Question { ABB, 60157 }

how to select a circuit breaker?

Answer

CB is selected on the basis of it's Breaking capacity,
Making capacity, operating voltage, operating
current,system frequency, insulation level & type of use
i.e indoor or outdoor.

Question { Maruti Suzuki, 12234 }

Distribution Transformer are connected in configuration?
a. Star/delta b. delta/star
c. star/star d. delta/delta

Answer

a.delta/star

Question { 17410 }

why are use star delta startor.

Answer

At the time of starting motor draws very high strating
current due to very small armature resistance & absance of
back EMF.
To restrict high starting current,at starting stator is
connected in star & after 5-15sec(depending upon motor use
purpose)delay is connected in Delta with the help of star-
delta starter.
current in star connection: i=(V/1.732)/Z
current in Delta connection: i=V/Z
After 5-15sec motor pick-up it's rated speed & devolp back
EMF.