FAULT SENSING CIRCUIT OF ELECTRIC CAR

PURPOSE:To prevent successive breakdown of a thyristor by stopping operation of a chopper when the thyristor is broken. CONSTITUTION:A fault sensing circuit is formed by making a bridge connection of a luminous body 12a of a neon lamp, LED, etc., with thyristors 10a, 10b and volt resistors 11a, 11b which are connected in series. When the thyristor 10a or 10b is broken, voltage is applied to the luminous body 12a to be luminescent, and its luminous signal is inputted into a gate signal generation circuit 15 handling ON/OFF of the chopper by an optical fiber cable 13 having both functions of insulation and transfer media. The gate signal generation circuit 15 outputs a signal A to turn OFF a switch of the main circuit by the fault sensing circuit and a control signal B to turn OFF the thyristors 10a and 10b.