The GATE Grind

GATE Electrical Circuits and Machines: Transformers and electrical machines – Previous Year Questions

12 GATE previous year questions on Transformers and electrical machines (Electrical Circuits and Machines, Instrumentation Engineering) with answers and explanations, from every paper.

  1. GATE 2021 IN Q22 (1 mark, Numerical answer) – A single-phase transformer has magnetizing inductance 250 mH and core-loss resistance 300 , referred to its primary. With a 230 V, 50 Hz sinusoidal…
  2. GATE 2021 IN Q37 (2 marks, Multiple choice) – A single-phase transformer has maximum efficiency 98%, core loss 80 W, equivalent winding resistance 0.5 referred to the primary, and rated primary…
  3. GATE 2021 IN Q38 (2 marks, Multiple choice) – A slip-ring induction motor is started by adding resistance to the rotor circuit. Compared with a shorted rotor, the benefit is .
  4. GATE 2022 IN Q29 (1 mark, Numerical answer) – A 440 V, 8 kW, 4-pole, 50 Hz, star-connected induction motor has a full load slip of 0.04. The rotor speed (in rpm) at full load is (round off to one…
  5. GATE 2023 IN Q35 (1 mark, Numerical answer) – The no-load steady-state output voltage of a DC shunt generator is 200 V when it is driven in the clockwise direction at its rated speed. If the same…
  6. GATE 2023 IN Q58 (2 marks, Numerical answer) – A single-phase transformer is short-circuit tested at 1 kHz with its secondary shorted. The wattmeter reads 8 W, primary current is 2 A, and primary…
  7. GATE 2024 IN Q61 (2 marks, Numerical answer) – A 50 kVA transformer has efficiency 95% at full load and unity power factor. Core loss is negligible. Its efficiency at 75% of full load and power…
  8. GATE 2024 IN Q62 (2 marks, Numerical answer) – A three-phase squirrel-cage induction motor has starting torque 100% of full-load torque and maximum torque 300% of full-load torque. Neglect stator…
  9. GATE 2025 IN Q46 (2 marks, Multiple choice) – A 2-pole, 50 Hz, 3-phase induction motor supplies power to a certain load at 2970 rpm. The torque-speed curve of this machine follows a linear…
  10. GATE 2025 IN Q60 (2 marks, Numerical answer) – The shown circuit is driven at 50 Hz by V s=25230 V. Both transformers are ideal. Average power in the 50 kΩ resistor is W (rounded to two decimal…
  11. GATE 2026 IN Q17 (1 mark, Multiple choice) – A single-phase step-down transformer has a high-voltage primary winding and a low-voltage secondary winding. The secondary winding is connected to a…
  12. GATE 2026 IN Q58 (2 marks, Numerical answer) – A single-phase transformer has a rating of 10 kVA, 50 Hz, 1100 V/220 V. In an open-circuit test with the high-voltage side open, the following are…