METHOD OF DIAGNOSING FAULT OF COIL CURRENT SUPPLY CIRCUIT FOR LINEAR MOTOR

摘要

PURPOSE:To always diagnose trouble during the operation of a circuit by passing a current supply cable itself or only the earth wire thereof through a through type current transformer to take balance so that no large output appears in the current transformer and throwing off the balance at the time of the trouble of the cable. CONSTITUTION:A pair of current supply terminal 3 and a pair of current supply cables 7 are respectively connected to a coil 1 for a linear motor having a semiconductive outer shield 2 and each of the cables 7 consists of a cable conduc tor 4, an insulator 5 and a metal shielding sheath 6. All of them are collectively inserted in a through type current transformer CT 8. The sheath 6 is earthed on the side of the coil 1 by an earth wire 9. The supply current of the coil 1 is cancelled by input/output and does not appear in the CT 8 but, when the cable 7 generates dielectric breakdown at the part below the CT 8, a current flows in the sheath 6 to flow to the earth line 9 and is caught by the CT 8 to become the output thereof. This output is detected to be transmitted to make it possible to detect a fault during the operation of a circuit.