Working Principle Of Transformer | Step Up [Transformer Diagram] | How to Reduction [Transformer Losses]
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Working Principle Of Transformer

Working Principle of Transformer
What is Transformer?
A transformer is a static electric machine that converts electric power from one circuit to another circuit without changing the frequency
Transformer Working as magnetic induction Principal
The device which is used to stepping up or stepping down of voltages is known as transformer they can step up or step-down alternating voltage only
Transformer windings:-
- Primary Winding
- Secondary Winding
- Laminated iron core
Primary winding:-
. Any winding we give A.C SUPPLY that winding is called primary winding
Secondary winding:-
The winding from which we take the power supply is called secondary winding
Laminated iron core:-
Both primary winding and secondary winding are wrapped around the iron core at both ends
Working Principle of Transformer Full Explanation

Working Principle of transformer When giving A.C supply to primary winding, alternating magnetic flux is generated in the iron core.This alternating magnetic flux cuts both the primary winding and the secondary winding thus forming electro magnetic flux in the secondary winding according to the self induction principle.
Now when the load is connected to the secondary winding the current goes through the load.Thus electric power is transferred from the primary winding to the secondary winding
The emf that can be induced in winding depends on the number of in the winding.
1.Step Up Transformer Diagram

Step up Transformer Diagram is shown above picture
If the number of wound in the secondary winding is greater than the number of wound in the primary winding then the secondary winding induced electro magnetic flux is greater than the primary winding voltage Step up Transformer
Clear explanation at electrical 4u.com
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Step down Transformer

Than the number of wound in the secondary winding If the number of circuits in the primary winding is less than the electro magnetic flux induced in the secondary winding is less than the primary winding voltage we call this step down Transformer
TRANSFORMER LOSSES
1.Load Loss
2.Fixed Loss
Load loss
Load loss occurs when current passes through primary winding and secondary winding.These losses depend on the primary and secondary winding and resistance.These losses vary depending on the load
RESISTENCE =Pl/a
l= conductor length
P=conductor resistance
a=conductor cross section area
Copper Loss
COPPER LOSS =I1squareR1+I2squareR2
I1=primary current
I2=secondary current
R1=primary resistance
R2=secondary resistance
Fixed Loss
hysteresis loss and eddy current loss called as fixed loss
Hysteresis Loss
When the alternating flux is generated in the transformer magnetic core, a cycle of magnetization and de-magnetization occurs in the core.This causes energy loss. This energy loss is called hysteresis loss
Kh = Hysteresis constant
Bm = Maximum flux density
f = frequency
V = core volume
Eddy current loss
When the transformer core is subjected to the A.C magnetic field, the core triggers an emf.This emf core causes an eddy current This eddy current causes eddy current loss
Eddy current loss = Ke Bm f square t square watts/m cube
Ke = eddy current constant
t = core thickness
f=frequency
Bm=maximum flux density
Reduction in Transformer Losses
Transformer losses can be minimized depending on the design and layout of the transformer.Core loss is minimized by using silicon steel core
Using core amorphous steel can also reduce core loss.Using a thin laminated core and stepper joint core can reduce core losses
Since copper resistance value is lower than aluminum, copper winding can be used to reduce copper loss
When operating more than two transformers in parallel, the low-load transformer switches off and distributes its load to the other transformer.Thus the switch off transformer core loss becomes zero
Types of Transformer
1.Core type
2.Shell type
1.Core Type Transformer
Core type construction is more suitable for High voltage transformer coil. The coils are wound around the two limbs of a rectangular magnetic core each limbs carries one half the primary winding and one of the secondary winding so as to reduce the leakage reactance. Insulation are provided between the primary and secondary windings
The L.V winding is wound next to the insulated core and H.V winding is wound over the L.V winding inorder to reduce the amount of insulation required
Small transformers may have core of rectangular or square cross-section with rectangular or circular coils in case of large size transformer stepped cruciform core with circular coil is employed
This type of cores are built with different sizes of laminations. The circular coils with cruciform core provide more mechanical strength especially when short-circuit occurs other advantage of using cruciform core are reduced mean length of turns resulting in reduced copper Loss
Shell type transformer
Shell type construction is more suitable for low voltage transformers. The coils are wound on the central limb of a three limb core the entire flux passes through the central limb the size of the outer limb is half of the central limb. In this type transformer sandwich winding is used
The shell type transformer is built up with E and I shape cores. The laminated E and I cores are assembled to form the magnatic circuit it consists of three limbs one limb is at the centre and two limbs are outer
The H.V windings and L.V windings are placed over the central limb the windings are covered on both sides by cores
Advantages:-
1*Less magnetic loss
*less leakage reactance
*Greater mechanical strength
*Better cooling facility
*Less magnetic current
Disadvantages:-
*Difficult for manufacturing
*Greater difficulty in carrying out repairs
Why Transformer Rating in KVA?
The capacity of the transformer is always expressed in KVA. Rating of the transformer is defined as the maximum power in KVA that the transformer can handle without overheating of its windings when rated voltage at rated frequency is applied to the primary windings
The copper Loss of a transformer depends on voltage. Hence total losses depends on volt ampere only and it is independent of load powerfactor. That is why the rating of transformer is given in KVA and not in KW
Uses Of Two Winding Transformer
1.It is used as Auto Transformer starters for starting the induction motor
2.It is used as instrument transformer for increasing the range of meters
3.It is used in night lamp
4.It is used in Power Supply for Electronic circuit
5.In generating station the transformer step up the voltage for transmission
Do you know Three phase Transformer working? Read more