Question

What is the hysteresis loss in soft magnetic material?

Answer 1

Hysteresis loss in soft magnetic materials refers to the energy lost as heat when the material is magnetized and demagnetized in a cyclic manner.

When a magnetic field is applied to a soft magnetic material, the magnetic domains inside the material align with the field. As the field strength increases, the magnetization of the material increases. When the field is reduced and reversed, the domains attempt to realign in the opposite direction, but due to internal friction and resistance to change, not all domains switch perfectly. This process creates energy loss.

The energy lost during each cycle of magnetization and demagnetization is known as hysteresis loss. This loss depends on factors such as:

1. The material's properties: Soft magnetic materials like iron or silicon steel tend to have lower hysteresis losses compared to harder magnetic materials.
   

1. The frequency of the applied magnetic field: Higher frequencies lead to more rapid changes in magnetization, which increases hysteresis loss.
   

1. The area inside the hysteresis loop: The larger the loop, the greater the energy loss. The loop is a graphical representation of the relationship between the magnetic field strength and the magnetization of the material.
   

Hysteresis loss is undesirable in many electrical devices like transformers and electric motors, as it contributes to heat generation and reduces the overall efficiency of the device. The key to reducing hysteresis loss is choosing materials with low coercivity and optimizing the design to minimize the energy lost in each cycle.