Download eddy current loss

DCMT
PRESENTATION
DEVANSH KHARE
(141043109002)
SARTHAK PUROHIT
(131040109048)
Course code - 2130904
• The source side is called Primary
• The load side is called Secondary
• Ideally
1. The resistance of the coils are zero.
2. The relative permeability of the core in
infinite.
3. Zero core or iron loss.
4. Zero leakage flux
CONDITION FOR POLARITY OF 1-Ø
TRANSFORMER
1- Transformer should be properly connected
according to their polarities.
2- The voltage ratings and voltage ratios of the
Transformer should be same
3- The per unit impedances of the transformers
should be equal.
4- The reactance or resistance ratio of the
Transformer should be identical.
POLARITY TEST
What is Transformer Polarity ?
• It is an indication of the direction of current flow through the
High voltage terminal with respect to the direction of current
Flow through the low voltage terminal at any given instant in the
alternating cycle .
•The Polarity of a single phase Transformer may be additive or
subtractive .
Transformer
polarity
Additive polarity
Subtractive
polarity
What is Additive Polarity of
Transformer ?
The Polarity is additive if the voltage across the other two
leads of the winding is greater than that of the high voltage
winding .
What is Subtractive Polarity of
Transformer .
-The polarity is subtractive if the voltage across the other
two leads of the winding is less than that of the
high voltage winding .
SAME POLARITY OF TRANSFORMER
OPPOSITE POLARITY OF
TRANSFORMER
LOSSES IN
TRANSFORMER
-Iron losses ( Constant Losses )
-Cu Losses ( Variable Losses )
COPPER LOSS
-
The power loss (I2R) in the form of heat in the
winding of a Transformer is known as a Copper loss.
This losses also known as a Variable loss .
IRON LOSS
-These losses occur in the core of Transformer due to
the magnetic field. These losses are practically
constant for Transformer . There are Two types of Iron
loss in Transformer .
Iron losses
Hysteresis
Losses
Eddy
Current
Losses
HYSTERESIS LOSS
-When
a magnetic field is applied all the grains of the
magnetic material will orient in the direction of magnetizing
force. The energy required to change the orientation of the
magnetic grains in the direction of the magnetic field is lost
in the form of heat. This loss is called Hysteresis loss.
EDDY CURRENT LOSS
-When an alternating magnetic flux is applied to the iron core
small emf will be induced due to change in flux linkage. This
induced emf will cause small circulating current is called eddy
currents. Eddy current flowing through the material causes I2R
losses in the material.
HOW IDENTIFY THE LOSSES IN
TRANSFORMER?
There are two types of test which are mention as follows
1 Open circuit test
2 Short circuit test
OPEN CIRCUIT TEST
-This test is known as a No Load Test. This test is useful to
determine ;
(1) The no load current I0 and no load power factor Cos ø0 .
(2) The magnetic circuit parameter i.e R0 ,X0 ,IW, Iµ .
(3) This test is use to find out Iron loss in Transformer.
SHORT CIRCUIT TEST
This test is known as a Impedance Test.This test is useful to
determine ;
(1) Equivalent resistance (R01 & R02), equivalent reactance (X01 &
X02 ) and equivalent impedance (Z01 $ Z02) of theTransformer.
(2) This test is use to find out copper losses in Transformer.
HOW TO MINIMIZE IRON LOSS
MINIMIZE HYSTERESIS LOSS
The Hysteresis loss can be minimized:(1)By using good magnetic material
(2)By using less value of Maximum Flux
Density (Bm)
MINIMIZE THE EDDY CURRENT
LOSS
The Eddy current loss can be minimized;
(1)By using less thickness of laminations
(2)By using less value of Maximum flux Density
(Bm)
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