Electrical power is used by two types of systems - single-phase power systems and three-phase power systems. A Single-phase power system has two wires - phase and neutral whereas a three-phase power system has three live wires. The three-phase power system uses two types of connection - star connection and delta connection. In the previous article, we have discussed about star connection. In this article, we are going to discuss about delta connection. Learning about delta connection is also very important as the learning of star connection.

## What is Delta Connection?

In a three-phase power system, where all three phases are connected in a closed-loop system as shown in the below figure, is called Delta Connection. In the delta connection, all three phases are connected in such a way that it makes the circuit triangular shape. If we assume three coils, then they are connected in end to end. There is no common point available like the star connection. Delta connection is only a three-phase three-wire system. Here, you never get the fourth wire.

## Delta Connection Symbol

Herr, you can see the symbol of delta connection.

## Delta Connection Diagram

Here, you can see the diagram of delta connection.

Here, you can see the endpoint of each coil is connected to the starting point of the next coil, which means opposite terminals of each coil are connected together. Also, you can see there is no common point so neutral does not exist.

## Properties of Delta Connection

1. There is no neutral point in the delta connection.

2. In the delta connection, phase voltage is equal to the line voltage.

3. In the delta connection, the line current is root three times the phase current.

4. In the delta connection, always a high voltage is applied across each winding.

5. Delta connection provides a single voltage. Here, you can not get two different voltages like the star connection.

6. Here all three phases carrying high voltage across to each other.

## Delta Connection Formula

The formula of line current in the delta connection is,

IL = √3 Iphase

where IL - Line Current, Iphase - phase current

The formula of line voltage in delta connection is,

VL = Vphase

where VL - Line Voltage, Vphase - phase voltage

The formula of power in delta connection is,

P = √3 * VL * IL * cosÏ•

## Advantages of Delta Connection

1. Delta connection always provides a high voltage in each phase, so operating electrical devices, machines such as an electric motor can achieve a very high speed and torque.

2. Delta connection is capable to circulate a very high current among the three phases. So, it is best suitable for high current applications.

3. Delta connection provides more electrical balance system in a normal condition, as it is a closed-loop system. It always maintain a balance voltage across each phase.

## Disadvantages of Delta Connection

1. Delta connection provides a single voltage only. It is an important disadvantage over star connection.

2. Here, we cannot get the neutral point, so during the fault or breaking of anyone conductor, it is not possible to balance the other two phases. But in a star connection, it is possible by connecting the neutral point to the ground.

3. As, all the phases carrying high voltage, so more insulation is required for each phase.

4. Single-phase supply cannot be obtained from the three-phase power system.

## Applications and Uses of Delta Connection

1. Delta connection is used for the running of induction motor, as it helps to get more speed and torque.

2. Delta connection is used in high voltage overhead transmission where insulation is not required but the flow of current is an important matter.

3. Delta connection is used to high voltage sensitive devices, machines as it provided more electrical balance in normal conditions.

4. The important advantage of delta connection over star connection is, it never got unbalance, even when unbalance loads are connected to it.