Solved Problems

Electrical Machines

Theory tells you which equation to write. Only problems tell you whether you can write it. Forty-six problem sets that follow the textbook part for part — every solution worked line by line, every set closing with practice problems, challenge problems and a self-test.

Prof. Mithun Mondal GATE · ESE · University Exams Free & Open Access
6Parts
46Problem Sets
92Chapters Mapped
Welcome

A problem book, not a worked-answer list

Electrical machines are not learned by reading. They are learned by sitting in front of a nameplate you have never seen before, deciding which model applies, choosing a per-phase or per-unit basis, and grinding out the arithmetic until a number appears — and then asking whether a machine of that rating could possibly behave that way. This companion to the Electrical Machines textbook exists to give you that practice several hundred times over.

Every problem here is solved in full. Not a final answer with the middle omitted, but the actual sequence of decisions: which equivalent circuit is being used and why, whether a quantity has been referred to the stator or the rotor, where the sign of a regulation came from, and how the result was checked against the machine's rating. Where a step commonly goes wrong — a line-to-phase conversion dropped, a slip used where s-referred resistance was meant, an efficiency quoted from output over input when the losses were measured separately — the solution says so.

The forty-six sets below cover all six parts of the textbook, from the reluctance of a gapped iron core to the torque ripple of a switched reluctance drive. The parts mirror the book exactly, so a set can always be read against the chapter that derives its method.

How each set is built. A short strategy recap fixes the method in three or four lines. Then the solved problems, in rising difficulty, each with its circuit or characteristic drawn to scale. Then practice problems with answers you can check but solutions you must produce yourself, a small number of challenge problems that combine two or more machines, a set of multiple-choice questions of the type that appear in competitive examinations, and a closing list of the mistakes that cost marks in this topic.
Core — builds the method Exam level — GATE / ESE / university Challenge — combines machines

No sets match that filter. Clear the box to see all 46 again.

Part 1

Principles of Energy Conversion

Chapters 1–19 · Magnetic Circuits · Core Losses · Inductance · Energy and Coenergy

Magnetic Circuits — Chapters 2–4

Core Losses, Inductance and Energy — Chapters 5–19

Part 2

DC Machines

Chapters 20–39 · EMF Equation · Windings · Characteristics · Speed Control · Efficiency and Testing

Generators — Chapters 20–33

Motors, Efficiency and Testing — Chapters 34–39

Part 3

Transformers

Chapters 40–56 · Phasor Analysis · Equivalent Circuit · Testing · Regulation · Efficiency · Three-Phase

Single-Phase Transformers — Chapters 40–45

Testing and Performance — Chapters 46–51

Three-Phase and Special Transformers — Chapters 52–56

Part 4

Induction Machines

Chapters 57–70 · Slip · Torque · Power Flow · Equivalent Circuit · Testing · Circle Diagram · Control

Principles and Performance — Chapters 57–64

Testing and Control — Chapters 65–70

Part 6

Single-Phase and Special Machines

Chapters 82–92 · Double-Revolving Field · Equivalent Circuit · Capacitor Sizing · Special Machines

Single-Phase Induction Motors — Chapters 82–86

Special Machines — Chapters 87–92

Start Here
Begin with Set 1 — Magnetic Circuit Fundamentals

Most marks lost in machines are lost before any machine appears: a reluctance added in parallel when the flux path was in series, a relative permeability left out of the denominator, an MMF drop in iron neglected when the core was already near saturation. The first set drills exactly those habits on circuits simple enough that the arithmetic never hides the reasoning. Work it through even if it looks beneath you — the forty-five sets that follow assume every one of these reflexes. Open Set 1 →

Reading the theory alongside. Each problem set names the textbook chapters it belongs to. If a solution uses a result you have not met, open the corresponding chapter of Electrical Machines — the derivation will be there in full.