Farmall H generator amperage

redandgreen · Sep 11, 2013

I am working on my late grandpa"s H. After start up, I can give it a little throttle, and the needle on the amp gauge comes up and stays up, but usually only about 3 amps or so. This is fine usually, but when I turn the lights on, the needle deflects to discharging. Is there a way to turn up the amperage on this generator to get it charging more with the lights on? For some reason, I recall someone saying you can adjust the position of the brushes in the case to increase or decrease charging amperage. This tractor does have a switch on the "dash" for high or low charging rate. It only charges 3 amps when set to high. Connections have been cleaned just recently to fix a starting problem. This tractor is still on 6 volt, and does not have a distributor. We don"t really do much with the tractor as its a show tractor mostly. It does have the odd pulling job around the property though, so it still gets used.

Is there anything else I should check? Is there something with the switch on the "dash" that would keep the generator from charging fully? Thanks for the help.

Janicholson · Sep 11, 2013

Yes.
The third brush in the generator is probably adjustable. This adjustment limits the high charge rate. To put out moe voltage/current, set the adjustment closer to the fixed brush (closest to it). If still no joy, make sure the gen belt is tight enough (like a car belt) and the regular big fan belt is not way too loose (1.5inch deflection with hard thumb pushing is OK, less movement is OK to 1.25) too tight and waterpump bearings go out.
A sure way to tell if the gen can put out enough (and if there is too much resistance in the Field wire going to the light switch or resistance in the light switch ground) is to ground the F terminal on the gen with a jumper, then start it and run it at 3/4 throttle. If it charges plenty then, replace the Field wire going to the switch with 12ga, and clean the connections and grouinding of the light switch, and the box, and the pedistal. Resistance in teh ground can be troublesome. When charging at 3/4 throttle into a charged battery, the voltage should be 7 to 7.2. Jim

redandgreen · Sep 11, 2013

Thanks for the help. I"ll have to check ground on the case and pedestal then. We"ve already had to make a ground wire from the switch box cover to the side of the box. May take another wire out of the box to a clean ground on the chassis. Then I"ll check the brush position. Thanks again.

Bob M · Sep 12, 2013

Adding just a bit to Jim's excellent advice: With lights off a healthy generator should charge 14 - 18 amps at full throttle; with lights on "bright" about 3 - 4 amps.

gene bender · Sep 12, 2013

You have ground or it wouldnt show charge. I would get the generator serviced cleaned and new brurhes does wonders. I work with these system as seems noone knows how to make them work just want to go to the alt route. Just fixed one yesterday that didnt charge problem brushes were stuck. Cleaned armature and slots new brushes and a bushing and charges like new again.

John T · Sep 12, 2013

Good tips from Jim and Bob, here are a few other tid bits:

Sometimes carbon or oil or crud on the commutator causes weak charging, clean that commutator up see if that helps.

If the brushes are worn down too short or the hold down coil springys are weak, dirty or sticking that can reduce the charge, clean and exercise and light lube them

Insure the LHBD switch HAS A GOOD CLEAN FRAME CASE GROUND, try a jumper to insure then see if charge increases. As noted see how much she charges if you take a jumper and ground the gennys FLD post?? If its good then but weak otherwise, that tells you the genny and its brushes etc are all okay so the LHBD has a poor ground or is bad or the wires bad from FLD on genny up to the switch.

If the battery has a problem (have it load tested) even a good genny cant pump much charge into it ya know

John T

Jim Becker · Sep 12, 2013

(quoted from post at 04:26:58 09/12/13) Adding just a bit to Jim's excellent advice: With lights off a healthy generator should charge 14 - 18 amps at full throttle; with lights on "bright" about 3 - 4 amps.

The 14-18 figure is about right of you have a regulator type system. If it is cut-out style, 11 amps or so is about it. If a cut-out system is running higher than that, the third brush should be backed down to reduce the output.

redandgreen · Sep 12, 2013

The regulator/cutout is mounted on the generator itself correct? Its been a while since I dug into this tractor and can't remember. I know the Super C has the regulator mounted under the generator, and the 504 has a regulator mounted near the steering console. I'm pretty sure its got a regulator and not a cut-out, but I'm not 100% sure. I'm only able to work on tractors a couple days a week, and I have other priorities now. Got a nail in one of the brand new tires I put on my Grandpa's other tractor, a 35 John Deere A. Sat all last weekend at a show in Booneville, MO. Planning on taking that tractor to another show in a couple weeks and need to get it fixed before then.

Thanks again for all the help. It may be a fall or winter project after the shows are done for the season. So many projects, not enough time.

redandgreen · Sep 23, 2013

Well, got to work on the H today. Tried
everything. Moved the brush closer to the
closest fixed brush (the one with the wire
going to the Armature terminal, not the
bush that's grounded) and gained a whole
amp. Charged at 4 amps according to the
gauge. Tried cleaning generator mounting,
cut out mounting, field and aramture
terminals on cut out and generator. That
helped a bit. Got it up to 6 amps. Tried
running a new field wire, actually got
worse amperage - around 4 amps using 12 ga
wire. Tried dedicated ground from box to
positive post of battery, still 4 amps.
Think I might get a new harness. Found a
bunch of bare spots through the original
cloth insulation. Is six amps all I'm
going to get out of it at 3/4 throttle?
With the lights on high beam, it still
shows discharging at about 4 amps or so.
Better, but not ideal I would think.

Owen Aaland · Sep 23, 2013

Depending upon which generator you have the specifications are as follows:

Gen # 1101423 .... 9 - 11 amps, 7.3 - 7.6 volts at 2200 rpm
Gen # 1100501 .... 16 - 19 amps, 6.9 - 7.1 volts at 2500 rpm
Gen # 1101335 .... 9 - 11 amps, 7.3 - 7.6 volts at 1900 rpm

Note: The speeds listed are generator speeds not engine speeds.

The ammeter on the tractor will not show the actual generator output unless you have a magneto. Otherwise some of the amperage is drawn off before going through the gauge to run the ignition system.

redandgreen · Sep 23, 2013

(quoted from post at 22:51:21 09/23/13) Depending upon which generator you have the specifications are as follows:

Gen # 1101423 .... 9 - 11 amps, 7.3 - 7.6 volts at 2200 rpm
Gen # 1100501 .... 16 - 19 amps, 6.9 - 7.1 volts at 2500 rpm
Gen # 1101335 .... 9 - 11 amps, 7.3 - 7.6 volts at 1900 rpm

Note: The speeds listed are generator speeds not engine speeds.

The ammeter on the tractor will not show the actual generator output unless you have a magneto. Otherwise some of the amperage is drawn off before going through the gauge to run the ignition system.

As soon as I posted that last one, I tried one other thing. I cleaned the connection between the switch and box and ran it. Right away I got 10 amps on high at half throttle. With the lights on high, it shows no discharge or charge. This is a magneto tractor. Still want to get a new wiring harness tho.

Farmall H generator amperage

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Janicholson

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