Explain hysteresis losses.

Question

What will be an ideal response?

Answer 1

In alternating current, the direction of current is constantly changing. This means that the lines of force of the magnetic field are also changing direction repeatedly. In other words, millions of molecules reverse direction in the process of magnetizing, demagnetizing, and remagnetizing the structure of any iron core or other metallic material adjacent to the conductors of an ac circuit.

As these molecules reverse their direction with each change of magnetization, molecular friction results. Power is required to overcome this molecular friction. This loss occurs as heat in the metallic structure and is known as hysteresis loss. The ac circuit adjacent to the metallic material must supply the power in watts to overcome this hysteresis loss. All ac generators, ac motors, transformers, and other ac equipment experience hysteresis loss. To reduce this loss, special steels are used for the core structure. For example, silicon steel may be used because it has a relatively low molecular friction loss.