Industrial loads behave differently

A motor draws several times its rated current when starting. A regulator sized on the rated current will either trip on starting or, worse, hold the voltage down during the start. Industrial AVR selection therefore starts from the load characteristic, not the rating.

What to establish

Whether the loads are predominantly motor, resistive or electronic

The largest motor starting current, and whether motors start together

Whether the supply is three-phase and whether the load is balanced

The worst-case input voltage and how long it persists

Whether the regulator will run continuously or only during poor supply periods

Regulator types for industrial duty

Servo-motor regulators for large loads with a wide correction range

Static regulators where speed of correction matters more than correction range

Combinations where two stages are used for a very wide range

Protection and bypass

Industrial installations need a bypass arrangement so the load can be fed while the regulator is serviced, and protection against over- and under-voltage on the output.