摘要 |
<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type motor that can improve both efficiencies at low-speed operation and high-speed operation, that is low-cost, and that has a high reliability to temperature rise. <P>SOLUTION: A permanent magnet type motor is driven at variable speed using an inverter, and uses a rare-earth magnet for a permanent magnet of a rotor. The permanent magnet type motor is put under an environment where a temperature of the permanent magnet at high-speed operation becomes higher than that at low-speed operation. A temperature coefficient of a residual magnetic flux density of the permanent magnet arranged in the rotor is in a range from -0.6 to -0.2%/°C. <P>COPYRIGHT: (C)2012,JPO&INPIT |