A transformer transfers electric power from one circuit to the other by means of electromagnetic induction transferring is done without a change in frequency but there will be changes in magnitudes in voltage and current. The voltage and current levels can be decreased or increased by the transformer while using AC. The two types of transformers are

• Core type transformer

• Shell type transformer

The main difference between these is the windings which are wound around in the magnetic core

Core type transformer

In this type the windings surround a major part of the steel, it requires more conductor material and less iron compared to shell type in this type of transformer the windings encircles the core

The H.V and L.V both are placed in the same limb Main advantages of this type of transformers are • Repair and maintenance is easy • Cooling and ventilation of the windings is easy • Windings are placed concentrically because of this there will be less leakage flux •single-phase is higher and better regulation

in case of single-phase transformers, core type has the two-legged core to reduce the leakage flux half of the L.V winding placed on one leg and the other half is in other leg and it’s the same for H.V winding L.V winding is situated near to the steel core H.V is outside to reduce the insulation

Shell Type Transformer

This type has the three-legged core and the design increases the mechanical strength of the core and it protects the winding from external shocks the H.V and L.V are wound around the central limb to reduce the leakage flux the windings are interleaved and sandwiched

Two types of the winding are done for transformers the concentric coil and interleaved coils. a concentric coil is used for core type and interleaved for shell type

Easy to repair Difficult to repair
leakage flux is more less leakage flux
Better cooling less cooling
more copper used less copper is used
mechanical support is less more mechanical support needed
high power high voltage low power low voltage
less insulation is needed more insulation needed