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
Minimizes copper use
Reduces hysteresis loss
Reduces eddy current loss
Reduces the space for core