GATE EE 2026 Set 1 — Question 59
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.NAT+2 / -0MediumTorque-Speed & Max TorqueThree-Phase Induction MachinesElectrical MachinesStarting & Speed Control
Electrical Machines → Three-Phase Induction Machines → Starting & Speed Control
Last updated
Question
A balanced three-phase supply is given to a 30 kW, 4-pole, 400 V, 50 Hz, wound rotor induction motor with Y-connected stator and rotor windings. The motor is driving a constant torque load. With shorted sliprings, the machine runs at 1476 rpm.When an external non-inductive resistance of 0.27 per phase is connected in series in the rotor circuit, the steady-state speed drops to 1404 rpm.Neglecting rotational losses, the actual per phase rotor winding resistance is ____ (Round off to two decimal places)
Correct answer
0.09 to 0.09
Solution
Synchronous speed .Case 1 (shorted sliprings):
Slip .Case 2 (external resistance ):
Slip .For an induction motor driving a constant torque load, the torque is constant. Neglecting stator impedance and for small slips, . Thus:
Slip .Case 2 (external resistance ):
Slip .For an induction motor driving a constant torque load, the torque is constant. Neglecting stator impedance and for small slips, . Thus:
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE EE question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Three-Phase Induction Machines
2026 Set 1 Q17A 15 kVA, 1100 V/220 V, single-phase two-winding transformer is configured as a 1.32 kV/1.1 kV…2026 Set 1 Q20A certain application requires power at a frequency of , while the available grid…2026 Set 1 Q21Which one of the following options is correct regarding the typical double-squirrel-cage structure…2026 Set 1 Q22The figure shows the single-line diagram of a synchronous generator delivering …2026 Set 1 Q31A 220V/12V single-phase transformer is designed for use in India and rated 100 VA at 50 Hz. Later,…