TYPES OF TRANSFORMERS AND IT’S CONSTRUCTION
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
| CORE TYPE | 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 |