Slip-Ring Motor Starting Panels (Rotor Starter)

Slip-Ring Motor Starters are part of the series of resistors applied to rotor circuits in order to control the speed/torque characteristics of a motor.

Rotor starters are mainly used for motor startup applications requiring high-starting torque, such as loaded belt conveyors in the mining industry. By using external resistors, it is possible to shift the motor’s maximum (break-down) torque up to the starting torque point for motors under heavy loads during start-up. The resistors are split into steps and controlled via contactors by a motor startup control system. As the motor speed increases, the external rotor resistors are eliminated by shorting contactors until all external resistors have been shorted out.

Slip-ring motor starters are made in two types: dry- or oil-immersed.




  • Fans
  • Pumps
  • Conveyors
  • Crane systems
  • Mill application
  • Mixer


Technical Specifications
Resistor types Dry- or oil-immersed
Type of construction Metal enclosed / metal clad
Rated voltage Up to 15kV
Rated Current Up to 1600A*
Ambient Temperature -30°C to 55°C
Control Digital controller based on motor current or time-relay

Motor protection relay

*For higher values, consult factory.