Patent ID: 8910631

Claim:
A method of detecting a fault in an apparatus for supplying breathable gas to a patient at a positive pressure, the apparatus including a gas flow generator comprising a servo controlled motor and impeller, a motor speed transducer configured to produce a motor speed transducer signal, a motor drive parameter transducer configured to produce a motor drive parameter transducer signal, a pressure transducer configured to produce a pressure signal indicative of the pressure generated by the apparatus, and a flow transducer configured to produce a gas flow signal, the method comprising: monitoring the motor speed in connection with the motor speed transducer signal produced by the motor speed transducer; monitoring the motor drive in connection with the motor drive parameter transducer signal produced by the motor drive parameter transducer; monitoring the pressure in connection with the pressure signal produced by the pressure transducer; monitoring the gas flow in connection with the gas flow signal produced by the flow transducer; following a predetermined duration, comparing: the motor speed to a first threshold to derive a first compared value, the motor drive to a second threshold to derive a second compared value, the pressure to a third threshold to derive a third compared value, and the gas flow to a fourth threshold to derive a fourth compared value; and determining a speed transducer fault condition in accordance with the first, second, third, and fourth compared values.