1. Classification of Transformers
Transformers are classified
based upon Number of Phases
Single Phase Transformers
Poly-Phase Transformers
a) 2-phase Transformers
b)3-Phase Transformers

2. Classification of Transformers contd..
Based on construction
1. Core -type
2. Shell -type
3 Berry type

3. Classification of Transformers contd..
Based on Function
I) Power transformer
Setup up transformer
Step down transformer
II) Distribution transformer is always step down
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4. Classification of Transformers contd…
Based on function
III) Instrument transformers
Current transformers
Potential transformers
IV) Welding transformers

5. Classification of Transformers contd…
Based on Number of windings
Single winding transformer (Auto transformer)
Multi winding transformer
Single winding T/f
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Multi winding T/f

6. Classification of Transformers contd..
Based on Type of cooling
I) Air cooled transformers
Natural air cooled transformer
Forced air cooled transformer
Induced air cooled transformer

7. Classification of Transformers
Types of cooling contd..
II) Oil cooled transformer
Oil-filled natural or self cooled transformer
Oil-filled forced air cooled transformer
Oil-filled forced water cooled transformer

8. Classification of Transformers Based on Location Contd..
Indoor transformer
Outdoor transformer
Based on Rating
Low rating transformer
Medium rating transformer
High rating transformer

9. Classification Of Transformers contd..
Based on Frequency
Low frequency or power frequency or audio frequency frequency 50 Hz
High frequency transformer, pulse transformer, radio frequency etc

10. Why Transformer Works on AC Supply only ?
Electro magnetic induction
What happens when a transformer is connected to a
DC supply ?
The flux produced by DC supply does not vary but remains constant in magnitude
As flux remains constant no e.m.f is induced in the primary and secondary

11. As there is no self induced e. m
As there is no self induced e.m.f in the primary winding to oppose the applied voltage
A heavy current will flow through the primary winding
And this large current will result in the damage of the winding