Patent ID: 8054024

Claim:
A brushless motor comprising: a sensorless driving circuit arranged to drive the motor; a rotating body capable of being rotated about a center axis; a rotor magnet arranged coaxially with the rotating body; a stator disposed opposite to the rotor magnet; and at least one coil wound around the stator; wherein the sensorless driving circuit is configured to drive the brushless motor according to a signal containing a third harmonic component relative to a fundamental wave component in an induced electromotive force; an amplitude ratio of the third harmonic component to the fundamental wave component in the induced electromotive force generated in the coil is about 1% or higher; and a rate of variation of a coil inductance equal to a ratio of a difference between a maximum coil inductance value and a minimum coil inductance value to the maximum coil inductance value is about 10% or higher.