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 Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

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.