The document outlines an introductory course on electrical machines, detailing principles of energy conversion, electromagnetic induction, and the operation of various components such as DC generators, motors, and transformers. It covers fundamental electrical concepts, including electricity, electromotive force, and the history of electricity, alongside critical terminology related to magnetic circuits. Testing methods for transformers and their practical applications are also discussed.

1. Introduction Class

2. • MODULE 1 PRINCIPLES OF ENERGY CONVERSION
Faraday's law of electromagnetic induction -singly and doubly
excited magnetic field systems -EMF and torque production in
rotating machines.
• MODULE 2 DC GENERATORS
Construction – Windings – Principle of operation – Types –
Characteristics. Armature reaction and commutation - parallel
operation-Applications
• MODULE 3 DC MOTORS
Principle of operation – Types – Characteristics – Starting and
Speed control –Various testing- Applications
• MODULE 4 TRANSFORMERS
Construction – Principle of operation – Types – phasor diagram
of practical transformer on no load and load – Equivalent circuit –
Voltage regulation and efficiency- Auto transformer.-Applications
• MODULE 5 TRANSFORMER TESTING
Testing of transformers –Polarity, open circuit, short circuit and
Sumpner‟s test –Three phase transformers connections- Parallel
operation
Syllabus
19UEE303 - Electrical Machines – I 2

3. What Is Electricity?
• Form of energy involving the flow of
electrons
• All matter is made up of atoms
• Center called a nucleus
• Positively charged particles - protons
• Uncharged particles - neutrons
• Surrounded by negatively charged particles –
electrons
• Number of electrons = number of protons
19UEE303 - Electrical Machines – I 3

4. What is an Electromotive Force?
• Force that acts on the electrons to make them move
in a certain direction - voltage
• Work done on a unit electric charge
• Unit : volts (joules/ coulombs)
Electrical power - Rate at which energy is being
used or generated
• Unit: watts
Energy - rate at which work is being done
• Unit: joules (J) (watt-second)
Direct current (DC) - does not change direction
AC current - charges continually change direction
19UEE303 - Electrical Machines – I 4

5. What is Electric Current?
• Rate of flow of electrons in a conductor
• Unit : Ampere (coulombs per second)
19UEE303 - Electrical Machines – I 5

6. History of Electricity
• Benjamin Franklin - In 1752, prove
that lightning was electrical, he flew a
kite during a thunderstorm
6
19UEE303 - Electrical Machines – I
• Thomas Edison - In
1879, the American
inventor was finally able
to produce a reliable,
long-lasting electric light
bulb
• Nikola Tesla - In 1887,
developed an Induction Motor

7. 19UEE303 - Electrical Machines – I 7

8. Magnetic circuit
19UEE303 - Electrical Machines – I 8
• The path in space through which magnetic flux
passes
• Uniform cross-sectioned iron core
• Magnetic field within the toroid core is uniform

9. Terms involved in Magnetic Circuits
• Magnetomotive force F = N I
• Magnetic flux φ
• Reluctance R
• Permeability µ
• Magnetic flux density B
• Magnetic field intensity H
19UEE303 - Electrical Machines – I 9