Two Phase Sensed Automatic Voltage Regulators For A Brush-less Generator

MX321 is a two phase sensed Automatic Voltage Regulator and forms part of the excitation system for a brush-less generator. Excitation power is derived from a three-phase permanent magnet generator (PMG), to isolate the AVR control circuits from the effects of non-linear loads and to reduce radio frequency interference on the generator terminals.

Sustained generator short circuit current is another feature of the PMG system.

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.

Soft start circuitry is included to provide a smooth controlled build up of generator output voltage. A frequency measuring circuit continually monitors the shaft 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 engine recovery time on turbo charged engines.

Soft start circuitry is included to provide a smooth controlled build up of generator output voltage. Uncontrolled excitation is limited to a safe period by internal shutdown of the AVR output device. This condition remains latched until the generator has stopped.

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 devices with compatible output.

The AVR has the facility for droop CT connection, to allow parallel running with other similarly equipped generators.