| 摘要 |
A fault in a gate turn-off thyristor (GTO) or a bipolar transistor is determined within the circuit, before an anode-cathode (collector-emitter) voltage is applied, by generating a gate pulse and monitoring the resultant gate (base) current. A fault in a gate turn-off thyristor almost always results in a short circuit between the gate-cathode terminals and between the anode-cathode terminals. The gate terminal can be interrupted in the case of other faults (idling state). The base-emitter path of a bipolar device can become faulty in a similar manner. Thus, the gate current which results from a gate pulse becomes abnormally large when the gate-cathode (base-emitter) terminals are short-circuited or the current is zero for an interrupted circuit or for a gate driver fault.
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