Lecture Notes Elements of Electrical Machines
Elements of Electrical Machines
Lecture Notes
Subject Code: BEE 1301
For 3rd Semester Mechanical Engineering and Production Engineering students
1
,Lecture Notes Elements of Electrical Machines
(3RD SEMESTER)
ELEMENTS OF ELECTRICAL MACHINES (3-1-0)
(For Mechanical and Production Engineering Students)
Module Chapter Lecture no. Topics
D.C. Generator 1 Construction and principle of operation
Module I 2 E.M.F. equation, types of generator
3 No load and load characteristics, Voltage build-up of
shunt Generator
4 Voltage regulation, Application
D.C. Motor 5 Back E.M.F, torque and speed equations
6 Speed control of series and shunt motors
7 Characteristics and performance curves
8 Motor starters
9 & 10 Losses and Efficiency of D.C machines
Module II Single phase 11 Construction and principle of operation
Transformer 12 E.M.F. equation
13 Phasor diagram
14 Actual and approximate equivalent circuits
15 Open and short circuit tests, voltage regulation
16 Losses and efficiency
Three Phase 17 Construction and principle of operation
Transformer
18 Connection of three single –phase units in wye, delta,
open delta configurations
19 Autotransformer; conventional transformer connected as
Autotransformer
20 Special Transformers – induction heating and high
impedance and high frequency transformer
2
,Lecture Notes Elements of Electrical Machines
Three- phase 21 construction and principle of operation
Module III alternators 22 E.M.F. equation, distribution and pitch factors
23 Synchronous reactance
24 performance of alternators on no-load and load; Phasor
diagram; voltage regulation
25 power calculations of turbine and hydro-generators
26 synchronization of an alternator
Three-Phase 27 Construction and principle operation
Synchronous 28 & 29 Complete phasor diagrams, V- curves
Motor 30 Starting methods of synchronous motor and applications
Three-Phase 31 Construction of slip ring and squirrel cage type induction
Module IV induction Motor motors
32 Starting and running torque of a three phase induction
motor
33 torque-slip characteristics; maximum torque calculations
34 speed control of induction motors
35 Open and short-circuit tests
36 losses and efficiency
37 starting of induction motors
Single-Phase 38 Construction and principle of operation
Induction Motor
39 Analysis of single phase motor based on double
revolving field theorem
40 Torque slip characteristic, capacitor- start and capacitor
run motors
REFERENCES
[1] I. J. Nagrath & D.P. Kothari, “Theory and problems of Electrical Machines”, TMH Publication, New
Delhi.
[2] B.L.Theraja & A.K.Theraja, “A Text Book of Electrical Technology”, Volume II, S. Chand &
Company Ltd.
[3] P. S. Bhimbra, “Electrical Machinary”, Khanna Publishers, New Delhi.
[4] NPTEL course materials.
[5] http://electrical4u.com/, Electrical4u, online Electrical Engineering study site, accessed on January
3
, Lecture Notes Elements of Electrical Machines
2015.
D.C Generator
An electrical Generator is a machine which converts mechanical energy (or power) into electrical
energy (or power). The generator operates on the principle of the production of dynamically induced emf
i.e., whenever flux is cut by the conductor, dynamically induced emf is produced in it according to the
laws of electromagnetic induction, which will cause a flow of current in the conductor if the circuit is
closed.
Hence, the basic essential parts of an electric generator are:
A magnetic field and
A conductor or conductors which can so move as to cut the flux
In dc generators the field is produced by the field magnets which are stationary. Permanent magnets are
used for very small capacity machines and electromagnets are used for large machines to create magnetic
flux. The conductors are situated on the periphery of the armature being rotated by the prime-mover.
Fig. 1.1 Basics of dc generators
1.1 Practical DC generator construction
4
Elements of Electrical Machines
Lecture Notes
Subject Code: BEE 1301
For 3rd Semester Mechanical Engineering and Production Engineering students
1
,Lecture Notes Elements of Electrical Machines
(3RD SEMESTER)
ELEMENTS OF ELECTRICAL MACHINES (3-1-0)
(For Mechanical and Production Engineering Students)
Module Chapter Lecture no. Topics
D.C. Generator 1 Construction and principle of operation
Module I 2 E.M.F. equation, types of generator
3 No load and load characteristics, Voltage build-up of
shunt Generator
4 Voltage regulation, Application
D.C. Motor 5 Back E.M.F, torque and speed equations
6 Speed control of series and shunt motors
7 Characteristics and performance curves
8 Motor starters
9 & 10 Losses and Efficiency of D.C machines
Module II Single phase 11 Construction and principle of operation
Transformer 12 E.M.F. equation
13 Phasor diagram
14 Actual and approximate equivalent circuits
15 Open and short circuit tests, voltage regulation
16 Losses and efficiency
Three Phase 17 Construction and principle of operation
Transformer
18 Connection of three single –phase units in wye, delta,
open delta configurations
19 Autotransformer; conventional transformer connected as
Autotransformer
20 Special Transformers – induction heating and high
impedance and high frequency transformer
2
,Lecture Notes Elements of Electrical Machines
Three- phase 21 construction and principle of operation
Module III alternators 22 E.M.F. equation, distribution and pitch factors
23 Synchronous reactance
24 performance of alternators on no-load and load; Phasor
diagram; voltage regulation
25 power calculations of turbine and hydro-generators
26 synchronization of an alternator
Three-Phase 27 Construction and principle operation
Synchronous 28 & 29 Complete phasor diagrams, V- curves
Motor 30 Starting methods of synchronous motor and applications
Three-Phase 31 Construction of slip ring and squirrel cage type induction
Module IV induction Motor motors
32 Starting and running torque of a three phase induction
motor
33 torque-slip characteristics; maximum torque calculations
34 speed control of induction motors
35 Open and short-circuit tests
36 losses and efficiency
37 starting of induction motors
Single-Phase 38 Construction and principle of operation
Induction Motor
39 Analysis of single phase motor based on double
revolving field theorem
40 Torque slip characteristic, capacitor- start and capacitor
run motors
REFERENCES
[1] I. J. Nagrath & D.P. Kothari, “Theory and problems of Electrical Machines”, TMH Publication, New
Delhi.
[2] B.L.Theraja & A.K.Theraja, “A Text Book of Electrical Technology”, Volume II, S. Chand &
Company Ltd.
[3] P. S. Bhimbra, “Electrical Machinary”, Khanna Publishers, New Delhi.
[4] NPTEL course materials.
[5] http://electrical4u.com/, Electrical4u, online Electrical Engineering study site, accessed on January
3
, Lecture Notes Elements of Electrical Machines
2015.
D.C Generator
An electrical Generator is a machine which converts mechanical energy (or power) into electrical
energy (or power). The generator operates on the principle of the production of dynamically induced emf
i.e., whenever flux is cut by the conductor, dynamically induced emf is produced in it according to the
laws of electromagnetic induction, which will cause a flow of current in the conductor if the circuit is
closed.
Hence, the basic essential parts of an electric generator are:
A magnetic field and
A conductor or conductors which can so move as to cut the flux
In dc generators the field is produced by the field magnets which are stationary. Permanent magnets are
used for very small capacity machines and electromagnets are used for large machines to create magnetic
flux. The conductors are situated on the periphery of the armature being rotated by the prime-mover.
Fig. 1.1 Basics of dc generators
1.1 Practical DC generator construction
4
