Different between Star and Delta Connections

Different between Star and Delta Connections

Star (Y) Connection
Delta (Δ) Connection
In STAR connection, the starting or finishing ends (Similar ends) of three coils are connected together to form the neutral point. A common wire is taken out from the neutral point which is called Neutral.In DELTA connection, the opposite ends of three coils are connected together. In other words, the end of each coil is connected with the start of another coil, and three wires are taken out from the coil joints
There is a Neutral or Star PointNo Neutral Point in Delta Connection
Three phase four wire system is derived from Star Connections (3-Phase, 4 Wires System) We may Also derived 3 Phase 3 Wire System from Star ConnectionThree phase three wire system is derived from Delta Connections (3-Phase, 3 Wires System)
Line Current is Equal to Phase Current. i.e.
Line Current = Phase Current
I= IPH
Line Voltage is Equal to Phase Voltage. i.e.
Line Voltage = Phase Voltage
V= VPH
Line Voltage is √3 times of Phase Voltage. i.e.
VL = √3 VPH
Line Current is √3 times of Phase Current. i.e.
IL = √3 IPH
The Total Power of three phases could be found by
P = √3 x VL x IL x CosФ …. Or
P = 3 x VPH x IPH x CosФ
The Total Power of three phases could be found by
P = √3 x VL x IL x CosФ … or
P = 3 x VPH x IPH x CosФ
The speeds of Star connected motors are slow as they receive 1/√3 voltage.The speeds of Delta connected motors are high because each phase gets the total of line voltage
In Star Connection, the phase voltage is low as 1/√3 of the line voltage, so, it needs low number of turns, hence, saving in copper.In Delta connection, The phase voltage is equal to the line voltage, hence, it needs more number of turns.
Low insulation required as phase voltage is lowHeavy insulation required as Phase voltage = Line Voltage.
In Power Transmission, Star Connection system is general and typical to be used.In Power Distribution and industries, Delta Connection is general and typical to be used.


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