MAGNETIC SUBSTANCE HOLDING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a processed object holding device with high reliability capable of preventing superposition of noise to a power supply current and holding a bearing made of magnetic substance always precisely at a defined position by balance of a suction force of an electromagnet. SOLUTION: Switching circuits 24 and 34 are driven at a duty ratio corresponding to a position of a bearing 3 and at mutually different on-off timing.