Permanent Magnet Synchronous Motor (PMSM)

Permanent Magnet Synchronous Motor (PMSM)

Torque motors are generally PMSM motors that can be fitted with a closed loop control mechanism, like conventional servomotors. But the concept and shape of the high torque servo motor is different. A torque motor is often round with a hole in it, a toroid shaped (like a donut). Because of this shape it has a large diameter and short axis. Thanks to this shape, the high torque servo motor generates a lot of torque. A conventional servomotor on the other hand, can reach higher RPM

Direct drive Permanent Magnet Synchronous Motor

Conventional motors generates far less torque than torque motors. To reach the desired speed to torque ratio, conventional servomotors are often fitted with a gearbox. But this gearing does reduce efficiency and accuracy. The load of the high torque servo motor is directly driven without the use of a gearbox or transmission. The direct drive technology increases the number of moving parts in the high torque servo motor. Because of this, the operational lifetime and efficiency of the motor and thereby the application are increased. Also, the peak point energy efficiency of high torque servo motors is much higher. 

We use innovative winding configurations combined with optimized permanent magnet technology, to maximize the torque of our torque motors. To guarantee smooth rotation with low torque ripple, a 3-phase sinusoidal current amplifier can be used. The motor is suitable for servo control applications thanks to the low cogging design. Other advantages of the high torque pm motors are:

  • High dynamics
  • High torque density
  • High efficiency
  • Optimal speed control
  • High reliability and lifetime
  • Low maintenance
  • Quiet operation

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PM Motor Specifications (standard range)

Our standard frameless PMSM torque motors, the MI-F series, are available in three outer diameters: 110, 250 and 485 mm (~4.3, 9.8, and 191 inch, respectively). Furthermore, each series is available in standard motor heights off 25 mm, 50 mm and 75 mm (~1, 2, and 3 inch). The range of continuous torque is covered between 4Nm and 796Nm and peak torque between 14Nm and 1143Nm. The MI-F series are designed for a wide RPM range.

Size (outer diameters):

110, 250 and 485mm


From 25 to 75mm

Continuous torque:

Between 4Nm and 796Nm

Peak torque:

Between 14Nm and 1143Nm

Lamination stack:

25, 50 and 75

Total mass:

From 1,52 to 52,37 kg / From 3.35 lbs to 115.46 lbs


Various winding designs possible

Cooling options:

Water or air


Sensored or sensorless control is possible

Servo control:

Suitable for servo control applications



Speed (RPM):

Wide RPM range


Automotive, food, non-food, industrial fans, industrial equipment, energy technology, machine tools, robotics & semicon, conveyor belts.

Custom motors

If our standard torque motor series are not adequate for your application, it is also possible to develop a custom motor. We have successfully built numerous customized torque motors for different application. We can customize motors in a variety of ways. Just tell us your needs and we will reply to you as soon as possible with an offer.

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High Torque PM Motors by Magnetic Innovations