12 volt conversion

My H has been converted to 12 volts neg. ground.it has a 12 volt coil marked use with external resistor only.it has a resistor between the coil and the distributor.a mechanic friend says the resistor should be between the ignition switch and the coil.whitch is right? thanks. Jim iowa.

Should be between the ignition switch and the coil so it drops the voltage to the coil. Hal

I agree with Hal, thats where I would put it (between IGN Switch and coils input)

We had a longgggggggg discussion on this a good while back with some saying it doesnt matter, but I still prefer it before the coil, I just done went n forgot my theory by now lol

John T

Generally, the resistor is placed ahead of the coil.

However,

Just don't think it really much matters much.

The coil as well as the resistor is gonna take it's own voltage drop across a DC series circuit, no matter what, and neither really cares where it lives.

On this side of the tracks or that.

Just like hooking two light bulbs in a series circuit. Doesn't matter a fig where they are placed. :>)

Allan

(quoted from post at 09:01:38 11/19/10) Generally, the resistor is placed ahead of the coil.

However,

Just don't think it really much matters much.

The coil as well as the resistor is gonna take it's own voltage drop across a DC series circuit, no matter what, and neither really cares where it lives.

On this side of the tracks or that.

Just like hooking two light bulbs in a series circuit. Doesn't matter a fig where they are placed. :&gt

Allan

Click to expand...

Hmmm, I guess by placing the resistor between the coil and the points WOULD keep the points from burning up, but wouldn't the coil still get hot? I'm a bit confused, as always.

I think it was a very contentiopus discussion. I believe it is important to have it between the ign sw and coil. My logic is founded on two ideas. The first is that the coil and condenser act as a spring for electrons between them as the coil collapses on trigger. (I do not want a resistor between these two active elements, even if they are in a series circuit with all other components through the battery and ground.
The second is that some resistors are coils of nichrome wire that could make a magnetic (incremental) change in the flow of charge during collapse and current dampening in prep of switch closing on the trigger. Jim

Look under the hood of a classic car from the 50ies and the 60ies and see where the resistor is located. Between the switch and the coil. Your Question is answered.

(quoted from post at 09:23:03 11/19/10) I think it was a very contentiopus discussion. I believe it is important to have it between the ign sw and coil. My logic is founded on two ideas. The first is that the coil and condenser act as a spring for electrons between them as the coil collapses on trigger. (I do not want a resistor between these two active elements, even if they are in a series circuit with all other components through the battery and ground.
The second is that some resistors are coils of nichrome wire that could make a magnetic (incremental) change in the flow of charge during collapse and current dampening in prep of switch closing on the trigger. Jim

Click to expand...

Alrighty then. And all this time we thought these old tractors were simple, but what you stated does make sense.

Condenser between coil & points would interfere with coil performance by slowing down the magnetic flux buildup & collapse resulting in less voltage available for the spark plug.

Rusty, its still a series circuit (regardless where ballast is located) and the voltage dropping (12 to 6) current reducing (8 amps to 4 amps) ballast drops approx 6 volts leaving 6 across the coil sooooooooooooo regardless where its located NOOOOOOO the coil wont overheat. That part (overheating or too much coil voltage) is NOT the concern.

Buttttttttttttt when the points just break open theres some interaction ringing going on between the condensor and coils primary and if the ballast is there in between it changes the dynamics to some degree such that there may be less energy for discharge across the plugs gap.

This help or make it worse lol

John T

Yep, its all comin back to me now. Right as the points open theres some ringing and interaction going on between the condensor and coil so if the ballast is between them the dynamics change with the result there may be less energy transferered over to the secondary for discharge across the plugs gap.

Something like that, regardless I WILL PLACE IT AHEAD OF THE COIL

John T

Not sure I follow you Wayne. The Condensor is IN PARALELL with the points. When they are closed the condensor is shorted out and discharged and when they are open the condensor is in series with the coil and ground or any series ballast that may also be in the LV primary circuit. For sure, the coil will still fire without any condensor but I agree the sparks weaker. If the condensor is too small the sparks weaker and the poinst burn up sooner, if its too big she wont fire at all but the poinst last a longgggggggg time lol, if its just the right size the sparks the strongest.

Yes youre right it has to do with controlling the rate of the magnetic field collapse but your statement "condensor between coil and points" cornfused me, did you mean "resistor" between coil and points ??????? If youre like me the fingers n brains arent in sync and I mis type stuff like that often grrrrrrrrrrr Im gettin oldddddddd I reckon

Best wishes, John T

Thanks alot,i will wire it so its ahead of the coil,cause sometimes it wont start. Jim Iowa

One thing about locating the ballast resistor between the ign. switch and coil--- don't make the stupid mistake I made in haste on my M and bolt it to the bracket under the fuel tank. I was in a hurry and lookiing for an easy spot to put the thing, and there was an empty hole in a bracket under the fuel tank--- the primary wire from the switch to the coil ran right past it, so I thought, "wow, what a great place to put the resistor." Later on it dawned on me that this is directly below the filler neck on the tank, and if you overfilled or just spilled fuel while refueling, the spilled fuel would wind up directly on that possibly very hot resistor. I changed it immediately.