Ballast resistor

ScubaChief60 said:
Should I be concerned about any back feed of voltage towards the ballast resistor during the brief period when the starter switch is depressed? Would a second diode here be a good idea to prevent 6 volt back-feed or does it not matter?
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I was just thinking the same.
I have a push button momentary switch to the coil instead of using diodes.

Glenn
 
The resistor will not care about 6 volt back-feed. It's used to that. Full 6 volts goes through the resistor every time the points open to stop current flow.
 
Kube said:
They will seem to run better as the coil is getting the full 6v. Run it like this for a while and you'll find it'll run worse than ever; a LOT worse. You will burn up the coil and / or points. No way around it.[/QUOTE

Henry put a ballast resistor in the circuit for a reason! The simple rule for a stock old Ford is..."starts on 6 and runs on 4".
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Excellent!

RE: "The resistor will not care about 6 volt back-feed. It's used to that. Full 6 volts goes through the resistor every time the points open to stop current flow."

You all are the best!
 
The Mallory/Ford design coils were rather unique in shapes and compositions compared to an ordinary can type 1.5 Ohm coil. They needed just a bit of current control from the power source to operate efficiently and reliably. As a general rule, the coils functioned very well unless current outside air temperatures were well below freezing. Batteries are taxed and thick engine & transmission lubricants don't help either. It's remarkable how well these old systems worked when they were new. As they deteriorate, they feel the affects and performance suffers.

I think the figure was around 0.8 Ohms as to the value of the ballast resistor on those old systems. In the 8BA era, the can type coils didn't need any current control for the Load-O-Matic systems.
 
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