Patent ID: 8723470

Claim:
A method of monitoring a motor having a stator, a rotor and a detector, the stator being operable to receive a driving signal to produce a first magnetic field, the rotor being operable to rotate in a circle, the rotor having a magnetic portion operable to emit a second magnetic field in a radial direction, the detector being operable to output a detection signal based on the position of the rotor, said method comprising: driving the motor with the driving signal such that the driving signal has a first amplitude; monitoring the detection signal; determining a first rotor angle θ 1 of the rotor relative to the stator based on the driving signal having the first amplitude and the detection signal; driving the motor with the driving signal such that the driving signal has a second amplitude; monitoring the detection signal; determining a second rotor angle θ 2 of the rotor relative to the stator based on the driving signal having the second amplitude and the detection signal; and determining the alignment of the detector relative to the stator based on the first rotor angle θ 1 and the second rotor angle θ 2 .