| 摘要 |
Provided are a compact and low-cost motor driver circuit capable of achieving an appropriate brake time and restraining heat generated by a regenerative resistance within a specific temperature range without employing a regenerative resistance having a greater capacity, a heat sink, or a FAN generating a larger volume of air, and a vacuum pump having the motor driver circuit. Regenerative current is controlled so that a speed characteristic gradually approaches inclination “a” from inclination “b” depending on the motor speed in the initial stage of regeneration. In addition, a limit is set not to pass further current when the regenerative current reaches a maximum brake current value Iset—brake—max. As stated above, when the motor is braked, control is performed so that the initial brake current value at the maximum rated speed is set low and the brake current is increased as the rotational speed decelerates.
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