John deere M 12volt help

ericblaich · Aug 4, 2014

I bought a JD M a few years ago that was converted to 12 volt before I bought it. I want to run new wires on it but I want to make sure everything is run correctly and I wont have problems. It has a Delco alternator on it currently with a 6 volt coil with a ballast resistor I plan on changing to a 12volt coil and removing the ballast resistor. any help or thoughts are appreciated.

James Howell · Aug 4, 2014

Take a look at the photos below of the wiring on "Audie" our 54 Model 40S.

Hope this helps.

ericblaich · Aug 4, 2014

it does what kind of resistor do you have on there?

ericblaich · Aug 4, 2014

and a stupid question what is the exciter switch

James Howell · Aug 4, 2014

Here is a link that briefly describes the <a href="http://www.ehow.com/facts_7512924_alternator-exciter.html">alternator exciter</a>.

Here is another link to a YT discussion about an <a href="http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=nboard&th=522140">exciter wire on an alternator</a> many years ago.

This link to a YT article on <a href="http://www.yesterdaystractors.com/articles/artint195.htm">[b:654c4848f0]Step by Step 12-Volt Conversion[/b:654c4848f0]</a> might also be helpful.

James Howell · Aug 4, 2014

Take a look at the photo below of the resistor used on all of our 12V tractors.

Hope this helps.

John T · Aug 4, 2014

"I plan on changing to a 12volt coil and removing the ballast resistor"

If youre changing to a full true 12 volt coil simply remove the ballast resistor and now the wire from the Ignition switches output (12 volts when ON) goes direct to the coils input which would be + terminal for a negative ground tractor.

The excitation circuit to Alternator is hot 12 volts when the ignition is ON which can be fed EITHER off the coils input or the ignition switches output (same place electrically). I usually place a 10 ohm 5 watt resistor in series in the excitation circuit (from coil or switch to ALTERNATOR) to prevent the tractor from running with ign switch off while some use a diode for that purpose.

The excitation circuit supplies voltage and current to the alternator to get it charging initially.

John T
Untitled URL Link

Steve@Advance · Aug 4, 2014

Good choice on the coil, go with a 3 ohm coil, a Napa IC14 or the Pertronix High Voltage 40511 will work without a resistor.

Do a search on the 10SI Delco alternator wiring, several examples to follow. The wire from the Bat terminal needs to be #10, the others can be #14 or 16. If you don't already have one, the plug that goes in the side of the alternator can be bought at the auto supply.

I like to solder and heat shrink all connections and tuck everything inside the black split harness wrap.

Now would be a good time to invest in an electronic points eliminator while you're in there.

John deere M 12volt help

ericblaich

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