In a typical generator circuit, the field terminal is grounded inside
the regulator. When the generator is producing the maximum voltage
allowed in the system (usually 14.2 volts), then the regulator will
break the field connection to ground and make the field current pass
through a resistor to ground. This reduces the field current to the
point that the generator output drops. It then cycles back and forth.
If the regulator can't sense the generator output, it will leave the
field windings at full power. As the generator output rises with RPMs,
it will rise to the point that the field windings will burn out. The
other end of the field winding is connected to the armature output
inside the generator, so it will power itself to death. I've had bad
regulators go out and take a perfectly good generator with them.
Phil Roettjer wrote:
>
> Simon,
> I do agree that in the case with only the field wire connected that the
> voltage regulator may raise the voltage to the field to the point of burning
> out the field windings.
>
> Regards,
> Phil
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