SX440 is a half-wave phase-controlled thyristor type Automatic Voltage Regulator (AVR) and forms part of the excitation system for a brush-less generator.
In addition to regulating the generator voltage,the AVR circuitry includes under-speed and sensing loss protection features. Excitation power is derived directly from the generator terminals.
Positive voltage build up from residual levels is ensured by the use of efficient semiconductors in the power circuitry of the AVR.
The AVR is linked with the main stator windings and the exciter field windings to provide closed loop control of the output voltage with load regulation of +/-1.0%.