Redundant field drive for an electric machine

An electric machine comprising:

• an alternator;
• a regulator having a normal field control and a redundant field control each being coupled to said alternator;
• a means for determining and indicating whether said normal field control is not operative;
• and
• a selector for selecting between said operational field control and said redundant field control, said selector being responsive to said means for determining.

A method for providing excitation to an electric machine in an electric power generating system with an alternator and a regulator with a controller executing the method, comprising:

• receiving a field default signal indicative of an inoperative normal field control;
• receiving a normal field command responsive to said normal field control, indicative of a desired duty cycle command to a field coil of the alternator;
• formulating a default field command responsive to a selected value for a supply voltage;
• selecting and transmitting a field drive responsive to said default field command to a field coil of the alternator if said field default signal is asserted;
• and
• wherein the regulator includes an normal field control and a redundant field control.

An electric machine for providing a source of electrical power, comprising:

• an alternator;
• a first means for determining and providing an excitation to a field coil of said alternator;
• a second means for determining and providing an excitation for said field coil of said alternator, said second means providing said excitation if said first means is inoperative;
• and
• a means for determining whether said first means is inoperative.

A regulator for providing excitation to an alternator in an electric power generating system, comprising:

• means for receiving a field default signal indicative of an inoperative normal field control;
• means for receiving a normal field control signal responsive to said normal field control, indicative of a desired duty cycle command to a field coil of the alternator;
• means for formulating a default field command responsive to a selected value for a supply voltage;
• means for selecting and transmitting a field drive responsive to said default field command to a field coil of the alternator if said field default signal is asserted,
• wherein said regulator includes an normal field control and a redundant field control.