Patent ID: 7880448

Claim:
A control circuit for a permanent magnet machine (PMM) having a kinetic portion electrically coupled to a power conversion portion, said control circuit comprising: a switch disposed between said kinetic portion and output feeder cables of said power conversion portion; a first sensor effective to detect a first fault condition in one of said feeder cables and in said power conversion portion, said first sensor being effective to open said switch when a fault condition is detected; a motive shaft disposed between said kinetic portion and a prime mover, said prime mover effective to apply a first directional torque on said motive shaft; and a second sensor effective to detect a second fault condition in said kinetic portion, said second sensor being effective to apply a voltage to a winding within said kinetic portion generating an opposing second directional counter torque to said motive shaft wherein a combination of said torque and said counter torque exceeds a fracture yield strength of said motive shaft.