# 12 Difference Between Star and Delta Connections in Three-Phase System

The three-phase AC system is basically designed by two different electrical connections. One is the star connection and the other is the delta connection.

These two connections have different specifications and used to achieve different functionalities. Here, I am describing the what is the difference between star and delta connection in 3 phase system.

This is one of the most important questions. And it has been asked in many of the exams and job interviews. So being an electrical engineer, you must know all the basic concepts and differences between them.

Let’s compare the star and delta wiring in tubular form.

### Star Connection vs Delta Connection

#### 13. Circuit Diagram of Star and Delta connections

• Star Connection or Wiring

In a star connection of three-phase winding, all coils are connected at a common point. This point is called as Star point Neutral (N).

The above star wiring represents the relationship between the phase and line of voltage and current.

Line current and Phase current in delta connection:

1. Line current is represented by IR, IY, and IB
2. Phase current is represented by INR, INY, and INB

Line voltage and Phase voltage in delta connection:

1. Line voltage is represented by the VRY, VYB, and VRB
2. Phase voltage is represented by VNR, VNY, and VNB

Circuit diagram of star connection.

• Delta Connection or Wiring

In a delta connection of a three-phase winding, all coils are connected back to back arrangement.

From the above delta wiring, we will see the the relationship between the phase and line of voltage and current.

Line current and Phase current in star connection:

1. Line current is represented by IR, IY, and IB
2. Phase current is represented by I12, I23, and I31

Line voltage and Phase voltage in star connection:

1. Line voltage is represented by the VRY, VYB, and VRB
2. Phase voltage is represented by V12, V23, and V31

Circuit diagram of delta connection.

Note: Blue remarks represent phase quantities. Red remarks represent line quantities.

This is all about the basic specifications of star connection vs delta connection. These specifications also describe the advantages of star and delta connections.

We will see the drive line and phase relationship of voltage and current for star and delta connected three phase system in an upcoming tutorial.

If you have any queries regarding the comparison between star and delta connections, drop your comment below.

Other Related Comparisons:

Thanks for Reading!

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### 13 thoughts on “12 Difference Between Star and Delta Connections in Three-Phase System”

1. Very useful

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2. Thanks, for posting.

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3. Thanks, Mam.

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4. Good basic information

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5. Love this

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6. Very useful

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• Thanks, Tejasvinee.

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7. Great post, well informed.

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