Are these Electrical Machines handwritten notes free?

Yes. Fill in the short form on this page and the PDF downloads right away. There is no fee for the notes.

Are these official university notes?

No. These are original Uncodemy revision notes for Electrical Machines. They are not issued or approved by AKTU or any other university, and they are not past papers.

Which syllabus do they follow?

They follow the common B.Tech syllabus for Electrical Machines used by most Indian universities, including AKTU and colleges on the AICTE model curriculum. Unit order and depth differ, so match the notes with your own university syllabus.

Do the notes cover both Machines I and Machines II?

They cover DC machines, transformers, induction machines and synchronous machines in one PDF. Universities split these topics differently between the two papers, so check your own syllabus.

Are transformer numericals included?

Yes. There is a solved example on full-load and maximum efficiency, and the unit covers OC and SC tests and regulation.

Electrical Machines Handwritten Notes PDF

Key takeaways

Nine units covering DC machines, transformers, induction machines and synchronous machines.
The DC generator EMF equation and DC motor speed change are worked through with numbers.
Transformer tests, regulation and maximum efficiency are solved for a 20 kVA unit.
Induction motor power flow, torque-slip, starting methods, alternator regulation and V-curves are covered.
Original Uncodemy revision notes, not official university notes. Check your own syllabus.

About these handwritten notes

These Electrical Machines notes are original Uncodemy revision notes, written in a clean handwritten style so they are quick to read before an exam. They follow the common B.Tech syllabus for Electrical Machines (B.Tech EE and EEE, and GATE EE basics). They are not official university notes and not copied from any textbook or past paper.

Topic order, unit numbers and depth vary between universities, so first place each unit below against your own university syllabus. If your syllabus has a topic that is missing here, add it in the margin from your class notes or textbook. Use these notes for revision after you have studied the topic once in class, not as your only study material. They are short on purpose: the aim is to help you recall the main ideas, formulas and diagrams quickly, so that your exam time goes into writing good answers.

What's inside the Electrical Machines notes

The notes follow the usual order of machines courses, from DC machines to synchronous machines. Each unit has equivalent circuits, phasor sketches, formula boxes and solved numericals.

Unit 1: Basics of Energy Conversion. Electromechanical energy conversion, induced EMF and force on a conductor.
Unit 2: DC Generators. Construction, EMF equation, types, armature reaction and commutation.
Unit 3: DC Motors. Back EMF, torque, speed control, starters, losses, efficiency and tests such as Swinburne's test.
Unit 4: Single-Phase Transformer. EMF equation, equivalent circuit, OC and SC tests, voltage regulation, efficiency and all-day efficiency.
Unit 5: Three-Phase Transformers and Autotransformer. Connections, parallel operation conditions and the autotransformer.
Unit 6: Three-Phase Induction Motor. Rotating field, slip, rotor frequency, power flow, the torque-slip curve and starting methods.
Unit 7: Single-Phase Induction Motors. Why they are not self-starting, double revolving field theory and split-phase and capacitor motors.
Unit 8: Synchronous Generator (Alternator). EMF equation, armature reaction, voltage regulation methods and parallel operation.
Unit 9: Synchronous Motor. Working, V-curves, the synchronous condenser and hunting.

The last page of the PDF lists the most asked practice questions for the whole subject, so you can test yourself after finishing all the units.

Formulas and solved examples in the PDF

Formula boxes cover E = PΦZN/(60A), back EMF and speed, the transformer EMF equation, regulation, maximum efficiency at x = √(Pi/Pcu), slip, rotor frequency and the induction motor power split. Solved examples include a 4-pole lap-wound generator, a shunt motor speed change under load, full-load and maximum efficiency of a 20 kVA transformer, and the power flow of a 4-pole motor at 4% slip.

How to revise Electrical Machines with handwritten notes

Handwritten-style notes work best when you read actively. Keep a pen and a rough notebook beside you, cover the formula or diagram, and try to write it yourself before you look.

Draw the equivalent circuit of each machine once from memory. Most derivations start from it.
Keep the induction motor power flow as a single chain: input, stator loss, air-gap power, rotor copper loss (s x Pg), mechanical power.
For transformers, solve one OC and SC test problem that ends in regulation and efficiency. It covers a whole long question.
Write one line on why each starter or starting method is needed, such as star-delta reducing starting current to one third.

In the last week, read only the formula boxes and exam tips, and solve one numerical or long question per unit from memory. If you study with friends, ask each other to explain one diagram or derivation aloud. Explaining a topic is the fastest way to find the gaps in it.

A short revision plan

If your exam is about a week away, this plan covers every unit in the PDF once and leaves time for practice. Stretch it over two weeks if you are starting from scratch.

Day 1: Basics of Energy Conversion, DC Generators.
Day 2: DC Motors, Single-Phase Transformer.
Day 3: Three-Phase Transformers and Autotransformer, Three-Phase Induction Motor.
Day 4: Single-Phase Induction Motors, Synchronous Generator (Alternator).
Day 5: Synchronous Motor.
Day 6: Solve the practice questions in the exam focus section below, one per unit, without the notes.
Day 7: Read only the formula boxes and exam tips, redo the numericals you got wrong, and sleep early.

Common mistakes to avoid

Using A = 2 for a lap winding. For lap winding A = P; for wave winding A = 2.
Starting a DC series motor at no load. Flux is very small, so the speed can rise to a dangerous value.
Using full-load copper loss at part load without scaling it by the square of the load fraction.
Taking rotor copper loss as s times the input power instead of s times the air-gap power.

How Electrical Machines links to other subjects

Electrical Machines builds on Basic Electrical Engineering and magnetic circuits. It is the base for Electric Drives, Power Systems and Switchgear and Protection, which all assume you know how these machines behave.

Exam focus: high-weightage topics

University papers usually give the most weight to DC machine EMF and speed control, transformer equivalent circuit, tests, regulation and efficiency, induction motor torque and power flow, and alternator regulation. GATE EE numericals come mostly from transformer efficiency, induction motor slip and power flow, and DC motor speed.

Typical long and numerical questions to practise:

Derive the EMF equation of a DC generator and solve a numerical.
Compare speed control methods of DC shunt motors and explain why a starter is needed.
Explain OC and SC tests and find regulation and efficiency from test data.
State the condition for maximum efficiency of a transformer and explain all-day efficiency.
Derive the torque equation of an induction motor and the condition for maximum torque.
Explain the synchronous impedance method of finding alternator regulation, and V-curves of a synchronous motor.

When you write a long answer, start with a one-line definition, draw the diagram or circuit, write the derivation in clear steps and end with the final result and its unit. For numericals, write the formula first, then substitute, so you can still earn step marks if the arithmetic slips.

These are practice questions based on common syllabus topics. They are not verified past papers, and we do not claim any question will appear in your exam. For real previous papers, use your university's official archive.

Who these notes are for

These notes are for B.Tech EE and EEE students preparing for their Electrical Machines I and II semester exams, and for students revising GATE EE basics such as transformer efficiency and regulation, induction motor slip and power flow, and DC motor speed. They are also useful before PSU and core electrical interviews, which often start with machine questions.

Download Electrical Machines Handwritten Notes PDF