Ammeter & Light switch properly grounded?

Patrick HMD · Aug 20, 2012

I'm redoing my ammeter box with new components. During disassembly I noticed a lot of rust inside, and it seems that the inside never ever received any paint. So as not to repeat that, I power brushed then spot blasted the whole box inside and out, then gave it a good heavy coat of primer. Now that I'm ready to mount the new ammeter and new light switch, am I to assume that they both have to be properly grounded to the box? I need to know for sure before I start scraching some of that heavy primer off where things make contact with each other.

Just trying to eliminate problems before they happen, and avoid starting one of those "My tractor won't start" treads. Who knows, it might happen anyway. Knock on wood. lol

TIA Patrick
'49M

Wayne in MN · Aug 20, 2012

Do not ground the ammeter!! It is wired direct to the battery!
The light switch is not grounded either; all terminals are "hot" at some time depending on switch position.

pete 23 · Aug 20, 2012

If you are talking about an old Farmall like H or M
with the high low charge on the light switch then
the light switch needs to be grounded to complete
the field circuit from the generator. If it has a
voltage regulator then the switch does not need
grounding and an ammeter must be fully insulated
from all ground.

Patrick HMD · Aug 21, 2012

That's exactly what I've got Pete. Here's the new switch I just got from Brillmans. Plenty there to ground too. And obviously, it is a 4 position for a cutout. I'm glad I asked, because I didn't have a clue. All this farmll stuff is a slow and gradual learning process for me. Not a day hardly goes by that I don't learn something new. Thanks guys.

Patrick
'49M

gene bender · Aug 21, 2012

The four position lite sw in that circut needs to be grounded to the case and then the case needs to be grounded.

gene bender · Aug 21, 2012

The sw will get a good ground where it fits thru the housing and the nut holding it fast those areas should be clean and then the stud holding holding the housing clean that area good so to make good contac with the steering post mite want to check to make sure the steering post also has a good ground.

pete 23 · Aug 21, 2012

I run a wire from the grounded end of the low charge
resistor of light switch, right on back to the generator. Then you
can forget about all those crappy grounding spots
from switch to cover, cover to box, box to post,
post to trans cover.

Janicholson · Aug 21, 2012

Th Light switch body indeed needs to be grounded to the chassis. I would only take it as far as a clean shiny steering support bolt at the deck, if you are unsure about the support to box connection. The Generator direct connection is (opinion) not needed as the generator will not charge unless its case is correctly grounded to the engine block. Jim

Ammeter & Light switch properly grounded?

Patrick HMD

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Wayne in MN

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pete 23

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Patrick HMD

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gene bender

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gene bender

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pete 23

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Janicholson

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