Re: Farmall A (4 position) switch getting too hot

Posted by Janicholson on May 23, 2006 at 17:33:41 from (66.173.50.166):

In Reply to: Re: Farmall A (4 position) switch getting too hot posted by MACE on May 23, 2006 at 12:39:09:

I'm goint to use some of your words and answer them as best I can.

All I do is touch the amp cover to the case (I do not put it on all of the way) and I get a 2 amp draw)
ANS: The cover is gounded, so it provides a path to ground for current that should not be there when the tractor is off.

When I disconnect the battery (I think your terminology is wrong, a heavy gauge wire is supposed to be connected to the Bat terminal of the cutout relay on the Gen, or the Bat terminal on the regulator if it has a three connection, or four connection Voltage reg. It attaches to the amp gauge on the opposite side to that of another big wire that goes to the starter switch battery side ) wire from the back of the switch.
Answer: The one that goes to the generator should be much smaller and hook to the F terminal of the Gen if it has a cutout relay, The voltage may be comming from a stuck cutout relay, or a generator with open brushes that is preventing correct cutout relay action. (there is a cutout relay inside a voltage regulator in addition to other control parts.)

then I know longer have a 2-amp draw.
ANS: This wire in not supposed to have voltage when stopped. This is the problem, more than likely. If the cutout relay, or voltage reg is malfunctioning, or wired incorrectly it will show voltage here. Path for the voltage is from the Brushes to the control switch L-H-D-B. The field on these generators is grounded to make field current flow through the one of the resistors on the SW when in L position, and through no resistor direstly to ground through the case when in the H position.

Ans:To check this possible generator fault, I would set it up so the current draw was happening, then disconnect the big bat connection down by the Gen. then reconnect it. If the draw returns, I think it is a stuck cutout relay. If it stops, and when reconnected stays stopped, I suspect generator problems. I hope this helps, lett me know, in a new post so it is fresh on the page.

Upon taking the switch completely apart the other day, I found that it has some sort of mechanical cutout internally when it is turned completly counter clockwise. It is in the round part of the switch.
ANS L= resistor in field circuit grounded through case. H= direct ground through case of field.
D= direct ground of field through case, and resistor (different one) in light circuit
B= no resistor in field, and no resistor in light circuit, thus Bright lights, and full charging.
I hope this works for you, I do not know if it is a regulator system or cutout only. If it has a real regulator, it should not use he L or H part of the switch and should be wired differently. Bob M's wiring diagrams will help to cure that issue.
JimN

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