Transformer Core — Function and Why It Is Laminated

1. Function of the Transformer Core

The core provides a low-reluctance path that channels magnetic flux from the primary winding to the secondary winding, improving magnetic coupling and transformer efficiency.

• Concentrates and guides magnetic flux between windings.
• Reduces flux leakage and increases induced emf in the secondary.
• Lowers magnetising current by offering an easy path for flux (low reluctance).
• Supports the windings mechanically.

2. Why the Core Is Laminated using silicon steel

Lamination reduces eddy currents that are induced inside the core by alternating flux. Without lamination, large circulating currents would cause heating and energy loss.

How lamination helps

• The core is made from thin insulated sheets stacked together, which interrupts the paths available for eddy currents.
• Smaller eddy currents → less heating → higher efficiency.

Why silicon steel?

• Silicon steel has high magnetic permeability, so it easily supports magnetic flux with low magnetising current.
• It has lower hysteresis loss compared to plain iron, so less energy is lost when the magnetic field reverses each AC cycle.
• It can be manufactured into thin laminations and coated for insulation between sheets.