COIL CONTACT DETECTION OF INDUCTION HARDENING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a coil contact detecting method in an induction hardening device having a simple circuit configuration and high reliability. SOLUTION: In the induction hardening device 1, an entanglement and contact between a first coil 21 and a secondary coil 22 is prevented with a shield member 24 by arranging the shield member 24 grounded between the first coil 21 and the secondary coil 22 in a transformer 31. Therefore, an induction circuit 41 constituted of the secondary coil 22 and an induction coil 34 connected to the secondary coil 22 is allowed to be always in an isolated condition to a DC component. Then, the contact or non-contact of a material 35 to be heated to the induction coil 34 is detected by always applying a prescribed DC voltage from a DC power source 39 to the induction circuit 41 and monitoring the variation of the DC voltage.