Star connection and Delta connection - Electrical input

Monday, September 3, 2018

STAR CONNECTION AND  DELTA CONNECTION

STAR connection:-  the starting or finishing ends  of three coils are connected together to form the neutral point. A common wire is taken out from the neutral point which is known as Neutral. Star is used for high voltage and low current star connection has three phase four wire system.
Line voltage VL=√3 Vph.   phase voltage
Line Current IL= Iph     phase current

STAR  connection system :-
1.       Star connection is used where we require Neutral terminal
2.       star connected system VL=√3Vph
3.       star Connected system IL=I phase
4.       Require less insulation level
5.       Star is used where high voltage and low current require

What is the use of Star Connection ?
motors or drives connected in star connection runs at lower speed, Star Connection is suitable in transmission system as the voltage insulation required is less. In a squirrel cage motor, the starter is used  to decrease the input voltage to the motor as to decrease starting current.

DELTA connection :- delta connection which is also known as three phase three wire system. it is the  suitable system for AC Power Transmission. opposite ends of three coils are connected together  the end of each coil is connected with the start of another coil, and three wires are taken out from the coil joints. Delta connection used where high current and low voltage require.
Line Voltage VL= Vph.   Phase Voltage
Line current. IL= √3 Iph.   Phase current

DELTA connection system :-
1.       In delta connection line voltage equal to phase voltage
2.       Phase current is √3 times less than Line current
3.       High insulation level
4.       Delta connection used where high starting Torque is required

What is the use of Delta Connection ?
Delta connection is used in Distribution system.  T.P.D.T switch used  for delta connection in running position.

Star/Delta terminal connection shown in the fig below