Transformers

pulling the motor directly on line without a starter

locking of rotor due to harmonics

starting the motor on load which is more than the rated load

interchanging two supply phases for quick stopping

To provide coupling between primary and secondary

To increase the magnitude of mutual flux

To decrease the magnitude of magnetizing current

To provide all above features

asbestos fiber

silica sand

sodium chloride

silica gel

zoom

hum

ringing

buzz

0.2 to 0.5 per cent

2 to 5 per cent

12 to 15 per cent

20 to 30 per cent

0.2 lagging

0.2 leading

0.5 leading

unity

Ns

s.Ns

(1 - s)Ns

(Ns - 1)s

core

windings

tank

any of the above

ionizing air

absorbing moisture

cleansing the transformer oil

cooling the transformer oil

electrical fault inside the transformer itself

electrical fault outside the transformer in outgoing feeder

for both outside and inside faults

none of the above