Three Phase Connecctions

THREE PHASE CONNECTIONS

In single phase system two wires are sufficient for transmitting voltage to the load. i.e., phase and neutral. But in three phase system, two ends of each phase are available to supply voltage to the load. If all six terminals are used independently to supply voltage to load then total six wires will be required and it is very much costly.

To reduce the cost by reducing the number of windings, the three windings are interconnected in particular fashion which gives different three phase connections.

Star-Connection:

The Star Connection is formed by connecting starting or terminating ends of all the three windings together. The common point is called Neutral point. The remaining ends are left free for connecting purpose. The star connection is shown in Figure 1.53.

Delta Connection:

The delta is formed by connecting one end of winding to starting end of other and connections are continued to form a closed loop. The supply terminals are taken out from the three Junction points. The delta connections is shown in Figure 1.54.

Line Voltage and Line Current

potential difference between any two wires of supply is called line voltage.

The current passing through any line is called line current.loinsq ni b

In the Figure 1.55 shown below: