l32 1 ph-tr
DESCRIPTION
TRANSCRIPT
Introduction to Electrical Machinery
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
• Generators AC, DC
• Motors AC (Single Phase, Three Phase), DC
• Transformers AC (Single Phase, Three Phase)
• Transfers energy from one electrical circuit to another without change in frequency.
• Static Device working on principle of electromagnetic induction
• Electric Circuits linked by common magnetic core
• Applications Electric power systems
Power transmission, Distribution Networks
Electronic Circuits
Electric Traction
Transformers
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Primary Side Secondary Side
Core
V1Supply side V2 Load sideN1
N1 = Number of turns on primary
N2
N2 = Number of turns on secondary
Representation
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Physical Model
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
I1
E1E1 E2
E2 V2V2
I2
LOADV1
V1
Ø
• Magnetic Core : Flux path
• Flux Linkages : Primary & Secondary
• Induced Emf : Primary – Self Induced Emf & Secondary – Mutually Induced Emf
Operation
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
YokeYoke
LV windingLV winding
InsulationInsulation
HV windingHV winding
LimbsLimbs
CoreWinding crossover
Primary &Secondary windings
LaminationsLaminations
Construction – Core Type
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Side LimbsSide Limbs
Central LimbCentral Limb LV windingLV winding
InsulationInsulation
HV windingHV winding
YokeYoke
Core
InsulationSecondary
Winding
Yoke
Terminals
LaminationsLaminations
Construction - Shell Type
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
t sin ,Core flux m
)2
πt(sinNω
dt
dNf, eInduced em m
11111 2 ),2
sin( NfNEtEe mmmm where
m11 f N 44.4E , Emf InducedPry
m22 f N 44.4E , Emf Induced Sec
emf equation
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
2
φNf2
2
EEEmfinducedSelfofvalueRMS
ωφNEEmfinducedselfofvalueMaximum
m11max1
m11max
k1
2
1
2
N
N
E
E(Transformation Ratio)(Transformation Ratio)
N2 > N1 : Step Up type
N1 N2
V1 V2
E2 > E1
V2 > V1, I1 > I2
V1 V2
N2 = N1 : 1:1 type
E2 = E1
V2 = V1, I1 = I2
N2 < N1 : Step down type
V1 V2
E2 < E1
V2 < V1, I1 < I2
Transformation Ratio
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
A 250 kVA, 11000 / 415 V, 50 Hz, 1 transformer has 80 turns on the secondary. Determine (a) rated primary and secondary currents (b) primary turns (c) maximum flux (d) emf induced per turn
Ans: (a) 22.73 A, 602.41 A (b) 2120 turns (c) 23.37 mWb (d) 5.1886 Volts /
turn
Exercise
ELE 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal