EX-501 RGPV B.Tech
Electrical Machine-II (EM)
Previous year papers and the official syllabus are free to read, no account needed.
Previous Year Papers
6 papers, latest Dec 2025
- EX-501 paper, Dec 2025
- EX-501 paper, Jun 2025
- EX-501 paper, Dec 2024
- EX-501 paper, May 2024
- EX-501 paper, Nov 2023
- EX-501 paper, May 2023
Syllabus, notes and important questions for EX-501
Syllabus units
Topics as the official RGPV syllabus lists them.
Unit 1 D.C. Machine-I 10 topics
- Basic construction of DC machines
- Types of DC machines and method of excitation
- Lap and wave windings
- EMF equation
- Armature reaction and methods of limiting armature reaction
- Commutation process and methods for improving commutation
- Basic performance of DC generators and their performance characteristics
- Metadyne and Amplidyne
- Permanent magnet DC motors
- Brushless dc motors
Unit 2 D.C. Machine-II 8 topics
- Basic operation of DC motors
- Torque equation
- Operating characteristics of DC motors
- Starting of DC motors – 2 point, 3 point and 4 point starters
- Speed control of DC motors
- Losses and efficiency of DC machines
- Testing of DC machines, direct testing, Swinburne’s test and Hopkinson’s test
- Application of DC machines
Unit 3 Synchronous Machine-I 11 topics
- Construction
- Types of prime movers
- Excitation system including brushless excitation
- Polyphase distributive winding, integral slot and fractional slot windings
- EMF equation
- Generation of harmonics and their elimination
- Armature reaction
- Synchronous reactance and impedance
- Equivalent circuit of alternator
- Relation between generated voltage and terminal voltage
- Voltage regulation of alternators using synchronous impedance, mmf, zpf and new A.S.A method
Unit 4 Synchronous Machine-II 11 topics
- Salient pole machines
- Two reaction theory equivalent circuit model and phasor diagram
- Determination of Xd and Xq by slip test
- SCR and its significance
- Regulation of salient pole alternator
- Power angle equation and characteristics
- Synchronizing of alternator with infinite busbar
- Parallel operation and load sharing
- Synchronizing current, synchronizing power and synchronising torque coefficient
- Synchro scopes and phase sequence indicator
- Effect of varying excitation and mechanical torque
Unit 5 Synchronous machine-III 16 topics
- Synchronous motor operation, starting and stopping of synchronous motor
- Pull in torque
- Motor under load power and torque
- Reluctance torque
- Effect of excitation
- Effect of armature reaction
- Power factor adjustment, V curves, inverted V curves
- Synchronous motors as power factor correcting device
- Super synchronous and sub synchronous motors
- Hunting and damper winding efficiency and losses
- Analysis of short circuit oscillogram
- Determination of various transient, sub transient and steady reactances and time constants
- Expression of transient and sub transient reactances in terms of self and mutual inductances of various winding
- Short circuit current, equivalent circuit
- Single phase synchronous motors – hysteresis motor, reluctance motor
- Repulsion motor, stepper motor, switched reluctance
Exam insights
Counted from 6 past EX-501 papers.
Marks asked per paper, by unit
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Unit 1 D.C. Machine-I 18 marks
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Unit 2 D.C. Machine-II 27 marks
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Unit 3 Synchronous Machine-I 21 marks
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Unit 4 Synchronous Machine-II 20 marks
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Unit 5 Synchronous machine-III 21 marks
Average marks of the questions from each unit in one paper. You answer only some of them, so the total is more than the paper’s maximum.
Asked again and again
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Explain hunting phenomenon in synchronous machines/alternators/motors, its causes, and role of damper winding / damping methods to reduce it
Asked 5 times: 2026, 2025, 2023, 2019
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Determine how two alternators running in parallel share a given total kW load from their kW ratings and speed regulation from full load to no load.
Asked 4 times: 2025, 2024, 2023, 2020
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Explain / describe Swinburne's test with circuit diagram and how efficiency of a DC machine is determined from it
Asked 4 times: 2026, 2025, 2023, 2020