So, I'm wiring up a Model H with starter and generator, but no lights. Referring to the wiring schematics on page 38 of the H parts pdf file on the Deere parts web site, does the light switch serve as sort of a junction block, connecting the green on yellow conductor from the "F" terminal on the generator to the ammeter, through the light switch and through lead numbered 11 on the upper diagram, 10 on the lower diagram? As I don't have a light switch, since there are no lights, should I connect the green on yellow lead, as well as the black on yellow lead from the relay "Bat" terminal both to the same post on the ammeter. If so, should I put a fuse in that green on yellow lead?
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The light switch serves as a charge level controller by presenting either (1) a direct short to ground of the wiring from the generator (F), or (2) a resistance of some 2-1/2 ohms in the circuit to the (F) terminal to ground.
The direct short provide a high-charge path – mainly for use when you have a lot of starts within a short span of time, or when using the lights. The low-charge mode is generally sufficient for normal use of the tractor, and will be best suited for your operation.
And so – using Figure 701 in your JD-H Restoration Guide as a reference, simply insert a resistor from generator (F) to Ground, and do not run any further wires form the F terminal. The resistor should be roughly 2-1/2 Ohms, and 10 watt will do. It may well be that even a 5-watt resistor will work here – whatever is on the light switch, that is what you need. I’d say try a 5-watt resistor, and if it burns up, replace it with one having a higher power rating. A burn-out here will not hurt anything!
Wiring – For your configuration, there will be no wire, generator (F) to light switch, no wire from light switch to ammeter, and obviously, no wires from light switch to the lights. In short, you have no light switch for wires to go to!
See JD-H Wiring diagrams at URL cited below. If in question still, call me at (830) 627-0430. (PatB)
Enhanced wiring diagram, JD H
The direct short provide a high-charge path – mainly for use when you have a lot of starts within a short span of time, or when using the lights. The low-charge mode is generally sufficient for normal use of the tractor, and will be best suited for your operation.
And so – using Figure 701 in your JD-H Restoration Guide as a reference, simply insert a resistor from generator (F) to Ground, and do not run any further wires form the F terminal. The resistor should be roughly 2-1/2 Ohms, and 10 watt will do. It may well be that even a 5-watt resistor will work here – whatever is on the light switch, that is what you need. I’d say try a 5-watt resistor, and if it burns up, replace it with one having a higher power rating. A burn-out here will not hurt anything!
Wiring – For your configuration, there will be no wire, generator (F) to light switch, no wire from light switch to ammeter, and obviously, no wires from light switch to the lights. In short, you have no light switch for wires to go to!
See JD-H Wiring diagrams at URL cited below. If in question still, call me at (830) 627-0430. (PatB)
Enhanced wiring diagram, JD H
Pat,
Couldn't I also just rotate the third brush in the generator to reduce the generator output? Looking from the back of the generator, in the direction of travel, which way would I rotate that brush to reduce the output. I don't really want to let the smoke out of my new wiring harness on the first start up!
Couldn't I also just rotate the third brush in the generator to reduce the generator output? Looking from the back of the generator, in the direction of travel, which way would I rotate that brush to reduce the output. I don't really want to let the smoke out of my new wiring harness on the first start up!
Leon, sounds like youre trying to mix apples n oranges here. Okay, on the older 3 brush generators that used a simple 2 wire Cutout Relay, they still needed a way to regulate the gennys charge rate and that was done by a light switch that has Low and High charge positions (as Pat explained for you) and wires to the gennys FLD terminal. The Gennys ARM terminal is what wired to the ARM/GEN terminal on the Cutout Relay while its other BAT terminal wires up to the Load (NOT battery/starter) side of the ammeter.
Its all well n good to still use the simple 2 wire cutout relay ifffffffffffff you had a method to regulate the gennys output !!!!!!!! It wont charge unless its FLD post is grounded and if you permanemtly ground it the battery can charge BUT it can get overcharged n boil over n be ruined. If you dont want a light switch (Id still use one even if you dont use the Lights portion) you would have to rig up a Low High switch that grounds the Field via an in line series resistance of around 3 ohms and 20 or so watts (a Power rated resistor) for Low charge but then dead grounds it for High Charge.
If you check with Jim at Agri Services in New York he can get you a Low High charge light switch that you can wire to the gennys FLD post so you can regulate the charge rate and NOT have to jury rig something and you dont really need any lights whatsoever SO MUCH EASIER N INEXPENSIVE
If you permanently dead ground the Field but back off the gennys charge rate via the 3rd brush adjustment, then it may not overcharge but it will be slow to recharge the battery. To lower the rate move the 3rd brush farther away from the fixed brush beside it, the closer the brushes the more the charge.
Again, so much easier to just buy a Low High switch n wire it right.
The wiring will be the Load (NOT battery/starter) side of ammeter wires to the BAT side of Cutout Relay,,,,,,,,,, the other GEN/ARM side of the relay wires to the gennys ARM post,,,,,,,,the gennys FLD post wires to the light switch (or whatever ground or jury rigged resistive ground you come up with)
Other option is to use a full fledged 3 or 4 terminal Voltage Regulator, no light switch required, n toss the old cutout relay..
Your tractor your call
John T
Its all well n good to still use the simple 2 wire cutout relay ifffffffffffff you had a method to regulate the gennys output !!!!!!!! It wont charge unless its FLD post is grounded and if you permanemtly ground it the battery can charge BUT it can get overcharged n boil over n be ruined. If you dont want a light switch (Id still use one even if you dont use the Lights portion) you would have to rig up a Low High switch that grounds the Field via an in line series resistance of around 3 ohms and 20 or so watts (a Power rated resistor) for Low charge but then dead grounds it for High Charge.
If you check with Jim at Agri Services in New York he can get you a Low High charge light switch that you can wire to the gennys FLD post so you can regulate the charge rate and NOT have to jury rig something and you dont really need any lights whatsoever SO MUCH EASIER N INEXPENSIVE
If you permanently dead ground the Field but back off the gennys charge rate via the 3rd brush adjustment, then it may not overcharge but it will be slow to recharge the battery. To lower the rate move the 3rd brush farther away from the fixed brush beside it, the closer the brushes the more the charge.
Again, so much easier to just buy a Low High switch n wire it right.
The wiring will be the Load (NOT battery/starter) side of ammeter wires to the BAT side of Cutout Relay,,,,,,,,,, the other GEN/ARM side of the relay wires to the gennys ARM post,,,,,,,,the gennys FLD post wires to the light switch (or whatever ground or jury rigged resistive ground you come up with)
Other option is to use a full fledged 3 or 4 terminal Voltage Regulator, no light switch required, n toss the old cutout relay..
Your tractor your call
John T
The 3rd brush faces another brush and if you remove the stop pin for max. output you keep it 1 and 1/2 bars away from the other brush no closer. SO if you move it as far as you can away from that brush it should go to it's lowest setting.
Hope this helps explain it right.
Hope this helps explain it right.
It is my opinion that your method for reducing charge rate is far more risky than my way. But it's your wiring!!!
The wise solution was explained to you in my earlier dissertation, but even more wise would be to install the light switch per design and (obviously) ignore wiring to the non-existent lights!!! (PatB)
The wise solution was explained to you in my earlier dissertation, but even more wise would be to install the light switch per design and (obviously) ignore wiring to the non-existent lights!!! (PatB)
Sure, the farther the 3rd adjustable third brush is awy from the fixed brush THE LESS THE CHARGE. But at real low charge rates it may be slow to fully recharge the battery. Thats why the new n improved full fledged Voltge Regualator came into style, to automatically control the rate of charge.
John T
John T
Guys,
Thanks for all the really good replies. I guess I'd be safe enough for a trial run to just ground the generator's "F" terminal. Then I'll maybe put in a resistor while I locate a light switch. I'm hesitating to put lights on mostly because original or original looking lights are pretty darned expensive and it's electric start that I'm after, no need whatsoever for lights. Of course lights would look good. Maybe someday if I have any retirement money left after the current financial fiasco ----
Thanks for all the really good replies. I guess I'd be safe enough for a trial run to just ground the generator's "F" terminal. Then I'll maybe put in a resistor while I locate a light switch. I'm hesitating to put lights on mostly because original or original looking lights are pretty darned expensive and it's electric start that I'm after, no need whatsoever for lights. Of course lights would look good. Maybe someday if I have any retirement money left after the current financial fiasco ----
Leon -- Just bear in mind that by grounding the generator's "F" terminal, you will have the strongest possible field current and thus the strongest possible generator output at its "A" terminal -- in the neighborhood of from 15 to 25 AMPs. "Putting a resistor in later" will be okay so long as you define "later" as something under (say) an hour's run time. A charge of that rate is not good for the batttery!
In the ordinary scheme of things, your light switch is part of the regulatory system, and by deleting it, you lose the ability to switch back & forth, from normal charge to high charge. This is the basis for John T's recommendation that you consider replacing the cutout relay with a voltage regulator. But I leave that notion up to you. For now, I'd go with the resistor from the git-go -- use 2.5 ohms at (min) 10 watt. (PatB)
In the ordinary scheme of things, your light switch is part of the regulatory system, and by deleting it, you lose the ability to switch back & forth, from normal charge to high charge. This is the basis for John T's recommendation that you consider replacing the cutout relay with a voltage regulator. But I leave that notion up to you. For now, I'd go with the resistor from the git-go -- use 2.5 ohms at (min) 10 watt. (PatB)
I got her fired up this afternoon. It charged at about the 10 amp rate with no resistor, but went into the "peg the needle" discharge mode when I shut it down. Finally, I discovered that the new after-market cut out relay I just bought was faulty. It's points weren't opening. Not too long ago at a salvage yard I picked up a couple of 50+ year old Delco Remy relays from generators that had most likely been on "A" or "B" tractors. Both relays looked pretty bad, rusted and corroded even inside. However, after I cleaned them up a bit, both worked OK! I wanted one of the original style on my H anyway. All I need to do is straighten out the curved mounting bracket so that it sets on the "perch" of the model H tractor.
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