TRANSFORMERS CLASSIFIED AS PER CORE

There are three types of transformers on the basis of core used between the windings:

1. Core type:

(a) Open core type:

In this type of transformer, the primary and secondary windings are wound on lathered paper spools of cylindrical or cubical shape. Laminated iron cores are fitted inside the spool. These types of transformer are almost out of use now.

(b) Closed Core type:

In this type of transformer L-shaped laminated cores are used which form a closed magnetic path. In this way the leakage of magnetic flux is greatly reduced in this type of transformer which increases the magnitude of electrical energy transferred.

2. Shell type:

In this type of transformer E and I-shaped laminated cores are used. The primary and secondary windings are wound one above the other on the central path of the core. In this way, the magnetic flux is divided into two parts at the center of core and covers both the windings all around. Most of the L.F. and A.F. transformers are of shell type.

3. Berry Type:

This is an improved form of a shell type of transformer. The main core of the transformer is cylindrical are both the winding wound on it. 8 to 10 shell joined to the main core cover the coil all around. In this way, the leakage of magnetic flux is minimized and the efficiency of the transformer is maximized. The transformer is used in special types of circuits.