To disconnect the tappings from neutral point

To disconnect the moving contact of the diverter

To avoid heavy sparking at the contact points

To provide an electrical isolation for the windings

Nature of load

Type of cooling

Phase sequence

Class of insulation used

Use of laminated core

By reducing core thickness

By using grain oriented core

Use stepped core arrangement

Pulse transformers

Ignition transformers

Potential transformers

Constant voltage transformers

Using silica gel

Using transformer oil

Using sodium chloride

Using ammonium jelly