Model H charging system

Stumpy · Mar 8, 2009

Good afternoon,

I have a "44 H with a cutout still on the generator and the low/ high control on the light switch. The tractor is new to me, and I am new to Farmalls. My question is does the light switch provide current to the field terminal on the generator? Reason I ask is there is no indication of voltage at the field or arm termials. If I manually close the cutout I get voltage right through the generator and out the field terminal.

Would I power the field to test the generator?

Thanks for your help.

Stumpy

Anonymous-0 · Mar 8, 2009

No domt put batt volts on the field. Do you have batt volts on the bat terminal of the cut-out Thats the first place to check. Then you can polarize the gen by touching a wire from the batt terminal to the ARM post on the gen. Make sure you dont touch the field. Then start the tracroe if it doesent chow charge then ground the field that shlould make it charge. There are more things to check but do these first.

Stumpy · Mar 8, 2009

OK, I polarized, got a spark, still no charge. I showed voltage @ batt terminal of cutout, nothing @ arm terminal. I grounded field against the gen case. No go. I did removed the band from the gen case and found that the third brush was loose, tightened it up. I checked for voltage @ arm terminal and got about one volt. for the heck of it I closed the cutout manually and bang! Away it went. I can now get the cutout to open and close by itself, just a bit sluggishly. It will charge on high, but not on low. At least I know the generator is working now.

Can it be that the generator had lost its magnetism? THis tractor was hauled out of the weeds by a friend about three weeks ago and judging by the green/ rust it has sat for a looong time. I replaced all the original cloth covered wiring that was bare in many spots along with making up new 1/0 cables with true crimped on ends. New six volt battery/ tractor runs like a million bucks now that all the usual things have been adressed like carb/ plugs/ points/etc.

The charging system working is icing on the cake! THanks

Stumpy

CNKS · Mar 8, 2009

Not sure this will work for a cutout, but it identified my bad VR.
Bob Ms diagrams

Janicholson · Mar 8, 2009

The light switch grounds the field terminal through a resistor on the light sw in the L position. This resistor can go bad. It is about 1.5 ohms or there about. It needs at least a 50 watt resistor (wire wound, or ceramic) it will get hot, so keep things away from it. JimN

John T · Mar 8, 2009

The light switch provides the gennys Field post EITHER a dead short to frame ground for High Charge or a resistive ground for Low Charge. The light switch needs a good frame ground connection to work..

The gennys output is between the gennys case ground and its ARM post

Voltage and the resultant current to create an electromagnetic field from the gennys Field windings is applied between the gennys ARM post and frame ground via the gennys FLD post to the light switch

Use my Troubleshooting Procedure for a Cutout Relay system to determine the cause of non charging

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=304795external ground supplied by the

John T
John Ts Troubleshooting Procedure

Anonymous-0 · Mar 9, 2009

You gen probably has the third brush adjustable. There is a slotted screw on the end of the gen above the shaft toward the top of the end plate. Loosen that one up then you can rotate the third brush move it closer to get more charge. You dont measure the volts on the field measure on the A terminal when its running. Glad it worked for you. If you know how to use an OHM meter check to make sure the control has ground to the battery also the base of the cut-out has ground and also the generator. They must have a good ground or you wouldnt have the generator charging at all.

Model H charging system

Stumpy

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Anonymous-0

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Stumpy

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CNKS

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Janicholson

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John T

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Anonymous-0

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