Properties of Star and Delta Connection
Some of the important electrical properties of star and delta connection are current and voltage so let us study them individually.
Current and Voltage in Delta Connection
Let us take a look at the circuit and the phasor diagram.
The figure clearly shows us the arrangement in a delta connection. We have assumed that the current flowing in each of the three windings in IR, IY, IB. We will use the phasor diagram to find the relationship between the quantities.
Mathematical Equations
From the phasor diagram
IR = IBR – IRY
and IY = IRY – IYB
and IB = IYB – IBR
Now we will use vector parallelogram law to calculate the equivalent
∴ IR= √(IBR2 +IRY2+ 2IBRIRYcos(60)
We know that for a balanced load, IRY =IBR =IYB =Iph. (Iph is the phase current)
IR= √(Iph2+Iph2+2Iph2 cos(60))
∴ IL= √3 Iph
Also as VRY= VYB= VBR= VL
∴ VL=Vph
Current and Voltage in Star Connection
Let us take a look at the circuit diagram of star connection
The figure shows the arrangement in a delta circuit. We have assumed that there are three phase voltages VR, VY, VB and the corresponding line voltages are VRY, VYB, VBR. We will use the phasor diagram to find the relationship between the quantities.
Mathematical Equations
From the phasor diagram
VR=V Y=VB=Vph
Also VRY =VR +(−V Y)=VR−VY
Now we will use vector parallelogram law to calculate the equivalent
∴ VRY = √(VR2+VY2+2VRVY cos60)
∴ VRY=√(Vph2+ Vph2+2Vph2cos60)
Therefore VL=√3 Vph
From the above calculation, we can say that line voltage is √3 times phase voltage in a star connection. Also from the figure, we can say that load is balanced hence current must be equal
IR=IY=IB=Iph
Delta to Star Conversion
In this article, we will discuss about delta to star conversion. Firstly, we will try to understand the two types of connections i.e. star and delta connections. The understanding will be developed by learning about their characteristics through current and voltage equations in these circuits. We will proceed to see the differences between the star and delta connections based on different parameters. Results will be derived from the beginning to ensure clarity of formulas.
In addition to this, we will look into some solved examples that will help us understand the concept better. Later in the article, we will discuss the applications, advantages, and disadvantages of this conversion. The article will conclude with some frequently asked questions that readers can refer to.
Table of Content
- Star and Delta Connection
- Properties
- Star Vs Delta Connection
- Delta to Star Conversion
- Steps to Solve Conversion
- Solved Example
- Applications
- Advantages
- Disadvantages