SlideShare a Scribd company logo
1 of 28
By
Ch. Sairam,
Sri Indu College of Engineering & Technology,
Associate Professor, Sheriguda.-501510
1
SICET
PRINCIPLE OF 3 Ø ALTERNATOR
Principle of Operation
•The operation of a synchronous generator is based on Faraday's law
of electromagnetic induction, and in an ac synchronous generator the
generation of emf's is by relative motion of conductors and magnetic
flux.
•These machines can be used as either motors or generators but their
predominant use is in generation.
There are a number of sources of energy used to turn the turbines:-
(a) Gas (b) Steam
(c) Combined cycle (d) Nuclear
(e) Hydro (f) Wind
(g) Wave (h) Photovoltaic
2
SICET
Principle of Operation
Multiple
Pole
Rotor 3
SICET
Principle of Operation
•In constructing a synchronous
machine a point to note is that the
stator is fixed and the poles rotate.
A Cylindrical Rotor
•There are two categories of Synchronous
machines:
(a) those with salient or projecting poles
(b) those with cylindrical rotors
2-pole Cylindrical Rotor
4
SICET
Principle of Operation
A Salient Pole Rotor
4-Pole Salient Rotor 5
SICET
Principle of Operation
Its characteristic feature is that the
armature rotates through a stationary
magnetic field, and the generated AC
is brought to the load by means of
slip rings and brushes.
The revolving-armature alternator is
found only in alternators of small
power rating and is not generally
used. This is because a rotating
armature requires slip rings and
brushes to conduct the current from
the armature to the load.
6
SICET
Principle of Operation
The revolving-field type alternator
has a stationary armature and a
rotating magnetic field.
The generated voltage can be
connected directly to the load
without having to pass across the
slip rings and brushes.
The voltage applied to generate the
rotating field is a small DC voltage
(called a “field excitation” voltage)
7
SICET
Single Phase Alternator
A single-phase alternator has all the
armature conductors connected in series
The stator is two pole. The winding is
wound in two distinct pole groups, both
poles being wound in the same direction
around the stator frame.
The rotor also consists of two pole groups,
adjacent poles being of opposite polarity.
8
SICET
Single Phase Alternator
As the rotor (field) turns, its poles will induce AC voltages in
the stator (armature) windings. Since one rotor pole is in the
same position relative to a stator pole as any other rotor pole,
both the stator poles are cut by equal amounts of magnetic lines
of force at any time. As a result, the voltages induced in the two
poles of the stator winding have the same amplitude or value at
any given instant.
The two poles of the stator
winding are connected to each
other so that the AC voltages
are in phase, so they add.
9
SICET
Three Phase Alternator
The three-phase alternator has
three single-phase windings
spaced so that the voltage
induced in any one is phase-
displaced by 120 degrees from
the other two.
A B C
V
O
L
T
A
G
E
The voltage waveforms
generated across each phase
are drawn on a graph phase-
displaced 120 degrees from
each other.
120O
120O
120O
VA
VB
VC
10
SICET
Three Phase Alternator
•The three phases are independent of each other.
•One point from each winding can be connected to form a neutral
and thus make a wye connection.
•The voltage from this point to any one of the line leads will be the
phase voltage. The line voltage across any two line leads is the vector
sum of the individual phase voltages. The line voltage is 1.73, (3 ),
times the phase voltage.
•Since the windings form only one path for current flow between
phases, the line and phase currents are equal.
11
SICET
Three Phase Alternator
•In the delta connection the line voltages are equal to the phase
voltages, but the line currents will be equal to the vector sum of the
phase currents.
•Since the phases are 120 degrees out of phase, the line current will
be 1.73, (3 ), times the phase current. Both "wye" and the "delta"
connections are used in alternators.
•A three-phase stator can also be connected so that the phases form a
“delta” connection.
12
SICET
Three Phase Stator Connection
A
B
C
Three Phase
DELTA Connected
A
B
C
Three Phase STAR
Connected
13
SICET
Three Phase Alternator
•The frequency of the AC generated by an alternator depends upon
the number of poles and the speed of the rotor
•When a rotor has rotated through an angle so that two adjacent
rotor poles (a north and a south) have passed one winding, the
voltage induced in that one winding will have varied through a
complete cycle of 360 electrical degrees.
•A two pole machine must rotate at twice the speed of a four-pole
machine to generate the same frequency.
•The magnitude of the voltage generated by an alternator can be
varied by adjusting the current on the rotor which changes the
strength of the magnetic field.
14
SICET
•A two pole alternator produces one electrical cycle for each complete
mechanical rotation.
•A four pole alternator will produce two electrical cycles for each
mechanical rotation because two north and two south poles move by
each winding on the stator for one complete revolution of the rotor.
Three Phase Alternator
f = (nRotor)(p/2)/60 = (nRotorp)/120
where nRotor is the speed of the rotor in revolutions per minute,
p is the number of poles
f is the electrical line frequency produced by the alternator.
The speed of the rotor must be divided by 60 to change from
revolutions per minute to revolutions per second. 15
SICET
Three Phase Alternator
16
SICET
Three Phase Alternator
•In an alternator the output voltage varies with the load.
•There are two voltage drops.{ IR & IXL }
•The IXL drop is due to the inductive reactance of the armature
windings.
•Both the IR drop and the IXL drop decrease the output voltage as the
load increases.
•The change in voltage from no-load to full-load is called the “voltage
regulation” of an alternator.
•A constant voltage output from an alternator is maintained by
varying the field strength as required by changes in load.
17
SICET
OPEN CIRCUIT CHARACTERISTICS
a.c.
Armature
Circuit
Ea
Ea
Ea
V
Zs
Zs
Zs
DC
Source
A
FL
F
L
ZZ
Z
Field
Regulator
Field Current
To obtain the open circuit characteristics the machine is driven at
rated speed without the load. Readings of the line-to-line voltage are
taken for various values of field current. The voltage, except in very
low voltage machines, is stepped down by the means of a potential
transformer. 18
SICET
OPEN CIRCUIT CHARACTERISTICS
Field Current/A
Armature
Phase
Voltage/V
If not for the magnetic saturation of the iron, the open
circuit characteristics would be linear as represented
by the air gap line 19
SICET
OPEN CIRCUIT CHARACTERISTICS
On open circuit IL = Ia = 0
Vt = E - ILZs
where Zs = Ra + jXs
and Xs = XL + Xar
On open circuit Vt = E
Alternating current produces a flux which is proportional to IL
(reduces the total flux).
This is called the armature reactance effect represented by Xar
On open circuit Xar = 0.
20
SICET
SHORT CIRCUIT CHARACTERISTICS
a.c.
Armature
Circuit
Ea
Ea
Ea
Zs
Zs
Zs
DC
Source
A
FL
F
L
ZZ
Z
Field
Regulator
Field Current
A
short
circuit
The three terminals of the armature are short circuited
The machine is driven at approximately synchronous rated speed and
measurements of armature short circuit currents are made for various
values of field currents usually up to and above rated armature
current. 21
SICET
SHORT CIRCUIT CHARACTERISTICS
Field Current (If)/A
Short
Circuit
Current(I
s.c
)
/A
In conventional synchronous machines the short circuit characteristics
is practically linear because the iron is unsaturated up to rated
armature current
On short-circuit the machine runs
at it synchronous speed (n = ns)
and IL = IFL
For s/c Vt = 0,
Therefore E / IL = Zs
and Isc = IL = E / Zs
22
SICET
a.c.
Armature
Circuit
Ea
Ea
Ea
V
Zs
Zs
Zs
DC
Source
A
FL
F
L
ZZ
Z
Field
Regulator
Field Current
Load
Bank
Delta/Star
Connected
A
a.c.
LOAD CONDITIONS
The machine is introduced to normal working conditions
23
SICET
Per Phase Equivalent Circuit
Ra => armature resistance per phase
XL => leakage reactance.
24
SICET
Power flow out of a Synchronous Machine
Generator power
flow => out
Motor power flow
=> in
25
SICET
Power flow out of a Synchronous Machine
In practical synchronous machines, except for small ones,
Xs >> Ra so we could assume that Zs = jXs in the analysis.
Therefore we get E = Vt + jILXs
 = Load angles
s
L
t jX
.
I
0
V
δ
E 





26
SICET
Power flow out of a Synchronous Machine
Power = VIcos
Considering the diagram h = ILXscos = Esin
Therefore ILXscos = Esin 27
SICET
Power flow out of a Synchronous Machine
For maximum power sin = 1
Therefore  = 90
In which case
28
SICET

More Related Content

Similar to Synchmachine-1.ppt

DC Machines with explanation in detail of everything
DC Machines with explanation in detail of everythingDC Machines with explanation in detail of everything
DC Machines with explanation in detail of everythingOmer292805
 
Induction Motor, three phase induction motor
Induction Motor, three phase induction motorInduction Motor, three phase induction motor
Induction Motor, three phase induction motorAniket Raj
 
Major project
Major projectMajor project
Major projectMusi Raju
 
Ccccccccccccccccccc
CccccccccccccccccccCcccccccccccccccccc
CccccccccccccccccccMusi Raju
 
electrical-actuation-systems.ppt
electrical-actuation-systems.pptelectrical-actuation-systems.ppt
electrical-actuation-systems.pptPiyushGupta632209
 
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].ppt
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].pptIncomplete PPT on first topic.pptx [Autosaved] [Autosaved].ppt
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].pptShubhobrataRudr
 
DC_Machines_week_4.ppt
DC_Machines_week_4.pptDC_Machines_week_4.ppt
DC_Machines_week_4.pptkiran93845
 
POWER SYSTEM ANALYSIS-3
POWER SYSTEM ANALYSIS-3POWER SYSTEM ANALYSIS-3
POWER SYSTEM ANALYSIS-3M Ugur Kebir
 
Synchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarSynchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarMitesh Kumar
 
Synchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarSynchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarMitesh Kumar
 
Unit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptUnit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptPapitaChavan
 
Induction_Motor.ppt
Induction_Motor.pptInduction_Motor.ppt
Induction_Motor.pptssusere58e49
 
Unit8-Induction_Motor working detail.ppt
Unit8-Induction_Motor working detail.pptUnit8-Induction_Motor working detail.ppt
Unit8-Induction_Motor working detail.pptGOYALJAYA
 
Unit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptUnit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptMdSazibMollik
 
Synchronous Generator.pdf
Synchronous Generator.pdfSynchronous Generator.pdf
Synchronous Generator.pdfasmasharab1
 

Similar to Synchmachine-1.ppt (20)

2433476.ppt
2433476.ppt2433476.ppt
2433476.ppt
 
DC Machines with explanation in detail of everything
DC Machines with explanation in detail of everythingDC Machines with explanation in detail of everything
DC Machines with explanation in detail of everything
 
AC generator
AC generatorAC generator
AC generator
 
Alternator
AlternatorAlternator
Alternator
 
Induction Motor, three phase induction motor
Induction Motor, three phase induction motorInduction Motor, three phase induction motor
Induction Motor, three phase induction motor
 
Major project
Major projectMajor project
Major project
 
Ccccccccccccccccccc
CccccccccccccccccccCcccccccccccccccccc
Ccccccccccccccccccc
 
electrical-actuation-systems.ppt
electrical-actuation-systems.pptelectrical-actuation-systems.ppt
electrical-actuation-systems.ppt
 
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].ppt
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].pptIncomplete PPT on first topic.pptx [Autosaved] [Autosaved].ppt
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].ppt
 
Lecture 6
Lecture 6Lecture 6
Lecture 6
 
DC_Machines_week_4.ppt
DC_Machines_week_4.pptDC_Machines_week_4.ppt
DC_Machines_week_4.ppt
 
POWER SYSTEM ANALYSIS-3
POWER SYSTEM ANALYSIS-3POWER SYSTEM ANALYSIS-3
POWER SYSTEM ANALYSIS-3
 
DC_Machines.ppt
DC_Machines.pptDC_Machines.ppt
DC_Machines.ppt
 
Synchronous machine by Mitesh Kumar
Synchronous machine by Mitesh KumarSynchronous machine by Mitesh Kumar
Synchronous machine by Mitesh Kumar
 
Synchronous machine Mitesh Kumar
Synchronous machine Mitesh KumarSynchronous machine Mitesh Kumar
Synchronous machine Mitesh Kumar
 
Unit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptUnit8-Induction_Motor.ppt
Unit8-Induction_Motor.ppt
 
Induction_Motor.ppt
Induction_Motor.pptInduction_Motor.ppt
Induction_Motor.ppt
 
Unit8-Induction_Motor working detail.ppt
Unit8-Induction_Motor working detail.pptUnit8-Induction_Motor working detail.ppt
Unit8-Induction_Motor working detail.ppt
 
Unit8-Induction_Motor.ppt
Unit8-Induction_Motor.pptUnit8-Induction_Motor.ppt
Unit8-Induction_Motor.ppt
 
Synchronous Generator.pdf
Synchronous Generator.pdfSynchronous Generator.pdf
Synchronous Generator.pdf
 

More from deepaMS4

the cop and the anthem.pptx
the cop and the anthem.pptxthe cop and the anthem.pptx
the cop and the anthem.pptxdeepaMS4
 
FRAME RELAY NETWORK.ppt
FRAME RELAY NETWORK.pptFRAME RELAY NETWORK.ppt
FRAME RELAY NETWORK.pptdeepaMS4
 
Chapter17.ppt
Chapter17.pptChapter17.ppt
Chapter17.pptdeepaMS4
 
time domain analysis.pptx
time domain analysis.pptxtime domain analysis.pptx
time domain analysis.pptxdeepaMS4
 
dtei-180910104911-converted.pptx
dtei-180910104911-converted.pptxdtei-180910104911-converted.pptx
dtei-180910104911-converted.pptxdeepaMS4
 
DE UNIT1.pptx
DE UNIT1.pptxDE UNIT1.pptx
DE UNIT1.pptxdeepaMS4
 
Unit 3- DC Machines.pdf
Unit 3- DC Machines.pdfUnit 3- DC Machines.pdf
Unit 3- DC Machines.pdfdeepaMS4
 
unit-1-Three phase circuits and power systems.pptx
unit-1-Three phase circuits and power systems.pptxunit-1-Three phase circuits and power systems.pptx
unit-1-Three phase circuits and power systems.pptxdeepaMS4
 
unit-1-Three phase circuits and power systems.pdf
unit-1-Three phase circuits and power systems.pdfunit-1-Three phase circuits and power systems.pdf
unit-1-Three phase circuits and power systems.pdfdeepaMS4
 
Unit 2 - Transformers.pdf
Unit 2 - Transformers.pdfUnit 2 - Transformers.pdf
Unit 2 - Transformers.pdfdeepaMS4
 
MOSFET.ppt
MOSFET.pptMOSFET.ppt
MOSFET.pptdeepaMS4
 
chapter 5 (1).pptx
chapter 5 (1).pptxchapter 5 (1).pptx
chapter 5 (1).pptxdeepaMS4
 

More from deepaMS4 (13)

the cop and the anthem.pptx
the cop and the anthem.pptxthe cop and the anthem.pptx
the cop and the anthem.pptx
 
FRAME RELAY NETWORK.ppt
FRAME RELAY NETWORK.pptFRAME RELAY NETWORK.ppt
FRAME RELAY NETWORK.ppt
 
Chapter17.ppt
Chapter17.pptChapter17.ppt
Chapter17.ppt
 
time domain analysis.pptx
time domain analysis.pptxtime domain analysis.pptx
time domain analysis.pptx
 
dtei-180910104911-converted.pptx
dtei-180910104911-converted.pptxdtei-180910104911-converted.pptx
dtei-180910104911-converted.pptx
 
DE UNIT1.pptx
DE UNIT1.pptxDE UNIT1.pptx
DE UNIT1.pptx
 
Unit 3- DC Machines.pdf
Unit 3- DC Machines.pdfUnit 3- DC Machines.pdf
Unit 3- DC Machines.pdf
 
unit-1-Three phase circuits and power systems.pptx
unit-1-Three phase circuits and power systems.pptxunit-1-Three phase circuits and power systems.pptx
unit-1-Three phase circuits and power systems.pptx
 
unit-1-Three phase circuits and power systems.pdf
unit-1-Three phase circuits and power systems.pdfunit-1-Three phase circuits and power systems.pdf
unit-1-Three phase circuits and power systems.pdf
 
Unit 2 - Transformers.pdf
Unit 2 - Transformers.pdfUnit 2 - Transformers.pdf
Unit 2 - Transformers.pdf
 
MOSFET.ppt
MOSFET.pptMOSFET.ppt
MOSFET.ppt
 
bjt1.ppt
bjt1.pptbjt1.ppt
bjt1.ppt
 
chapter 5 (1).pptx
chapter 5 (1).pptxchapter 5 (1).pptx
chapter 5 (1).pptx
 

Recently uploaded

(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...
(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...
(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...ranjana rawat
 
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130Suhani Kapoor
 
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130Suhani Kapoor
 
Coefficient of Thermal Expansion and their Importance.pptx
Coefficient of Thermal Expansion and their Importance.pptxCoefficient of Thermal Expansion and their Importance.pptx
Coefficient of Thermal Expansion and their Importance.pptxAsutosh Ranjan
 
SPICE PARK APR2024 ( 6,793 SPICE Models )
SPICE PARK APR2024 ( 6,793 SPICE Models )SPICE PARK APR2024 ( 6,793 SPICE Models )
SPICE PARK APR2024 ( 6,793 SPICE Models )Tsuyoshi Horigome
 
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINE
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINEMANUFACTURING PROCESS-II UNIT-2 LATHE MACHINE
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINESIVASHANKAR N
 
Introduction and different types of Ethernet.pptx
Introduction and different types of Ethernet.pptxIntroduction and different types of Ethernet.pptx
Introduction and different types of Ethernet.pptxupamatechverse
 
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICS
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICSAPPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICS
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICSKurinjimalarL3
 
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...Dr.Costas Sachpazis
 
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...Christo Ananth
 
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...Call girls in Ahmedabad High profile
 
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur Escorts
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur EscortsCall Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur Escorts
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur EscortsCall Girls in Nagpur High Profile
 
Top Rated Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
Top Rated  Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...Top Rated  Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
Top Rated Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...Call Girls in Nagpur High Profile
 
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...ranjana rawat
 
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).pptssuser5c9d4b1
 
Software Development Life Cycle By Team Orange (Dept. of Pharmacy)
Software Development Life Cycle By  Team Orange (Dept. of Pharmacy)Software Development Life Cycle By  Team Orange (Dept. of Pharmacy)
Software Development Life Cycle By Team Orange (Dept. of Pharmacy)Suman Mia
 
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICSHARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICSRajkumarAkumalla
 
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur Escorts
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur EscortsHigh Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur Escorts
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur EscortsCall Girls in Nagpur High Profile
 

Recently uploaded (20)

(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...
(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...
(SHREYA) Chakan Call Girls Just Call 7001035870 [ Cash on Delivery ] Pune Esc...
 
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130
VIP Call Girls Service Kondapur Hyderabad Call +91-8250192130
 
★ CALL US 9953330565 ( HOT Young Call Girls In Badarpur delhi NCR
★ CALL US 9953330565 ( HOT Young Call Girls In Badarpur delhi NCR★ CALL US 9953330565 ( HOT Young Call Girls In Badarpur delhi NCR
★ CALL US 9953330565 ( HOT Young Call Girls In Badarpur delhi NCR
 
Call Us -/9953056974- Call Girls In Vikaspuri-/- Delhi NCR
Call Us -/9953056974- Call Girls In Vikaspuri-/- Delhi NCRCall Us -/9953056974- Call Girls In Vikaspuri-/- Delhi NCR
Call Us -/9953056974- Call Girls In Vikaspuri-/- Delhi NCR
 
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130
VIP Call Girls Service Hitech City Hyderabad Call +91-8250192130
 
Coefficient of Thermal Expansion and their Importance.pptx
Coefficient of Thermal Expansion and their Importance.pptxCoefficient of Thermal Expansion and their Importance.pptx
Coefficient of Thermal Expansion and their Importance.pptx
 
SPICE PARK APR2024 ( 6,793 SPICE Models )
SPICE PARK APR2024 ( 6,793 SPICE Models )SPICE PARK APR2024 ( 6,793 SPICE Models )
SPICE PARK APR2024 ( 6,793 SPICE Models )
 
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINE
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINEMANUFACTURING PROCESS-II UNIT-2 LATHE MACHINE
MANUFACTURING PROCESS-II UNIT-2 LATHE MACHINE
 
Introduction and different types of Ethernet.pptx
Introduction and different types of Ethernet.pptxIntroduction and different types of Ethernet.pptx
Introduction and different types of Ethernet.pptx
 
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICS
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICSAPPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICS
APPLICATIONS-AC/DC DRIVES-OPERATING CHARACTERISTICS
 
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
 
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
 
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...
High Profile Call Girls Dahisar Arpita 9907093804 Independent Escort Service ...
 
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur Escorts
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur EscortsCall Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur Escorts
Call Girls Service Nagpur Tanvi Call 7001035870 Meet With Nagpur Escorts
 
Top Rated Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
Top Rated  Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...Top Rated  Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
Top Rated Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
 
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...
(ANJALI) Dange Chowk Call Girls Just Call 7001035870 [ Cash on Delivery ] Pun...
 
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt
247267395-1-Symmetric-and-distributed-shared-memory-architectures-ppt (1).ppt
 
Software Development Life Cycle By Team Orange (Dept. of Pharmacy)
Software Development Life Cycle By  Team Orange (Dept. of Pharmacy)Software Development Life Cycle By  Team Orange (Dept. of Pharmacy)
Software Development Life Cycle By Team Orange (Dept. of Pharmacy)
 
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICSHARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
 
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur Escorts
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur EscortsHigh Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur Escorts
High Profile Call Girls Nagpur Meera Call 7001035870 Meet With Nagpur Escorts
 

Synchmachine-1.ppt

  • 1. By Ch. Sairam, Sri Indu College of Engineering & Technology, Associate Professor, Sheriguda.-501510 1 SICET PRINCIPLE OF 3 Ø ALTERNATOR
  • 2. Principle of Operation •The operation of a synchronous generator is based on Faraday's law of electromagnetic induction, and in an ac synchronous generator the generation of emf's is by relative motion of conductors and magnetic flux. •These machines can be used as either motors or generators but their predominant use is in generation. There are a number of sources of energy used to turn the turbines:- (a) Gas (b) Steam (c) Combined cycle (d) Nuclear (e) Hydro (f) Wind (g) Wave (h) Photovoltaic 2 SICET
  • 4. Principle of Operation •In constructing a synchronous machine a point to note is that the stator is fixed and the poles rotate. A Cylindrical Rotor •There are two categories of Synchronous machines: (a) those with salient or projecting poles (b) those with cylindrical rotors 2-pole Cylindrical Rotor 4 SICET
  • 5. Principle of Operation A Salient Pole Rotor 4-Pole Salient Rotor 5 SICET
  • 6. Principle of Operation Its characteristic feature is that the armature rotates through a stationary magnetic field, and the generated AC is brought to the load by means of slip rings and brushes. The revolving-armature alternator is found only in alternators of small power rating and is not generally used. This is because a rotating armature requires slip rings and brushes to conduct the current from the armature to the load. 6 SICET
  • 7. Principle of Operation The revolving-field type alternator has a stationary armature and a rotating magnetic field. The generated voltage can be connected directly to the load without having to pass across the slip rings and brushes. The voltage applied to generate the rotating field is a small DC voltage (called a “field excitation” voltage) 7 SICET
  • 8. Single Phase Alternator A single-phase alternator has all the armature conductors connected in series The stator is two pole. The winding is wound in two distinct pole groups, both poles being wound in the same direction around the stator frame. The rotor also consists of two pole groups, adjacent poles being of opposite polarity. 8 SICET
  • 9. Single Phase Alternator As the rotor (field) turns, its poles will induce AC voltages in the stator (armature) windings. Since one rotor pole is in the same position relative to a stator pole as any other rotor pole, both the stator poles are cut by equal amounts of magnetic lines of force at any time. As a result, the voltages induced in the two poles of the stator winding have the same amplitude or value at any given instant. The two poles of the stator winding are connected to each other so that the AC voltages are in phase, so they add. 9 SICET
  • 10. Three Phase Alternator The three-phase alternator has three single-phase windings spaced so that the voltage induced in any one is phase- displaced by 120 degrees from the other two. A B C V O L T A G E The voltage waveforms generated across each phase are drawn on a graph phase- displaced 120 degrees from each other. 120O 120O 120O VA VB VC 10 SICET
  • 11. Three Phase Alternator •The three phases are independent of each other. •One point from each winding can be connected to form a neutral and thus make a wye connection. •The voltage from this point to any one of the line leads will be the phase voltage. The line voltage across any two line leads is the vector sum of the individual phase voltages. The line voltage is 1.73, (3 ), times the phase voltage. •Since the windings form only one path for current flow between phases, the line and phase currents are equal. 11 SICET
  • 12. Three Phase Alternator •In the delta connection the line voltages are equal to the phase voltages, but the line currents will be equal to the vector sum of the phase currents. •Since the phases are 120 degrees out of phase, the line current will be 1.73, (3 ), times the phase current. Both "wye" and the "delta" connections are used in alternators. •A three-phase stator can also be connected so that the phases form a “delta” connection. 12 SICET
  • 13. Three Phase Stator Connection A B C Three Phase DELTA Connected A B C Three Phase STAR Connected 13 SICET
  • 14. Three Phase Alternator •The frequency of the AC generated by an alternator depends upon the number of poles and the speed of the rotor •When a rotor has rotated through an angle so that two adjacent rotor poles (a north and a south) have passed one winding, the voltage induced in that one winding will have varied through a complete cycle of 360 electrical degrees. •A two pole machine must rotate at twice the speed of a four-pole machine to generate the same frequency. •The magnitude of the voltage generated by an alternator can be varied by adjusting the current on the rotor which changes the strength of the magnetic field. 14 SICET
  • 15. •A two pole alternator produces one electrical cycle for each complete mechanical rotation. •A four pole alternator will produce two electrical cycles for each mechanical rotation because two north and two south poles move by each winding on the stator for one complete revolution of the rotor. Three Phase Alternator f = (nRotor)(p/2)/60 = (nRotorp)/120 where nRotor is the speed of the rotor in revolutions per minute, p is the number of poles f is the electrical line frequency produced by the alternator. The speed of the rotor must be divided by 60 to change from revolutions per minute to revolutions per second. 15 SICET
  • 17. Three Phase Alternator •In an alternator the output voltage varies with the load. •There are two voltage drops.{ IR & IXL } •The IXL drop is due to the inductive reactance of the armature windings. •Both the IR drop and the IXL drop decrease the output voltage as the load increases. •The change in voltage from no-load to full-load is called the “voltage regulation” of an alternator. •A constant voltage output from an alternator is maintained by varying the field strength as required by changes in load. 17 SICET
  • 18. OPEN CIRCUIT CHARACTERISTICS a.c. Armature Circuit Ea Ea Ea V Zs Zs Zs DC Source A FL F L ZZ Z Field Regulator Field Current To obtain the open circuit characteristics the machine is driven at rated speed without the load. Readings of the line-to-line voltage are taken for various values of field current. The voltage, except in very low voltage machines, is stepped down by the means of a potential transformer. 18 SICET
  • 19. OPEN CIRCUIT CHARACTERISTICS Field Current/A Armature Phase Voltage/V If not for the magnetic saturation of the iron, the open circuit characteristics would be linear as represented by the air gap line 19 SICET
  • 20. OPEN CIRCUIT CHARACTERISTICS On open circuit IL = Ia = 0 Vt = E - ILZs where Zs = Ra + jXs and Xs = XL + Xar On open circuit Vt = E Alternating current produces a flux which is proportional to IL (reduces the total flux). This is called the armature reactance effect represented by Xar On open circuit Xar = 0. 20 SICET
  • 21. SHORT CIRCUIT CHARACTERISTICS a.c. Armature Circuit Ea Ea Ea Zs Zs Zs DC Source A FL F L ZZ Z Field Regulator Field Current A short circuit The three terminals of the armature are short circuited The machine is driven at approximately synchronous rated speed and measurements of armature short circuit currents are made for various values of field currents usually up to and above rated armature current. 21 SICET
  • 22. SHORT CIRCUIT CHARACTERISTICS Field Current (If)/A Short Circuit Current(I s.c ) /A In conventional synchronous machines the short circuit characteristics is practically linear because the iron is unsaturated up to rated armature current On short-circuit the machine runs at it synchronous speed (n = ns) and IL = IFL For s/c Vt = 0, Therefore E / IL = Zs and Isc = IL = E / Zs 22 SICET
  • 24. Per Phase Equivalent Circuit Ra => armature resistance per phase XL => leakage reactance. 24 SICET
  • 25. Power flow out of a Synchronous Machine Generator power flow => out Motor power flow => in 25 SICET
  • 26. Power flow out of a Synchronous Machine In practical synchronous machines, except for small ones, Xs >> Ra so we could assume that Zs = jXs in the analysis. Therefore we get E = Vt + jILXs  = Load angles s L t jX . I 0 V δ E       26 SICET
  • 27. Power flow out of a Synchronous Machine Power = VIcos Considering the diagram h = ILXscos = Esin Therefore ILXscos = Esin 27 SICET
  • 28. Power flow out of a Synchronous Machine For maximum power sin = 1 Therefore  = 90 In which case 28 SICET