To offer high inductance

To obtain required voltage ratio

To regulate the primary current

To stabilise input and output voltage

To avoid over loading

To maintain constant voltage

To reduce transformer losses

To easy distribution of 3 phase 4 wire system

Self induced emf

Mutually induced emf

Statically induced emf

Dynamically induced emf

Ratio test

Impulse test

Short circuit test

Open circuit test

To reduce the constant losses

To reduce electric interference

To increase the quality of sound

To increase the efficiency of receivers