Question

Why is the core of a transformer laminated?

Answer 1

Hint: In this question use the concept that a core of a transformer is conducting and produces eddy current so as to minimize these currents and to prevent losses transformers are laminated. This will help get the right answer.

Complete Step-by-Step solution:
The core is designed such that no current flows through it.
But the core is a conducting loop that experiences a changing magnetic field due to variation in the flux of the core of the transformer induced by some small amount of current called Eddy current.
As these currents interfere with the efficiency of the transformer while transferring energy from primary coil to secondary coil.
The eddy current causes energy to be lost in the form of heat (as the core heated due to these currents), so we have to minimize these currents.
So one of the very best and widely used methods is lamination of the core while laminating the core the eddy current loss is not completely eliminated but reduced to minimum value.
The equation for eddy current loss is given as:
\[{P_{{\mathbf{e}}\;}} = {\text{ }}{{\text{K}}_{\mathbf{e}}}\; \times {\text{ }}{{\text{B}}_{{\mathbf{max}}}}^{\mathbf{2}}\; \times {\text{ }}{{\text{f}}^{\mathbf{2}}} \times \;{\text{ }}{{\text{t}}^{{\mathbf{2}}\;}} \times {\text{ v}}\], where
Pe = eddy current loss (W)
Ke = eddy current constant
B = flux density (Wb/$m^2$)
f = frequency of magnetic reversals per second (Hz)
t = material thickness (m)
V = volume ($m^3$)
So doing laminations the thickness and volume of the core reduced so that eddy current loss also reduced.
Hence the core of the transformer is laminated so that eddy current loss can be minimized.

Note – A transformer is a passive electrical device that transfers electrical energy from one electrical circuit to another or multiple circuits. Transformers can also be used for isolation, where the voltage in equals the voltage out, with separate coils that are not electrically bonded to one another.