Question

A balanced delta-connected load of (2+j3) Ω per phase is connected to a balanced three-phase 440V supply. The phase current is 10A. Find the total active power.

(a) 7.26W

(b) 726W

(c) 7260W

(d) 72.6W

The question was posed to me in a national level competition.

My doubt stems from Voltage, Current and Power in a Delta Connected System in section Polyphase Circuits of Network Theory

Answer 1

Right option is (c) 7260W

To explain I would say: ZPh = √(2^2+3^2) = 3.6∠56.3⁰Ω. cosφ = RPh/ZPh = 2/3.6 = 0.55. IL = √3× IPh = 17.32A. Active power = √3 VLILcosφ = √3×440×17.32×0.55= 7259.78W.