HV thyristor bridge monitoring system - generates additional control pulse to which no address and so no output should correspond to check functioning of monitor

摘要

Trigger pulses are fed via a light guide (LA) to all thyristors and simultaneously to a counter whose output is compared with that of an address store. If parity exists an impulse passes to the supervisory unit which transmits a light signal via guides when a checking unit emits a coincident pulse indicating satisfactory operation of the thyristor. Each address is unique so that every thyristor is monitored in turn. To check that the monitoring circuits are functioning correctly an additional light pulse is generated at the input (L). The number of this impulse is n+1, but as the highest address is n there should be no corresponding output from the checking unit. The presence of output indicates a fault. Finally a reset impulse returns all counters to zero. By this means both thyristor and controls are cyclically checked.