One of the biggest distinctions between the core type and the shell type transformer is that the winding encircles the more in a core type, whereas the core encircles the winding of the transformer in a shell type transformer. Now let us check some key points for both of the transformers.
Core type transformer :
- It has one yoke and two limbs
- Both the limbs are provided with winding and the core is surrounded by windings.
- Winding is less protected by the core
- Leakage flux is more than power transfer less capability
- Series magnetic circuit
- Both limbs have the same cross-sectional area
- More amount of copper is required for winding
- Required less amount of insulating material
- Used high-voltage power transmission applications
- High voltage, small KVA rating transformers are suitable
- Easy to repair
- Better cooling because more surface is exposed to the atmosphere
Shell type transformer :
- It has three limbs and two yokes
- Only the middle limbs are provided with winding and winding ar being surrounded by a core
- More protected by the core
- Leakage flux is less
- Parallel magnetic circuit
- The different cross-sectional area
- Amount of chopper required for winding is less
- Not easy to repair
- Cooling is not very efficient
The key difference between core-type and shell-type transformers are given below.
- The core surrounds the winding in a core-type transformer, whereas the winding surrounds the core of the transformer in a shell-type transformer.
- The core-type transformer has two limbs, and the shell-type transformer has three limbs.
- The lamination is cut in the form of L in the core-type transformer while the lamination is cut in the form of E and L in the shell-type transformer.
- The core-type transformer required less insulation compared to the shell type transformer.
- The mechanical strength of the core-type transformer is low compared to the shell-type transformer.
- The output of the core-type transformer is less as compared to the shell-type transformer because it has more losses.
- There are two magnetic circuits in the core type transformer, whereas one magnetic circuit in the shell type transformer.
- The losses in a transformer of core type are more compared to the transformer of shell type.
- In a core-type transformer, less winding is removed for maintenance, in a shell-type transformer number of the winding are required to remove for maintenance.
- The winding of the shell type transformer is distributed type and hence heat is dissipated naturally, whereas in core type transformer the natural cooling is not possible.
- In core-type transformers, both the primary and secondary windings are placed on the side limbs whereas the winding is placed on the central limbs of the transformer in shell-type transformers.
- There are two magnetic circuits in the core type transformer, whereas one magnetic circuit in the shell type transformer.
- The core type transformer cross-section area is rectangular, whereas the shell type transformer cross-section area is square, cross-sectional two bent, or three bent in shape.
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