| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum pump capable of reducing harmonic components in a motor current and an electromagnet current.SOLUTION: The vacuum pump includes a rotor, a motor 36 to drive the rotor, a magnetic bearing to support the rotor by magnetic levitation, an exciting amplifier 100 to supply drive current to the magnetic bearing, a DC power source 42B with variable output voltage, and a controller 44 to PMW-control the exciting amplifier 100. The controller 44 determines the amount of a bearing load, and sets the output voltage of the DC power source 42B lower as the bearing load is lower. As a result, the harmonic components in the bearing current can be reduced under a low bearing load. |
