Starters and variable speed drives for slip ring motors

Since 1984, Electrodrives has been a pioneer in Liquid Resistance Starters (LRS) and Slip Energy Recovery drives (SER drives) for slip ring motors.

Today, our large experience and cuting-edge designs make us the industry leader, offering the most sophisticated solutions on the market.

Why Slip Ring Motors? The Hidden Advantage

Slip ring motors, often overshadowed by their more common counterparts, have a number of advantages that make them the ideal choice in several industrial applications.

Superior Starting Capabilities: Unlike standard motors, slip ring motors offer high starting torque with low starting current. This means smoother starts, less stress on your system, and a longer lifespan for the motor.

Unmatched Energy Efficiency: Combining the motor with a Slip Energy Recovery drive (SER drive), the system reaches the highest efficiency achievable for electrical motors in variable speed applications, as the SER drive is capable of recovering the slip energy from the motor and effectively redirecting it back into the grid.

Durability in Harsh Conditions: Built to withstand tough environments, these motors are less susceptible to wear, and tear compared to others. This resilience translates to fewer downtime.

Discover our range of products


Control and protection device for wound rotor motor with advance communications


Second generation of liquid resistance starter for wound rotor motor with speed and torque control


Slip Energy Recovery drive design to control the wound rotor motor speed in constant torque applications


Slip Energy Recovery drive design to control the wound rotor motor speed in quadratic torque applications

Energy management systems


Electrodrives design and manufactures the necessary equipment to balance the reactive power and power quality requirements to comply with IEEE 519 recommendation in your plant. This includes:

  • Fixed Medium Voltage Capacitor Banks
  • Multi-Stage Automatic Medium Voltage Capacitor Banks Static Var Compensation (SVC)
  • Static Var Compensation (SVC)
  • Medium Voltage Harmonics Filters

Latest News


FlexStarters Flex+60 Duo and Flex+25 for SAG and ball mills successfully completes FAT

We are pleased to announce that we have successfully completed FAT testing for the Flex+60 Duo and Flex+25 liquid resistance starters, designed for implementation in the SAG and ball mills at a mine in southern Africa. These units have passed rigorous quality and performance tests at our facilities. In addition,...

Execution of the RotorProtek project

ELECTRO DRIVES, S.L. announces the successful conclusion of the RotorProtek project, a technology aimed at the protection and monitoring of the starting control of wound rotor motors. This initiative found financial support by the Center for Industrial Technological Development (CDTI) and co-financed by the European Regional Development Funds (ERDF). The project...

Electrodrives presents its innovative control RotorProtek® in the SAG Conference

A few months after the launch of the innovative RotroProtek® control, Electrodrives showcases the potential of the new device at the SAG Conference in Vancouver. Thousands of mineral processing experts gathered at the eighth edition of the SAG Conference to discover the latest technology that will elevate comminution towards a...