Question { 8283 }

Initially motor starts with star connection ,after few
timing changes to delta connection, why the motor should
run continously in star connection,it gives high torque &
low current?

Answer

The purpose of starter is to start the motor and to limit
the starting current.we are starting the motor in y-
connetion during this impedence of two windings put across
the line voltage hence the starting current gettinh
redeuced
but the motor rated capacity (out put torque)can only be
obtained when itis changed to delta connection this time
the voltage is incresed bu 1.732 time to meet the torque
(torque is direct proportion to square of supply voltage .