Electric Circuits - A famous root of 3

The famous root of 3!

One of the big questions of Electrical Engineering students is the concept of Phase Voltage and Line Voltage and how it should be applied to the nominal value multiplied by voltage.

This article aims to shed some light on this issue that causes so much doubt and is of fundamental importance not only for engineers and engineering students but also to all professionals and students working as part of energy and power systems.

1-Phase Voltage and Line Voltage:

In summary we have the following concept,

Phase Voltage: Voltage measured in each of the coils of the generator or the load impedance.

Line Voltage: Voltage measured between two terminals of the generator or load, except the neutral terminal.

Applying this concept to the connections Star (Y) and Triangle (Δ), we have the following settings.

2 - Three phase circuits:

For a three-phase circuit with phase sequence ABC, with modulus of the phase voltages V _F, we have the following for their Phasor diagram of phase voltages.

3 - why the root of three??

We have the following line voltages

Passing the rectangular shape to the polar form, we will have your module and its ângulo.Teremos so the following result:

To calculate the module, we have: