1940 h charging

Anonymous-0 · Sep 24, 2011

Very original tractor with orig wiring that looks good. 6 volt gen cutout relay and 6 v pos ground. sanded all connections motor tested gen good cut out good voltage on both sides of ammeter took light switch box apart and off of frame to sand for good ground. ammeter shows discharge when non running and turn on lights shows charging when running on high setting with needle two clicks below 10a voltmeter shows 6.6 at battery. when running and i remove battery neg cable from batt the tractor starts to die and the current will jump between the two and shock you like elec fence. does tractor have to have batt to run or what is going on? also what is the little flat piece on the bottom of the light switch that has shiny alum colored metal wrapped around it? do i need 7.2 to charge?

David G · Sep 24, 2011

I am not an expert on the generators, but it would seem to me that a system with a cutout would require a battery. I think the field is energized when the cutout closes and deenergized when the cutout opens. The battery would act as a capacitor and smooth out the transitions.

John T · Sep 24, 2011

It needs the battery to work. Id expect battery voltage sitting there not running at 6.3,,,,,,,low charge and/or idle RPM's maybe 6.5,,,,,,,,high charge at faster RPM maybe 6.8 to 7 and a bit over volts.

John T
John Ts Troubleshooting

Janicholson · Sep 24, 2011

With respect, sorry David, the generator's field is continually grounded with the light switch charge rate connection in this case. The field gets its supply voltage from a third brush in the gen, or if a two brush gen, it is from the Arm terminal connected to the non grounded brush.
The light switch has 4 positions LHDB in HDB positions the F terminal is grounded directly. In L the field is grounded through a resistor on the light switch.
I think this system is in need of a third brush adjustment, If moved closer to the fixed Arm brush, it should make more like 7 volts, to 7.2v.
John T has provided the guide to make it work.
Just educating, Jim

David G · Sep 24, 2011

John,

I am very rusting on regulators and generators.

So it can run without a battery?

Janicholson · Sep 25, 2011

I never recommend operating a charging system with no battery. The stability of the voltage is fundamentally incremented to the battery voltage, but with no battery things get out of hand. It will ruin a alternator system and almost everything attached from over voltage if the battery cables are disconnected. Will it run with a generator and no Battery? Probably. should it be run W/O a battery no.
The worst is that very many individuals do not know the difference between a generator, and an alternator.
Our job on this forum is to keep melt downs from being endemic. Jim

1940 h charging

Anonymous-0

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David G

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John T

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Janicholson

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David G

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Janicholson

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