lighting and amps

[sgtbull]

My "40 H is still 6 volt. Genny and starter have been rebuilt. New regulator and all wiring replaced w/ proper gauge. New Ammeter.
NOW, when the tractor is running w/o lights, it shows about 8 amps on the gauge. If I kick on the lights, it shows about -6 amps. Shouldn"t it at least still be on the positive side w/ the engine at nearly full throttle? What should I ck first? Its a three brush generator, so can this be resolved by moving the third brush? Have a tractor drive coming up, like the lights on for visibility, and really don"t want to become a pedestrian.

 

[Bob M]

Try moving the 3rd brush as close as possible to the nearest fixed brush. This will set the generator to it's maximum possible output. The regulator will then control the output current as required.

However if adjusting the 3rd brush does not help, suspect either a faulty regulator or a weak generator.

Note: A healthy generator should provide 3 to 5 amps of charge with all three lights burning on "bright" and the engine running at full speed.

 

[Anonymous-0]

Yes you can move the third brush closer. This will make the generator charge more you want about three bars between the two brushes when finished. Check the amps when the control is on Hi charge or the second notch. You dont need the lites on brite during the daytime as the dim position should be plenty.

 

[rustyfarmall]

On my 1940 H with the original cutout relay system I had to move the third brush down to where there is only about one commutator bar between the two brushes to get the proper amount of charge.

 

[John T]

Wow, thats a difference of like 14 (+ 8 to - 6) amps when the lights are turned on, I wonder if theres a minor high resistance short in your lighting circuit??? Have the lights on and dead ground the gennys field post with the engine at fast RPM n see what happens????? If its still - discharge (and theres no minor high resistance light wiring short), I suspect the genny is weak, may well be the brushes are worn down too short or else the brush hold down spring assemblies are weak/stuck/corroded, try to clean n light lube n exercise them and/or the commutator may be all oiled or carboned over which a good clean up may cure?? If she charges better when the fields dead grounded, then I suspect a VR problem like a faulty field current control relay or carboned n burned contacts. Id put a good direct ground on the VR also n see if that helps in case it has a weak resitive ground.

While adjusting the third brush closer to the fixed may well help, Id try the above first cuz short brushes or weak springs or a dirty commutator can cause a weak charge. Also try a good clean ground on the case of the VR and the gennys case/frame also in case its resistive.

John T

 

[Will Sick]

It is necessary that the switch box is grounded well. When you switch to high charge the generator field is grounded thru the switch box.

 

[NDS]

When we were running Hs and Ms at night back when they were new generators on some tractors would not put out enough amps to keep light burning all night. We were far from generator savvy and depended on IH factory and dealer mechanics so I do not know if generators could have been turn up.

 

[NDS]

When we were running Hs and Ms at night back when they were new generators on some tractors would not put out enough amps to keep light burning all night. We were far from generator savvy and depended on IH factory and dealer mechanics so I do not know if generators could have been turn up.

 

[Bob M]

That brings back memories from my early years spring plowing at night!

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Even in perfect condition those generator systems were marginal for working long hours in the dark. A few things we did to help run thru the night:

1 - Douse the lights at the end of each round (eg. when traversing the headland) to give the generator a moment to charge the battery.

2 - Operate the lights on the D(im) setting when possible. This provides BARELY enough illumination to see ahead. Yet the still brightly lit rear light provides adequate illumination of the implement.

2 - Fit the shortest fan and generator belts you can find, and run the belts as loose as possible without them slipping. This permits opening the adjustable fan and gen pulleys as far as possible, thus spinning the generator as fast as possible.

3 - Remove the commutator dust band from the generator so it runs cooler. (The hotter the generator internals the LOWER it's output). This however shortens brush/commutator life under dusty conditions.