What is the difference between a star and a delta connection?
Star Connected System:
- Star connection is used where we require a Neutral terminal to obtain Phase voltage.
- in a star-connected system VL=√3Vph,mean Phase voltage is root 3 times less than line voltage.
- In a star-connected system IL=I phase.
- Star-connected system require less insulation level.
- Star Connected system is used where low starting current is required.
- this system is good for the distribution line due line current is equal to phase current. So the required size of the conductor will be less.
Delta Connected System.
- In a Delta Connected system Line Voltage is equal to Phase Voltage.
- While phase current is √3 times less than Line current.
- The insulation level is high because line voltage = Phase Voltage.
- is generally used where high starting Torque is required.
- This system is best for transmission lines due less insulation is required as line voltage is equal to phase voltage.
Star is used for high voltage and low current while delta for high current and low voltage. Star got neutral, which leads to the invention of 3 phase four wire system whereas delta has no neutral. Generally, we use star for distribution and delta for transmission, apart from this major application there are several….. like starting of induction motor, etc. Delta connections are meant for only 3 phase load so in our homes they won't be able to do much as supply is single phase.
What happens when it is star connected or delta connected?
In STAR connection, the starting or finishing ends (Similar ends) of three phases(coils) are connected together to form the neutral point. A common wire is taken out from the neutral point which is called Neutral. There is no such connection in Delta network.
The Line voltage is root three times the phase voltage. That means the insulation requirement for each phase is low as compared to delta connection where line voltage is same as phase voltage. Hence the no. of turns in any phase in star connection of the conductors is also less than no of turns of conductors in any phase of delta connection.
The phase voltage is lower than line voltage in star connection, so the motors or drives connected in star connection runs at lower speed as compared to delta connection.
Star Connection is preferable in transmission system as the voltage insulation required is less. Delta connection is used in the Distribution system.
Are the circuits designed in our homes star or delta connected?
In general, Household appliances are supplied with 230 v ac,50 Hz which is a single-phase supply and not three phase supply. Anywhere when the electrical load is more than 5KW, three phase supply is given to reduce the load(in ampere) in any single phase and to avoid the voltage drop across other appliances connected in that phase.
Star and delta connections are used in the 3-phase circuit.
Home are provided with single phase supply by power company so at our home there is neither star nor delta. All the loads are connected in parallel.