Question

What is hysteresis loss in transformer class 12 physics?

Answer 1

Hysteresis loss in a transformer occurs due to the repeated magnetization and demagnetization of the iron core when AC supply is given. As the magnetic field changes direction, the core material resists these changes, leading to energy loss in the form of heat.

Explanation:

1. The transformer core is made of ferromagnetic material, which retains some magnetism even after the external magnetic field is removed.
   

1. When the alternating current reverses, the core undergoes a cycle of magnetization and demagnetization.
   

1. This continuous cycle results in energy loss, as some energy is used to realign the magnetic domains inside the core.
   

1. The lost energy is converted into heat, reducing the efficiency of the transformer.
   

Formula for Hysteresis Loss:

\[
P_h = \eta B_m^{1.6} f V
\]
Where:

1. \( P_h \) = Hysteresis loss (Watts)
   

1. \( \eta \) = Steinmetz constant (depends on the core material)
   

1. \( B_m \) = Maximum magnetic flux density
   

1. \( f \) = Frequency of AC supply
   

1. \( V \) = Volume of the core
   

How to Reduce Hysteresis Loss:

1. Using materials with low hysteresis loss, such as silicon steel.
   

1. Using laminated cores to reduce energy loss due to eddy currents.
   

Hysteresis loss is a major factor affecting transformer efficiency, along with eddy current loss.