SOLUTION

Torque motor

A torque motor can be thought of as being a linear motor that is folded to make a cylinder and whose ends are connected to each other. It is similar to a rotary synchronous motor with a very high number of pole pairs and has a large diameter.

The windings in the stator are arranged offset by 120° per pole division to each other and fed with a three-phase AC current. The stator current creates a high-pole rotating field that rotates slowly. The rotor follows accordingly. Due to its large diameter, the motor has an accordingly high torque.

Torque motors are available as built-in or complete motors. In the case of built-in motors, the motors do not have their own bearings. These motors must, therefore, be fitted on a machine shaft that has its own bearings. The stator and the rotor are supplied as separate components. As with linear motors, assembly requires special knowledge and skills.

Due to their large diameter, torque motors have a hollow shaft. This simplifies their integration into the driven machine. Torque motors are available in both air-cooled and water-cooled versions.

In many cases, the position encoder must be mounted externally. The connection to the motor shaft can be made, for example, using a toothed drive belt. The position encoder must be in line with the magnetic poles of the rotor.

Torque motors can deliver torques from 100 Nm up to approximately 5 kNm and have speeds ranging from 10 rpm to 300 rpm.