| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronous motor wherein production of electromagnetic noise during starting operation is suppressed and transition from starting operation to synchronous operation can be carried out with reliability. <P>SOLUTION: A microcomputer 22 turns off triacs SW1 and SW2 to interrupt a synchronous operation circuit 21. Further, the microcomputer controls first to fourth transistors 16 to 19, and causes a rectification bridge circuit 20 to carry out full-wave rectification to perform starting operation. When the number of revolutions of a permanent-magnet rotor 5, detected by an optical sensor 12, reaches close to the number of synchronous revolutions with respect to the power supply frequency detected by a power supply frequency detecting unit 24, the microcomputer turns off the first to fourth transistors 16 to 19 and turns on the triacs SW1 and SW2. Thereby, the microcomputer attempts switching operation to switch from a starting operation circuit 14 to the synchronous operation circuit 21, and thus carries out control so as to transition to synchronous operation. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
