Patent ID: 8149551

Claim:
A method for controlling a system comprising: determining whether a ground fault on a bus ( 110 ) operative to drive the system ( 100 ) exceeds a first threshold level; ( 502 ) receiving values of phase currents of a first motor; ( 504 ) calculating a sum of the values of the phase currents of the first motor ( 106 ) responsive to determining that the ground fault on the bus exceeds the first threshold value; ( 504 ) determining whether the sum of the values of the phase currents of the first motor ( 106 ) exceeds a second threshold value; ( 506 ) receiving values of phase currents of a second motor; ( 504 ) calculating a sum of the values of the phase currents of the second motor ( 106 ) responsive to determining that the ground fault on the bus exceeds the first threshold value; and ( 504 ) determining whether the sum of the values of the phase currents of the second motor exceeds the second threshold value ( 506 ).