ELECTRICAL MACHINE-I (Ist PPT) Unit-1.pptx

AMIT KUMAR PANDEY 1
GLOBAL INSTITUTE OF TECHNOLGY
JAIPUR
ELECTRICAL MACHINE-I
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)
Topic Name : Introduction of Electrical Machines

Introduction of Electrical Machines :-
An electrical machine is a device which converts mechanical energy
into electrical energy or vice versa. Electrical machines also include transformers,
which do not actually make conversion between mechanical and electrical form
but they convert AC current from one voltage level to another voltage level.
AMIT KUMAR PANDEY 2
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Importance of Electrical Machines:-
Electricity is generated by electrical generators. Electricity is one of the most
important blessings that science has given to mankind. It has also become a part of
modern life and one cannot think of a world without it. Electricity has many uses
in our day to day life. It is used for lighting rooms, working fans and domestic
appliances like using electric stoves, A/C and more. All these provide comfort to
people. In factories, large machines are worked with the help of electricity.
Essential items like food, cloth, paper and many other things are the product of
electricity.
AMIT KUMAR PANDEY 3
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Importance of Electrical Machines:-
Electric motors impact almost every aspect of modern living. Refrigerators,
vacuum cleaners, air conditioners, fans, computer hard drives, automatic car
windows, and multitudes of other appliances and devices all use electric motors to
convert electrical energy into useful mechanical energy.
AMIT KUMAR PANDEY 4
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Classification of Electrical Machines:-
1.DC Machine
1.1 DC Generator
1.2 DC Motor
2.Transformer
2.1 Single Phase Transformer
2.2 Three Phase Transformer
3.Induction Motor
3.1 Three Phase Induction Motor
3.2 Single Phase Induction Motor
4.Synchronous Machine
4.1 Synchronous Generator or Alternator
4.2 Synchronous Motor
5.Special Motors
AMIT KUMAR PANDEY 5
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

DC Machine:-
A DC Machine is an electro-mechanical energy conversion device. ... The
AC motor is invariably applied in the industry for conversion of electrical power
into mechanical power, but at the places where the wide range of speeds and good
speed regulation is required, like in electric traction system, a DC motor is used.
AMIT KUMAR PANDEY 6
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

DC Generator :-
A dc generator is an electrical machine which converts mechanical energy into
direct current electricity. This energy conversion is based on the principle of
production of dynamically induced emf.
They are used for general lighting. They are used to charge battery because they
can be made to give constant output voltage. They are used for giving the
excitation to the alternators. They are also used for small power supply (such as a
portable generator).
AMIT KUMAR PANDEY 7
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

DC Motor :-
A direct current or DC motor, converts electrical energy into mechanical energy. It
is one of two basic types of motors: the other type is the alternating current or
AC motor. Among DC motors, there are shunt-wound, series-wound, compound-
wound and permanent magnet motor.
Small DC motors are used in tools, toys, and appliances. The universal motor can
operate on direct current but is a lightweight brushed motor used for portable
power tools and appliances. Larger DC motors are currently used in propulsion of
electric vehicles, elevator and hoists, and in drives for steel rolling mills
AMIT KUMAR PANDEY 8
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Transformer :-
A transformer is defined as a passive electrical device that transfers electrical
energy from one circuit to another through the process of electromagnetic
induction. It is most commonly used to increase ('step up') or decrease ('step
down') voltage levels between circuits.
A transformer is a device that is used to either raise or lower voltages and currents
in an electrical circuit. In modern electrical distribution systems, transformers are
used to boost voltage levels so as to decrease line losses during transmission.
AMIT KUMAR PANDEY 9
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Single Phase Transformer :-
The single-phase transformers are widely used in commercial low voltage
application as electronic devices. They operate as a step-down voltage transformer
and decrease the home voltage value to the value suitable for electronics supplying
AMIT KUMAR PANDEY 10
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Three Phase Transformer :-
Three Phase transformers are widely used as power transformers,
Distribution transformers and in Electrical Grids. ... Some loads such as industrial,
and commercial require 3 phase transformers to meet their demand. The
transmission voltage such as 132/220 KV, we need step up/down in the both ends
of Transmission lines.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Induction Motor :-
Definition of induction motor. : an alternating current motor in which torque is
produced by the reaction between a varying magnetic field generated in the stator
and the current induced in the coils of the rotor.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Three Phase Induction Motor :-
3 phase induction motor is singly excited a.c machine which is connected to 3
phase supply.in this motor stator is directly connected to supply and rotor get
excited by means of induction(unlike in case of dc motor) while rotor never catch
the speed of stator (synchronous speed).
Three-phase AC induction motors are widely used in industrial and
commercial applications. These are of two types, squirrel cage and slip
ring motors. Squirrel cage motors are widely used due to their rugged construction
and simple design. Slip ring motors require external resistors to have high starting
torque.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Single Phase Induction Motor :-
A Single Phase Induction Motor consists of a single phase winding which is
mounted on the stator of the motor and a cage winding placed on the rotor. A
pulsating magnetic field is produced, when the stator winding of the single-phase
induction motor shown below is energised by a single phase supply.
Single Phase Induction Motor. ... The single phase motors are simple in
construction, cheap in cost, reliable and easy to repair and maintain. Due to all
these advantages, the single phase motor finds its application in vacuum cleaners,
fans, washing machines, centrifugal pumps, blowers, washing machines, etc.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Synchronous Machine:-
A synchronous machine is an electrical machine whose rotating speed is
proportional to the frequency of the alternating current supply and independent of
the load.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Synchronous Generator or Alternator :-
A machine that generates an alternating voltage when its armature or field is
rotated by a motor, an engine, or other means. The output frequency is exactly
proportional to the speed at which the generator is driven.
Synchronous generators are commonly used for variable speed wind
turbine applications, due to their low rotational synchronous speeds that produce
the voltage at grid frequency. ... Using an AVR for the excitation of the field
voltage, the output voltage of the synchronous generator can be controlled.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Synchronous Motor:-
A synchronous electric motor is an AC motor in which, at steady state, the rotation
of the shaft is synchronized with the frequency of the supply current; the rotation
period is exactly equal to an integral number of AC cycles. ... The synchronous
motor and induction motor are the most widely used types of AC motor.
Usually, synchronous motors are used for applications where precise and constant
speed is required. Low power applications of these motors include
positioning machines. These are also applied in robot actuators. Ball mills, clocks,
record player turntables also make use of synchronous motors.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Special Motors:-
 AC Series motors
 Universal motor
 Stepper motor
 Shaded pole motor
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Syllabus of Electrical Machine-I:-
 Magnetic fields and magnetic circuits
 Electromagnetic force and torque
 DC machines
 DC machine - motoring and generation
 Transformers
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

Outcome:-
 The ability to formulate and then analyse the working of any electrical machine
using mathematical model under loaded and unloaded conditions.
 The skill to analyse the response of any electrical machine.
 The ability to troubleshoot the operation of an electrical machine.
 The ability to select a suitable measuring instrument for a given application.
 The ability to estimate and correct deviations in measurements due to the
influence of the instrument and due to the accuracy of the instrument.
JAIPUR
(3EE4-07)
ELECTRICAL ENGG.
(III SEM)

ELECTRICAL MACHINE-I (Ist PPT) Unit-1.pptx

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