| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a rotation speed and position of a rotor by using an easily-calculated signal of a current ripple of an electric motor. <P>SOLUTION: An electric motor includes at least one first brush 61 and at least one second brush 62, which are arranged in a stationary fashion and arranged to contact a commutator 30 that rotates with a rotor. The commutator 30 includes at least one cylindrical section with a circumferential surface on which a plurality of segments 32a, 32b, 32c and 32d are arranged with insulating sections interposed between them. In order to detect the rotating speed and position of the rotor, the electric motor includes brushes 61 and 62 with asymmetric circumferential widths or angles or a stator with an uneven magnetization. The electric motor is arranged to detect only one signal when the rotor rotates for an angle between two adjacent segments. <P>COPYRIGHT: (C)2013,JPO&INPIT |
