Liquid cooled motor solutions

Liquid-cooled electrical machines offer a great option to air -cooled if cooling liquid is already available on the application site.  A liquid-cooled Randax® electrical machine can reach efficiency up to 50% higher than a corresponding air-cooled machine. This makes liquid-cooled Randax® electrical machines extremely compact and efficient.

Benefits of liquid cooling are high output-to-size ratio, dirt and dust cannot enter the closed cooling circuit and machine is not sensitive to surrounding air temperatures. Randax® motor technology enables the efficient cooling inside the entire machine frame and customized materials and coolants according to application and customer needs.

The liquid-cooled electrical motors can be tailored for example to pump liquids, to be used as a drive motor for vehicles and construction machinery or in demanding process industry applications.

Randax® has developed new series of liquid-cooled electrical motors for power range of 45 – 500 kW with following specifications.

Technical specifications:



Nominal power

45 kW 60 kW 125 kW 200 kW 300 kW 500 kW

Nominal voltage

400 VAC 400 VAC 400 VAC 400 VAC 400 VAC 400 VAC

Rotation speed

1 000 RPM 1 000 RPM 2 000 RPM 2 000 RPM 1 000 RPM 1 000 RPM

Nominal torque

429 Nm 573 Nm 600 Nm 955 Nm 2 865 Nm 4 775 Nm


> 96% > 96% > 96% > 96% > 96% > 96%

Diameter, frame*

490 mm 490 mm 490 mm 490 mm 680 mm 680 mm
Diameter, end flange * 517 mm 517 mm 517 mm 517 mm 700 mm 700 mm


390 mm 390 mm 390 mm 490 mm 750 mm 900 mm

Frame material

Steel Steel Steel Steel Steel Steel

* Diameter, length and weight may vary depending on application where motor is integrated

Slow speed, High torque motor solutions with double cell frame motor

For slow speed (e.g.100 – 900 rpm) motor application and motors size of 500-3 000 kW Randax has an optional double cell frame motor design. This motor design has both cooling’s integrated together, water cooling jacket around the stator and internal air ventilation with air-liquid heat exchanger.

Principal drawing of double frame and double cooling motor / generator

More information about double cell frame motor design, please contact Randax sales!