In hysteresis motor, hysteresis torque remains practically _______.

The correct answer is option 3):(constant)

Concept:

• A hysteresis motor is a synchronous motor
• It has a cylindrical rotor and works on hysteresis losses induced in the rotor of hardened steel with high retentivity. 
• It is a single-phase motor
• It has a rotor is made of ferromagnetic material with non-magnetic support over the shaft.
• A hysteresis motor is constructed of five main components Stator, Single-phase stator winding, Rotor, Shaft, Shading coil
• The stator of the hysteresis motor has a main winding along with an auxiliary or starting winding. When the stator winding is fed from a single-phase supply, it produces a synchronously revolving magnetic field.
• In the hysteresis motor, hysteresis torque remains practically constant
• The revolving magnetic field is accomplished by using a permanent split capacitor type construction of the motor. As a result, both the starting and the main windings of the motor remain connected in the motor circuit during running as well as at starting.
• The value of the capacitor is so adjusted that it results in a flux revolving at synchronous speed. The rotor of the hysteresis motor consists of a smooth cylinder of magnetically hard steel, without winding or rotor teeth.
• In the hysteresis motor, hysteresis torque remains practically constant
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