Discover our innovative line of second generation liquid resistance starter for wound rotor motors. It combines a robust design engineered for superior service life with the latest control technology that allows complete control and protection of all motor and drive parameters.

Starting a motor is now easier than ever with FlexStarter. Connect, monitor, maintain and configure everything directly from your smartphone, without the need for external software or apps. Additionally, the maintenance mode will allow you to perform simulated starts to check the moving parts inside.


Total speed and torque control

FlexStarter incorporates RotorProtek® offering full control of speed and torque during start-up, regardless of load, temperature, grid conditions, etc., for efficient management.

Full motor and gearbox protection

Active protection and conditioning monitoring functions to ensure safety against damage to slip rings, rotor windings and other mechanical components. Furthermore, it provides the ability to integrate protections against frozen charge, torque unbalance in dual applications among others, allowing a complete customization of the configuration according to the user's needs.

Delta electrodes arrangement

The innovative delta design of the electrodes improves stability during motion and eliminates torque and current unbalances existing in starters with in-line arrangement, prolonging the service life of moving parts and reducing equipment maintenance costs.

Interface FlexStarter LRS



FlexStarter® Type Flex 10 Flex 15 Flex 25 Flex 45 Flex 60
Tank capacity 1000 liters 2000 liters 2500 liters 4500 liters 6000 liters
Motor power (f=0.7…2 × In) 500…2400 kW 1000…3500 kW 1900…5800 kW 3200…9500 kW 4500…13000 kW
Max. rotor current 900 A 1000 A 2000 A 2100 A 2500 A
Max. rotor voltage 2500 V 3000 V 3500 V 4200 V 4200 V
Max. energy (@ 40ºC) 190 MJ 285 MJ 470 MJ 850 MJ 1130 MJ
Electrode material Stainless steel Stainless steel (optional bronze alloy in Flex+)
Turndown ratio 80:1 80:1 (optional 120:1 in Flex+)
Footprint (L x W) 1.25 x 0.98 m 1.65 x 1.40 m 2.10 x 1.70 m 2.85 x 2.00 m 3.70 x 2.25 m
Enclosures 3 cubicles: tank, HV panel & LV panel IP55 carbon steel (standard) or stainless steel
Electrodes arrangement Delta arrangement, spindle with variable speed (VFD), vertical movement
Shorting contactor 2-pole air contactor 3-pole bar contactor
Protection & control RotorProtek® (standard) and/or LS Electric PLC
Communications Wi-Fi AP 2.4GHz (configuration/service) + Ethernet IP, ProfiNet or Modbus (standard)
Electrolyte cooling Natural (standard), agitator Agitator (standard), cooling pump, heat-exchanger
Options and accesories Sunroof, SER drive interface (variable speed), HMI, blocked charge protection,…

 For dual motor (dual pinion) FlexStarter applications, ask about thefeatures of our Flex Duo starters.