Study Star and Delta Conn

 Aim:- To study Star and Delta Connection in 3-Phase AC Circuit.

Apparatus Required:-

S.No:	Name	Range	Type	Quantity
1.	Voltmeter	0-600V	MI	1
2.	Voltmeter	0-300V	MI	1
3.	Ammeter	0-2A	MI	2
4.	Rheostat	100 ohm,5A	Double Tube	3

 

Theory:-  

 

 STAR CONNECTION

 

                          Line Voltage = Voltage between any two line terminals,

                                   V_L =V_RY = V_RB =V_BY

                         Phase Voltage = Voltage between any one line & neutral,

                                  V_PH =V_RN = V_BN = V_YN

                         Line & phase current is equal in case of star connection,

                                    V_RY=V_RN +(-V_YN)

                                 V ²_RY =[V­_RN +(-V_YN)] ²

                                         =V²_RN  + V²_YN + 2V_RN V_YN Cos60

                                      V_L = V_RY = √3 V_PH

Circuit Diagram:-    

             

      

 DELTA CONNECTION

Line Current - Current coming from the line terminal

I_L = I_R = I_B = I_Y

Phase current - It is the current flowing through the load connected between two terminals

                               I_PH = I_RY = I_YB = I_BR

                                              I_R = I_RY - I_BR

                                             I²_R­ = [I_RY + (-I_BR) ]²

                                                    = I²_RY + I²_BR + 2 I_RY I_BR Cos60

                             I_R = I_L = √3 I_PH

 

Circuit Diagram:-     

 

Observation Table:-

Connection	IL(A)	IPH(A)	VL(V)	VPH(V)
Star	1.6	1.6	300	173.2
Delta	3.2	1.84	200	200

 

Result:-

1.     Ratio Of V_L/V_PH = 1.732 for Star Connection

2.     Ratio Of I_L / I_PH  = 1.732 for Delta Connection