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

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

Classification of Transformers contd.. Based on Function I) Power transformer Setup up transformer Step down transformer II) Distribution transformer is always step down 9EE402.3

Classification of Transformers contd… Based on function III) Instrument transformers Current transformers Potential transformers IV) Welding transformers

Classification of Transformers contd… Based on Number of windings Single winding transformer (Auto transformer) Multi winding transformer Single winding T/f 9EE402.3 Multi winding T/f

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

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

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

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

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

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