Patent attributes
A gas laser apparatus includes: a magnetic bearing including an electromagnet capable of controlling a magnetic force, and configured to rotatably support a rotary shaft of a fan in a magnetically levitated state by the magnetic force, the fan being configured to supply a laser gas; an electromagnet control unit configured to control the magnetic force of the electromagnet based on displacement of a levitated position of the rotary shaft and adjust the levitated position; a motor configured to generate torque for rotating the fan; a magnetic coupling configured to couple the rotary shaft and a drive shaft of a motor with a magnetic attractive force and transmit the torque of the motor to the rotary shaft; an attractive force estimating sensor configured to detect a parameter that enables an attractive force of the magnetic coupling to be estimated; an attractive force measuring unit configured to measure the attractive force of the magnetic coupling based on the detected parameter; and a correction unit configured to correct the magnetic force of the electromagnet according to a variation in the attractive force measured by the attractive force measuring unit.
