H Charging system

Question for Bob M,(Farmallbob) or others. I posted back on Oct. 4th about this & still can't seem to get this thing to show charging,as before, the guy that did the Gen. & installed the new V.R. had polarized at his shop,if that's possible, told him it was positive ground. I have the 4 position switch like in diagram #3, but you said to use diagram #2, witch I have done,attached headlights wire to the top post where the dimming resistor is, & the rear light to the terminal on the #3 diagram, although mine has 2 screw terminals that are conected here. Now the only thing that I see different on mine from either #2 or#3 diagram is, the wires on the coil are opposite. Don't believe this could be my problem or could it ? Also, if I change it to the correct way, I have to change the connections on the switch too, or that will be backwards too ?(in for on, out for off)? I have power at both terminal on the Amp. gauge, & shows discharge when switch is pulled on or lights or on, so know that gauge works. Do I need to polarize again ? Also, I want to hook up a Hour Meter, to the coil, but which terminal to which ? The hour meter has both a pos. & neg terminals ? God do I love this electrical stuff, keeps me off the streets ! As always, Thanks guys for any & all guidance, AL

The full field process in this outline of checks will determine the status of the system. Polarization is important. Doing it is simple and requires a piece of 10 gauge solid house wire to jump from the ARM terminal to the BAT terminal on the regulator. Tractor not running, all things connected. Touch the jump for one second. The coil should be connected such that the wire going to the distributor is connected to the Positive terminal if positive ground. No wires should connect from a field terminal to the 4 position switch. Good luck. Jim
John T charging

hey jim, a couple years back i had a problem with my h charging, everything tested good on the bench, but when installed on the tractor, the genny would not charge, even grounding the f terminal. if i remember you walked me thru isolating the brushes on the genny with some cardboard strips, and checking for continuity. it turned out the insulation on one of the bolts thru the case of the genny would short out when you tightened the nut up. i tried to find the post , but had no success. do you remember what the test proceedure was??

I don't know if you painted this tractor or not, but when I did mine I painted the switch box separate and after putting it all together I was not getting a ground from the switch to the box and frame. So no charge on the meter. Had to remove the box and get some bare metal for the switch to ground.

Randy

Sure.
The two types of Delco generator encountered on a Farmall have either three brushes, or two brushes.
Both systems use an external ground to allow current to flow through the field windings. Thus there are connections inside that provide the Hot side for that current. The three brush gets its field source from the third brush, picking up voltage from the commutator next to the primary ARM connected brush. The closer it is to the ARM brush, the more voltage is available to be used by the field then out the F terminal to ground (in those it is directly grounded if the 4 way switch is set to H D or B and through a resistor if on L.)
To check for internal shorts to ground, the 3rd brush must be isolated from the commutator. Lifting the brush, and putting a plastic knife, or piece of butter tub top, under it accomplishes this well. now, if the field wire is not on the F terminal, the entire field winding set is insulated from ground. If it is found to be not insulated the fault is either the brush holder, or a wire in the windings or attachments touching the frame, or iron cores of the field. Infinite resistance when checked with an ohm meter between the case and the F terminal is a good thing. Near zero to 2 ohms will be measured between the Isolated brush, and the F terminal.
If a two brush is tested, the field is attached to the ARM brush directly, thus as it gets volts from charging, it is directly energized. To isolate the field it is also necessary to isolate the ARM brush Thus the Arm brush is lifted and an insulating shim is inserted as above. The Bat post must also be disconnected from the regulator because there are windings in the regulators cutout relay that will be connected, and not to be included in the field circuit analysis. The F terminal is also disconnected as above. Again the result is an isolated field. The Ohms from case to F terminal must be infinite. the ohms from the Arm terminal (this time) to the F terminal should be near Zero or 2 ohms.
To isolate the Armature from ground, it is necessary to raise the ground brush (only) and insulate that as above. With all terminals disconnected, the ohms between the Arm terminal and the Case should be infinite. The measurement from the Arm terminal to the Commutator bars under the lifted brush will be Zero or less than .5 ohms. The Armature has heavy windings and little resistance. The isolated brush is grounded and should have zero ohms between it and the case. I hope this is the discussion you asked for! Jim

yup jim, thats the one!!! that dang genny drove me nutz trying to get that h to charge. had it back to the rebuilder a couple times, it would bench test great, regulator worked great, wiring harness was correct, but as soon as everything was hooked up to the tractor .....no charge. thats when you walked me thru testing the genny installed on the tractor and found the short where the either the arm or field bolt was shorting on the case because the insulator had cracked on the inside of the genny case, when the wire was attached and tightened down, it would short and cause no charge condition. thanks...glenn