Acidity

Moisture

Viscosity

Dielectric strength

Soft iron

Rolled steel

Copper alloy

Cold rolled grain oriented

Air releasing

Heat releasing

Pressure releasing

Moisture releasing

Protection from high temperature

Protection from moisture entering in oil

Protection from pressure loading in tank

Protection from both overloading and short circuit

To offer high inductance

To obtain required voltage ratio

To regulate the primary current

To stabilise input and output voltage