Question

Explain the energy losses in the transformer. How are they minimized?

Answer 1

Hint: A transformer is an electrical apparatus which is used to convert an alternating current from one voltage to another. It can be designed to step up or step down voltages based on the number of turns in the coil in primary and the secondary coil. It works on the magnetic induction principle.

Complete step by step solution:
A transformer is designed to convert alternating current into another voltage very efficiently. But there are small energy losses that do occur in them. The four main causes cause of energy loss in transformer are as following:

1. Resistance of windings – The wire used in the winding of the coil of the transformer contributes to heat loss due to electric heating.
As per Joule’s law of heating,
$P={{i}^{2}}R$
Where, $P$ is the rate of heat generated in the wire of resistance $R$ when $i$ is the electric current in the wire.

2. Flux leakage– Due to error in the design of the core of the secondary coil, all the magnetic flux produced in the primary coil may not be linked to the secondary coil. That is the reason for the flux leakage.

3. Eddy currents – When the magnetic field in primary coil changes then it induces currents in the secondary coil and also currents in the iron core itself. These currents flow in little circles in the iron core and are called eddy currents. The eddy currents cause heat loss.

4. Hysteresis – The magnetization of the core is repeatedly reversed by the alternating magnetic field. The repeating core magnetization process expends energy and this energy appears as heat.

Methods to reduce the energy loss in transformer:

1. Use of low resistance wire for the winding of the coil.

2. Heat loss due to eddy current can be reduced by the lamination of the iron core.

3. The heat generated can be kept to a minimum by using a magnetic material which has a low hysteresis loss. Hence, soft iron is often chosen for the core material because the magnetic domains within it changes rapidly with low energy loss.

Note: 1. Transformer converts an alternative current into another voltage.
2. There are two types of transformer one is step up transformer and another is step down transformer.