, the VR needs that same good ground for that to work also INSURE A GOOD VR GROUND.

The VR needs a good ground to work as far as the Field control portion also, be sure it ahs one or try a grounding jumper to it

John T

Youve got a mag, and a new battery, so maybe it just doesnt need to charge, so youre not getting a reading from the amp gauge because there is no need for it to charge? These type of problems are why I switch to alternators.