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The VR9040 universal 40 amp voltage regulator is an electronic AVR which lets the alternator produce a fixed AC output voltage.

The device has an open chassis, resin molded design, and is intended to be mounted in the alternator’s connection box. Since there are no moving parts, it is able to withstand vibrating environments.

The device measures phase to neutral or phase to phase voltage of the alternator and adjusts the DC voltage applied to the excitation winding until reaching the desired voltage.

The unit offers low-frequency protection feature. A frequency measuring circuit continually monitors the generator output and provides output for low-frequency protection of the excitation system, by reducing the output voltage proportionally with frequency below a manually adjustable threshold. The nominal frequency can easily be changed to 50 or 60 Hz in the field by push-on link selection.

Sensing loss protection circuit terminates the excitation and protects the windings if there is no voltage on the sensing input.

The excitation power is derived directly from the generator terminals. The required minimum residual voltage for build up is 4 volts AC.

The output stage of the device is a Half Wave thyristor output with a free wheeling diode.

Basically the unit is compatible with all types of alternators. A stability adjustment potentiometer is also provided.

A ±3V analogue input is provided allowing external voltage adjustment.

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

An overload protection circuit limits the output current to its nominal value, preventing device failure under overload or short circuit condition.

• Part #: VR9040