A heavy-duty slip regulator for steel mill service

Slip regulators have been applied successfully to blooming mills as early as 1913 where the heavy impact load peaks of the mill motors would result in excessive power surges. An installation of this type often consists of a wound-rotor induction motor driving a flywheel motor-generator set. The secondary of the motor is connected to a slip regulator which automatically increases its resistance in case of heavy load peaks, thereby permitting the set to slow down and give up part of its stored kinetic energy. In this manner it is possible to supply high momentary load peaks to the mill motors with a practically constant power demand from the a-c supply.