Wound Rotor Motor Starters

Wound rotor motors are typically used in application requiring high starting torques, a limited number of operating speeds, or a stepped acceleration to achieve a soft start. Typically, existing applications utilize an electro-mechanical starter on the stator, and introduce multiple stages of resistance in the rotor via a contactor arrangement to achieve a soft ramp.

With MX3-based starters, wound rotor control is greatly simplified. The wound rotor starter consists of two main major sections:

1. A solid-state stator control, and
2. Secondary resistors into the rotor circuit from a separate 3-phase resistor bank.

This design achieves the high torque required by the application, with low inrush, while providing a smooth stepless start … greatly reducing the maintenance cost of the typical electro-mechanical control.