Resistor

Skipper_488 · Sep 28, 2018

My tractor has a 12 volt negative ground system. I was having some electrical issues so I decided to rewire the entire tractor. I also bought a 12 volt coil. Do I still need the resistor? Why or why not? what was it for originally?

Bob · Sep 28, 2018

Front-mount or side-mount distributor?

Square or round coil?

Skipper_488 · Sep 28, 2018

Side Mount, Round. It's a new 12 Volt coil instead of the original 6 Volt one.

JMOR · Sep 28, 2018

(quoted from post at 12:10:46 09/28/18)
Side Mount, Round. It's a new 12 Volt coil instead of the original 6 Volt one.

aybe help speed things along..................Bob wiil ask you whether it is a '12v, no external resistor required' or '12v, external resistor required'. If not marked on coil or if you don't know, then measure and state primary (small terminal to small terminal) resistance.

Bob · Sep 28, 2018

Make an part number of coil? Any statement printed on the coil "external resistor required"?

Any data available on the coil, specifically primary resistance?

Bruce (VA) · Sep 28, 2018

12v side coil never needs a resistor of any sort.

If you wanted to keep the 6v coil, you would need a resistor.

See tip # 30.

All N's w/ a 6v front coil came from the factory with the oem ballast resistor. It was rated at .3 ohms cold and 1.7 ohms hot.

It's purpose was to keep the running coil current below 4 amps. Otherwise, the coil would overheat.
75 Tips

Bruce (VA) · Sep 28, 2018

Oooops!

A 12v side coil with 3.35 ohms internal resistance does not need a resistor.

75 Tips

Skipper_488 · Oct 1, 2018

Thanks for all the help guys. I appreciate it.

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