The correct answer is D. It accelerates from rest to full-speed almost instantaneously.
A hysteresis motor is a type of electric motor that uses the principle of hysteresis to generate torque. The rotor of a hysteresis motor is made of a ferromagnetic material, such as iron or steel. The stator of the motor is made of a non-magnetic material, such as copper or aluminum. When the motor is turned on, an alternating current is applied to the stator windings. This creates a magnetic field that rotates around the stator. The rotor aligns itself with this magnetic field, and as it does so, it creates its own magnetic field. The interaction of these two magnetic fields creates torque, which causes the rotor to turn.
Hysteresis motors are characterized by their high starting torque and their quiet operation. They are also relatively insensitive to fluctuations in supply voltage. However, they do have one major drawback: they accelerate slowly from rest. This is because the rotor must first align itself with the stator magnetic field before it can start to turn. This alignment process takes some time, which is why hysteresis motors are not typically used in applications where rapid acceleration is required.
In conclusion, the correct answer to the question “Which of the following statements regarding hysteresis motor is in incorrect?” is D. It accelerates from rest to full-speed almost instantaneously.