Introduction to Marine Engineering

In a wye or star configuration, three components are connected at a common point, forming a Y shaped pattern. The common point is designated $N$ for neutral, and the three power lines, designated $A\text{,}$ $B\text{,}$ and $C\text{,}$ are connected to the free ends of the three components.

In three phase circuits, the voltage measured from line to line is called the line voltage,$V_L\text{,}$ and the voltage measured across a component is called the phase voltage ,$V_{\varphi }\text{.}$The line current, $I_L$ ,is the current flowing in a power line, while the phase current, $I_{\varphi }\text{,}$ is the current flowing through a component. In a balanced system, all three line voltage are the same, as are all three line currents.