aMP GUAGE

MILLARD HAYES · Aug 29, 2021

This Super M will have a 2 wire alternator, but my question is do I have to know the amp before choosing a guage? I thought of using a 60amp instead of the D/C one that is on it. Amy advise somebody.

DeltaRed · Aug 29, 2021

Either/ or will work equally well.Just
use the old one if it still
works.Really,the only difference is in
how the face is painted.

John T · Aug 29, 2021

Some old tractor ammeters may only be 20 or 30 amp while an alternator can deliver much more which may cause a small meter to peg, reason
for using a bigger one.

John T

used red MN · Aug 29, 2021

Actually as an example you could put a 120 amp alternator on it but in general use the alternator will only put out what the demanded amp load is. The only time an alternator that large will ever charge anywhere near max amps is right after you cranked the engine a lot and it is trying to bring the battery voltage back up. The ideal alternator to use on one of these tractors is the one that puts out the lowest amps, in a Delco 10si that is a 37 amp unit. Not saying you have to change your plan of the alternator you are going to purchase. Disclaimer here is maybe you are setting this thing up as a tractor ride conglomeration with a large platform and an inverter for coffee pots and toaster ovens then you might need a huge alternator. The simple answer is use what you have, it may peg out for a bit after you start it and you have to crank it a bit because it did not pop right off. But after that it will register just fine.

Janicholson · Aug 29, 2021

Amp gauges used in tractors have a solid connection between the two terminals on the inside. This connection is called a shunt.
The shunt is a calibrated conductor with a specific current rating across its length. The meter movement that causes the needle
motion, Charge or Discharge, is connected across this shunt from each end, and measures a portion of the flow in parallel with the
shunt, but much less amps flow through the meter movement. The numbers placed on the gauge are a reflection of the intended
maximum amps the shunt can handle, and measure accurately. Sizing the meter to just greater than the output amps of the alternator
allows the meter to read with reasonable accuracy. Alternators are so good at voltage control, that most of the time, when
running, the meter will appear to be at zero. That is normal. Jim

John T · Aug 29, 2021

Youre right just because you have a 100 amp alternator it obviously don't pump that much all the time lol. If changing to an alternator I may replace an old 20 amp ammeter with a bigger unit like the poster is doing it will work fine.......

Best wishes

John T

BarnyardEngineering · Aug 30, 2021

(quoted from post at 11:33:12 08/29/21) Some old tractor ammeters may only be 20 or 30 amp while an alternator can deliver much more which may cause a small meter to peg, reason
for using a bigger one.

John T

If everything is in good working order the ammeter should not peg for more than a few seconds even if it's an old 20 or 30 Amp meter.

aMP GUAGE

MILLARD HAYES

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DeltaRed

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John T

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used red MN

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Janicholson

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John T

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BarnyardEngineering

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