LOAD CONTROL SYSTEM EMPLOYING SILICON CONTROLLED RECTIFIERS WITH OVERVOLTAGE PROTECTION AND COMPENSATION FOR LINE VOLTAGE FLUCTUATIONS

摘要

A control system for a load includes a pair of oppositely poled silicon controlled rectifiers disposed in parallel between a line and the load, each being provided with a drive circuit energized from across the rectifiers for triggering each silicon controlled rectifier at a predetermined time by discharging a capacitor via a control transistor. The triggering time is controllable. The triggering circuitry is empowered from the line whereby triggering also varies in a manner for maintaining a relatively constant output despite changes in line voltage. Each control transistor is additionally triggerable when the voltage across the pair of rectifiers reaches an excessive value, whereby the rectifiers are turned on alternately with each rectifier protecting the other.