Starting control for semiconductor inverter - detects excessive current flow and switches relevant transistor out of circuit predetermined interval

摘要

The starting control is for a semiconductor oscillator feeding a load such as an asynchronous motor, whose starting current is higher than its normal current. Each time a current limit, i.e. higher than the normal current consumed by the load, is reached, the semiconductor operating during a half-cycleof the output waveform is taken out of circuit, and is reconnected after a predetermined time has elapsed. The oscillator switches two transistors (1,2) alternately for each half-cycle of its output waveform. The currents passed by the collectors of the transistors are registered by a current sensor (6) and fed to a comparator (8), which detects any current above the predetermined limit. Under these circumstances, it triggers a monostable (9). This controls the drive stage feeding the transistor which is currently conducting, taking it out of circuit.