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rotorwrench · 11-26-2019, 12:56 PM

Brand X (GM) actually had a bypass circuit to bypass the resistor or resistance wire so that it would have a full 12-volt while the starter was turning. Ford did that later to some extent but they had a different type solenoid than GM. The resistor will heat up as soon as the points are closed so they warm up almost instantaneously but it certainly controls the current by bleeding off what it doesn't need to function. The old Ford/Mallory coils only needed around 3 or 4 volts to function normally. Much more than that would burn them up. Can type coils can take a lot more heat so most never needed a ballast running on 6-volts. Modern insulating materials allow coils to take a lot more heat than they ever could before.

11-26-2019, 12:56 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: 12 volt coil with resistor Brand X (GM) actually had a bypass circuit to bypass the resistor or resistance wire so that it would have a full 12-volt while the starter was turning. Ford did that later to some extent but they had a different type solenoid than GM. The resistor will heat up as soon as the points are closed so they warm up almost instantaneously but it certainly controls the current by bleeding off what it doesn't need to function. The old Ford/Mallory coils only needed around 3 or 4 volts to function normally. Much more than that would burn them up. Can type coils can take a lot more heat so most never needed a ballast running on 6-volts. Modern insulating materials allow coils to take a lot more heat than they ever could before.