US Patent 9097767 DC-motor and fuel pump faults and brush-wear prognosis

A system and method for determining the health of a DC motor, such as a DC motor on a vehicle. The method includes measuring a current output signal of the DC motor, determining a mean of the measured current signal over a predetermined time period and determining a variance estimation of the mean of the measured current. The method then uses the variance estimation to determine the health of the motor, including an end-of-life prediction of the motor, and uses the mean of the measured current to determine the performance (torque) of the motor.