GATE EE concept:efficiency PYQs & Answers

Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.

Questions 1–4 of 4. Imported answers require independent review unless marked reviewed.

Topic practice 4 questionsPage 1 of 1

A three phase, 50 Hz, 6 pole induction motor runs at 960 rpm. The stator copper loss, core loss, and the rotational loss of the motor can be neglected. The percentage efficiency of the motor is

Your answerChoose one option.

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A 5 kW, 220 V DC shunt motor has 0.5

armature resistance including brushes. The motor draws a no-load current of 3 A. The field current is constant at 1 A. Assuming that the core and rotational losses are constant and independent of the load, the current (in amperes) drawn by the motor while delivering the rated load, for the best possible efficiency, is ________ (rounded off to 2 decimal places).

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The power input to a 500 V, 50 Hz, 6-pole, 3-phase induction motor running at 975 RPM is 40 kW. The total stator losses are 1 kW. If the total friction and windage losses are 2.025 kW, then the efficiency is ________%.

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A 3-phase 900 kVA,

(

/Y), 50 Hz transformer has primary (high voltage side) resistance per phase of 0.3

and secondary (low voltage side) resistance per phase of 0.02

. Iron loss of the transformer is 10 kW. The full load % efficiency of the transformer operated at unity power factor is ________ (up to 2 decimal places).

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GATE EE concept:efficiency PYQs

How to practice concept:efficiency

Question 17

Question 55

Question 18

Question 51