Genset Controls

Automatic voltage regulator

AVRs for generator alternators. Send the alternator make and model as well as the AVR's own number. The regulator has to suit the alternator, not the engine.

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What to send us

The number stamped on the old part is the quickest route. If it has worn off, the engine or genset model and serial number usually gets us there. Photos help more than descriptions.

We cross-check whatever you send against the OEM catalogue and confirm the match with you before anything ships.

About this range

The AVR holds the alternator's output voltage steady. It compares the terminal voltage against a setpoint and adjusts the excitation current to the field, continuously, as load comes on and off. Everything the set feeds depends on it doing that quietly in the background.

Failures fall into three shapes. The set runs at the right speed but produces no output, which usually means it has lost excitation. The voltage wanders, lights dim and brighten, and bulbs and electronics fail early. Or it fails wide open and sends the voltage high, which is the dangerous one, because it takes connected equipment with it. A scorched or swollen board is worth looking for before testing anything else.

AVRs are matched to the alternator, not to the engine. Send the alternator make and model along with the number off the existing regulator. We carry the Stamford SX440, SX460, AS440 and MX341 pattern, the Leroy Somer R230, R438, R448 and R450 pattern, and Crompton and Kirloskar units.

Products in this category

8 listed

Open one for its specification and the part numbers it covers. We stock more than we list, so send us the number even if yours isn’t here. You can also look a number up in the part number index.