Page 536 - Basic Electrical Engineering

Figure 6.4 Constructional details of a transformer. (a) Outside view of a transformer; (b) view of
core and windings

where, N is the number of turns of the winding, and ϕ is the flux produced.
EMF will also be induced in the core material when the material is being
subjected to an alternating magnetic field. Due to this induced EMF in the

core, a circulating current, called eddy current will flow across the core cross
section. If the core is laminated and the laminated sheets are varnished with

varnish insulation, the eddy current will get reduced, and hence there will be
reduced eddy current loss. To reduce the eddy current loss in the core it is,

therefore, made up of thin laminated silicon steel sheets.
Instead of iron, the core is made up of laminated silicon steel sheets. When

a certain percentage of silicon is added to steel, the hysteresis loss in the core
gets reduced. Hysteresis loss occurs due to orientation of the magnetic
dipoles of the magnetic material when the material is subjected to the

alternating magnetic field.