Question

Discuss four main causes of energy loss in a real transformer.

Hint:

To minimize energy loss in transformers, high-quality core materials with low hysteresis, laminated cores to reduce eddy currents, and low-resistance wires are used.

Answer 1

Step 1: Hysteresis Loss:
Hysteresis loss occurs due to the magnetization and demagnetization of the iron core. Every time the magnetic flux changes direction, energy is lost due to the lag between the magnetic field and the magnetization of the core material. This loss is proportional to the frequency of the AC supply and the volume of the core.
Step 2: Eddy Current Loss:
Eddy currents are circulating currents induced in the core of the transformer due to the alternating magnetic flux. These currents lead to energy dissipation in the form of heat. To reduce eddy current loss, the core is made of laminated sheets of iron with insulation between them.
Step 3: Resistive (Copper) Loss:
Resistive loss occurs in the windings of the transformer due to the resistance of the copper wire. As current flows through the windings, heat is generated due to the resistance of the wire. This loss increases with the square of the current and is a function of the wire's resistance.
Step 4: Leakage Flux Loss: Not all of the magnetic flux generated by the primary coil links with the secondary coil. Some of the flux leaks out of the core and does not contribute to the induction of voltage in the secondary coil. This leakage flux leads to inefficiencies and losses in the transformer. Conclusion:
The main causes of energy loss in a real transformer are:
1. Hysteresis loss due to magnetization of the core material.
2. Eddy current loss due to circulating currents in the core.
3. Resistive (copper) loss in the windings.
4. Leakage flux loss due to non-ideal magnetic coupling between primary and secondary coils.