Torque motor

A torque motor is a specialized form of electric motor which can operate indefinitely while stalled, that is, with the rotor blocked from turning, without incurring damage. In this mode of operation, the motor will apply a steady torque to the load (hence the name). A torque motor that cannot perform a complete rotation is known as a limited angle torque motor.Torque motors are DC motors. Torque motors sometimes avoid commutators and brushes called brushless dc motors, elimination of these parts allow dc motors or torque motors to work at higher speed A torque motor is a specialized form of electric motor which can operate indefinitely while stalled, that is, with the rotor blocked from turning, without incurring damage. In this mode of operation, the motor will apply a steady torque to the load (hence the name). A torque motor that cannot perform a complete rotation is known as a limited angle torque motor.Torque motors are DC motors. Torque motors sometimes avoid commutators and brushes called brushless dc motors, elimination of these parts allow dc motors or torque motors to work at higher speed Torque motors are normally induction motors of toroidal construction. Their main differences from other similar motors are their wide diameters, to allow for high levels of torque, and their thermal performance, to allow their continuous operation while drawing high current in a stalled state. An analogous device, working linearly rather than by rotation, is described as a 'force motor'. These are widely used for refrigeration compressors and ultra-quiet air compressors, where the force motor produces simple harmonic motion in conjunction with a restoring spring. A common application of a torque motor would be the supply- and take-up reel motors in a tape drive. In this application, driven from a low voltage, the characteristics of these motors allow a relatively constant light tension to be applied to the tape whether or not the capstan is feeding tape past the tape heads. Driven from a higher voltage, (and so delivering a higher torque), the torque motors can also achieve fast-forward and rewind operation without requiring any additional mechanics such as gears or clutches.