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.