MAGNETIC BEARING DEVICE AND TURBO-MOLECULAR PUMP DEVICE

摘要

A magnetic bearing control device and a turbo-molecular pump device which can stably control the position of a body to be floated to an aimed position even when the length of a cable connecting a magnetic bearing to a controller changes. In the magnetic bearing control device composed of an electromagnet which supports the body to be floated in a floating state, sensors (Z1 and Z2) which measure the floating position of the body, and a controller which supplies sensor signals and an exciting current to the sensors (Z1 and Z2) and electromagnet through cables so that the electromagnet may support the body at a prescribed position in a floating state based on the signals of the sensors (Z1 and Z2), the controller is provided with a signal source (11) which supplies AC signals to the sensors (Z1 and Z2) and a sensor driving circuit (12) which supplies the signals from the signal source (11) to both ends of the two sensor elements (Z1 and Z2) arranged near the electromagnet and connected in series through cables (C), and the capacitance which is created by the lengths of the cables (C) is canceled by arranging the cables (C) in a balanced state. The control device can be constituted in a turbo-molecular pump device in which the controller is integrated with a pump main body.