Question

The resistance of copper motor winding at t=20°C is 3.42 Ω. After extended operation at full load, the motor windings measures 4.22 Ω. If the temperature coefficient is 0.0426, what is the rise in temperature? (a) 60°C (b) 45.2°C (c) 72.9°C (d) 10.16°C The question was posed to me by my school principal while I was bunking the class. I want to ask this question from Problems Involving Dot Conventions in division Resonance & Magnetically Coupled Circuit 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 (d) 10.16°C Explanation: Given that, R1 = 3.42 Ω T1 = 20° and α = 0.0426 R2 = 4.22 Ω Now, \frac{R_1}{1 + αT_1} = \frac{R_2}{1 + αT_2} Or, \frac{3.42}{1 + 0.0426 × 20} = \frac{4.22}{1 + 0.0426 T_2} ∴ Rise in temperature = T2 – T1 = 30.16 – 20 = 10.16°C.