Patent ID: 8502485

Claim:
A motor circuit comprising: a positive supply rail for connection to a positive side of a battery, a negative supply rail for connection to a negative side of said battery, a motor control circuit which generates control signals, a motor drive circuit comprising a plurality of motor drive subcircuits which each selectively permit current to flow into or out of a respective phase of a multi-phase motor connected to said motor circuit in response to said control signals, a switching means comprising at least one switch which is in series with a respective phase of said motor and a respective subcircuit which is normally closed to permit a flow of current to and from said subcircuit to said respective motor phase, a fault signal detector for detecting at least one fault condition and in the event of a fault condition being detected causing at least one of said switches in at least one phase of the motor to open, and a snubber circuit which is associated with said respective one of said phases of said motor, said snubber circuit being so arranged that following the opening of said at least one switch energy stored in said motor windings is diverted away from said switching means through said snubber circuit to said battery such that the rise in voltage across said switching means that occurs due to inductance of said respective associated motor phase winding does not exceed a predetermined level.