Question.

The no-load current of a transformer is 5.0 Amps, power factor 0.25, when supplied at

235 V, 50 Hz. Turns on the primary winding is 200.

Calculate

(i) The maximum value of flux in the core,

(ii) The core loss.

V1(Eo) = 4.44Φm.f.N volts

Φ = Eo / 4.44 x f x N = 235 / 4.44 x 50 x 200

Φ = 5.3 x 10(-3)Wb

The core loss = input power at no load

Vcore = VIcos Φ watt

= 235 x 5 x 0.25

Core loss = 29.4 watt