Question

If the 3-phase balanced source in the given figure delivers 1500 W at a leading power factor of 0.844, then the value of ZL is approximately __________

(a) 90∠32.44°

(b) 80∠32.44°

(c) 80∠-32.44°

(d) 90∠-32.44°

I got this question by my college director while I was bunking the class.

My question comes from Problems Involving Coupling Coefficient in portion Resonance & Magnetically Coupled Circuit of Network Theory

Answer 1

The correct choice is (d) 90∠-32.44°

For explanation I would say: 3VP IP cosθ = 1500

Or, 3\((\frac{V_L}{\sqrt{3}}) (\frac{V_L}{\sqrt{3} Z_L})\) cos θ = 1500

Or, ZL = \(\frac{V_L^2}{1500} = \frac{400^2 (0.844)}{1500}\) = 90 Ω

And θ = ∠-arc cos⁡(0.844)

= ∠-32.44°.