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 arises from the repeated magnetization and demagnetization of the transformer's iron core. Each reversal of the magnetic flux causes energy dissipation due to the lag between the magnetic field and the core material's magnetic state. This loss is directly proportional to both the AC supply frequency and the core's volume.
Step 2: Eddy Current Loss:
Eddy currents, which are induced circulating currents within the transformer core by the alternating magnetic flux, lead to energy loss as heat. To mitigate this, the core is constructed from thin, insulated iron laminations.
Step 3: Resistive (Copper) Loss:
Resistive losses occur in the transformer's windings due to the inherent resistance of the copper wire. When current flows through these windings, heat is generated. This loss is directly proportional to the square of the current and the wire's resistance.
Step 4: Leakage Flux Loss: Not all magnetic flux produced by the primary coil effectively links with the secondary coil. A portion of this flux "leaks" away from the core, failing to induce voltage in the secondary coil. This leakage flux contributes to transformer inefficiency and energy loss.
Conclusion:
The primary sources of energy loss in a practical transformer are:
1. Hysteresis loss: Resulting from the core material's magnetization cycle.
2. Eddy current loss: Caused by induced circulating currents within the core.
3. Resistive (copper) loss: Occurring in the windings due to their electrical resistance.
4. Leakage flux loss: Due to incomplete magnetic coupling between the primary and secondary coils.