Question

A 1000/5 A, 50 Hz correct transformer has a secondary burden comprising a non-inductance of 1.6Ω. The flux in the core at full load is?

(a) 160 μWb

(b) 180 μWb

(c) 200 μWb

(d) 150 μWb

The question was asked in an online quiz.

My doubt is from Advanced Problems on C.T. and P.T. in portion Extension of Instrument Ranges of Electrical Measurements

Answer 1

The correct answer is (b) 180 μWb

The explanation: Turn ratio = 1000/5 = 200

NP = 1

So, NS = 200

Secondary impedance = 1.6Ω

Secondary induced voltage, ES = 5 × 1.6 = 8 V

∴ ES = 4.44 f N ∅

So,  ∅ = \(\frac{E_S}{4.44 \,f \,N} = \frac{8}{4.44 \,f \,N}\) = 180 μWb.