Question { ISRO, 43178 }

why should we place 9KV lightning arrestors in 11KV
substation ?

Answer

The LA are designed to by pass the high voltage surges so
that the system voltages do not get affected and the
equipment in line are safe. We place 9kv in 11kv substation
becouse it can attract the lightning surges in the 11KV
system with low resistance and can ground quickly.

If anyone want to add more he is welcome.

Question { 3988 }

Why the isolation treasforfer are connected at out put of
the ups ig 200kva ??????????????????

Answer

To creat the neutral.

Question { 26247 }

If there is 25 hp motor,which type of starters we can us? why?

Answer

For a 25 HP Induction motor one should use the star delta
starter. During the starting the motor draws 5 to 7 times
its normal current rating due to high inertia of its
armature. In the star circuit the Il=Tph as a result the
current is high. Its like moving a startionary object from
its position we require high force.

Pls add more.

Question { Divis Laboratories, 11919 }

what is full form of dyn11( in transformer)

Answer

DYn11 Means D=Delta, Y=Star, n=neutral, 11= 5degree phase
shift. This means there is a phase shift of 5 degree from
primary to secondary of a transformer.

Question { Divis Laboratories, 11919 }

what is full form of dyn11( in transformer)

Answer

I correct my self it is a 30 degree phase shift.

Thank's rajesh for your inputs.