Generator AVR Stamford SX421 Automatic Voltage Regulator

SX421 is a three phase sensed Automatic Voltage Regulator and forms part of the excitation system for a brush-less generator.
In addition to regulating the generator voltage, the AVR circuitry includes a number of other useful 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 senses the voltage in the main generator winding and controls the power fed to the exciter stator and hence the main rotor to maintain the generator output voltage within the specified limits, compensating for load, speed, temperature and power factor of the generator.
A frequency measuring circuit continually monitors the speed of the generator and provides under-speed protection of the excitation system by reducing the generator output voltage proportionally with speed below a pre-settable threshold. A further enhancement of this feature is an adjustable volts per Hertz slope, to improve the response of turbo charged engines.
The AVR includes a stator over-voltage protection feature that directly trips a miniature circuit breaker to break the excitation circuit.
Provision is made for the connection of a remote voltage trimmer, allowing the user fine control of the generator's output.
An analogue input is provided allowing connection to a Newage Power Factor controller or other external device with compatible output.
The AVR has the facility for droop CT connection, to allow parallel running with other similarly equipped generators.