The Ford Barn - View Single Post - Can the alternator run the car by itself?

Willie Krash · 10-24-2012, 09:56 PM

The alternator if one wire will use residual magnetism in the rotor pole pieces to turn the alternator on regardless of battery. I don't believe a 10si one wire alternator has secondary regulation. Without seeing a battery the alt will go high and more so the faster it spins. As some point the coil will shut down from the high voltage and as the car slows the voltage will drop and the coil will fire.....all that unburnt gas...Pow.
Check your brake light. May be blown. That's my take.
BTW the residual magnetism is very weak and this why after sitting all winter the alt may be slow to turn on. As the alt speed increase more lines of force are induced into the stator. Once the voltage rises the VR clamps down and basically goes into a regulated feedback loop.
What you saw on the amp gauge were the loads, not the battery.

10-24-2012, 09:56 PM	#8
Willie Krash Senior Member Join Date: Jan 2012 Location: Phoenix, Oregon Posts: 661	Re: Can the alternator run the car by itself? The alternator if one wire will use residual magnetism in the rotor pole pieces to turn the alternator on regardless of battery. I don't believe a 10si one wire alternator has secondary regulation. Without seeing a battery the alt will go high and more so the faster it spins. As some point the coil will shut down from the high voltage and as the car slows the voltage will drop and the coil will fire.....all that unburnt gas...Pow. Check your brake light. May be blown. That's my take. BTW the residual magnetism is very weak and this why after sitting all winter the alt may be slow to turn on. As the alt speed increase more lines of force are induced into the stator. Once the voltage rises the VR clamps down and basically goes into a regulated feedback loop. What you saw on the amp gauge were the loads, not the battery.