Question

The core of a transformer is laminated to reduce

• A. hysteresis loss
• B. eddy current loss
• C. copper loss
• D. magnetic flux leakage
• E. humming noise

Hint:

Remember the "Three H's" of transformer losses:

• \textbf{Heat} (Copper loss) - Use thick wires.
• \textbf{Hysteresis} - Use Soft Iron.
• \textbf{High Eddy Currents} - Use Laminations.

Answer 1

The Correct Option is B

Concept:
Physics - Transformer Losses and Design.
Step 1: Understand Eddy Currents.
When the magnetic flux through a solid metallic core changes, induced currents are produced in the body of the core. These are known as eddy currents. They circulate in closed paths and generate heat due to the resistance of the metal.
Step 2: Identify the effect of lamination.
Lamination involves building the core from thin sheets of soft iron, each insulated from the other by a thin layer of varnish.
Step 3: Analyze the resistance.
By breaking the solid core into thin layers, the paths for eddy currents are restricted to very small loops. This significantly increases the effective electrical resistance of the path, thereby reducing the magnitude of the current.
Step 4: Conclusion.
Since $P = I^2 R$, reducing the current $I$ leads to a massive reduction in energy loss as heat. Thus, lamination is used to minimize eddy current loss.