METHOD FOR DIAGNOSING ABNORMAL CONDITION OF ISOLATION TRANSFORMER AND DEVICE THEREFOR

摘要

A diagnosis apparatus (20) mounted to a separable transformer includes an arithmetic control section (27) for inputting, through a differential amplifier (24), a signal smoothing circuit 25 and a voltage detecting section (26), a mutual induction signal generated in a primary coil (11) of the separable transformer when dc power from a do power supply section (21) and an ac signal from an oscillator (22) are applied to a capacitor (C) which cooperates with the primary core to form a resonance circuit. The arithmetic control section determines the presence or absence of a wire breakage or short-circuit failure in a secondary-side closed circuit of the separable transformer by comparing a frequency characteristic of mutual induction signal, determined based on mutual induction signals successively supplied thereto while the frequency of the ac signal from the oscillator varies, with frequency characteristics for normal, wire breakage and short-circuit conditions stored beforehand in a storage section (28).