Resistance Chopper Starter

Resistance Chopper Starter

There are some applications with Wound Rotor Induction Motors (WRIM) requiring an improved starting behavior compared to the standard performance provided by the Liquid Resistor Starter. In those cases, the Resistance Chopper Starter (RCS) provides additional performance.

Precise control of acceleration torque. Resistance Chopper Starters can be programmed with customized accelerating torque, providing a smooth start with a current ramp. This has two main benefits: it gives an extra protection to the mechanical parts of the drive train (electrical motor, pinions, gearboxes, etc.) and it also smooths the power demanded during the start, providing a progressive increase of current which helps to reduce the voltage dip at the plant.

Precise load sharing. Although our Liquid Resistor Starters produce a very good load sharing, there is no dedicated control to ensure that the torque of both motors is identical during the complete starting process. The Resistance Chopper Starters controls the starting current in all motors at the same time to ensure that the unbalance between the motors is lower than 1%. Unsymmetrical grid voltages, different wearing on mechanical components of the drivetrain, etc. does not result in any current unbalance between the motors.

RCS are commonly used in starting dual pinion mills as well other critical slip ring motors (i.e. pony motors of hydro-pumped plants, very large motors, etc).