[DannoXYZ]

Originally Posted by Triple Jim

Permanent magnet alternators do not suffer from overcurrent when the regulator shunts current to ground. They also to not require more engine torque to turn them when shunted. I first discovered this when testing regulators that I manufacture, using a variable speed motor driven motorcycle alternator in my bench test setup. The torque required to turn the alternator is actually least when its output is completely shorted. This is because very little electrical work is being done when the output voltage is zero and current is limited by the permanent magnet field.

How can output voltage be zero when engine's spinning at 4000rpms? The magnets aren't adjustable like automotive alternators.