How to connect a three-phase generator?

If you have ever wondered how to connect a three-phase generator, from Agresa we will try to explain its characteristics and how to do it in this post.

A three-phase system is composed of three single-phase alternating currents, known as phases, with the same frequency and amplitude, and with a phase difference between them of 120º.

How to connect a three-phase generator, Agresa

If there is a gap between them and this symmetry is broken between the three, the system is said to have become unbalanced.

On the other hand, there are two ways of connecting a three-phase generator, with a star connection or with a delta connection.

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How to connect a three-phase generating set: Delta or star connection

The delta connection consists of connecting the phases of the generating set or the load to each other by joining the beginning of one with the end of the other.

How to connect a three-phase generator, Agresa

In the star connection, on the other hand, all the phases start from the same point, as can be seen in the diagram above.

What are the advantages and disadvantages of three-phase generators?

In a three-phase generating set, the power is distributed among the three phases, so any equipment connected to the set can never exceed one third of the total power, as it could cause significant breakdowns. It is highly recommended to be rigorous with the control of the power that supports each phase, to avoid greater evils.

The main advantage of the three-phase system can be found in the cost of the installation, since, as it has three phases with less power, both the cables and the transformers and other elements are usually smaller than those of the single-phase groups, and the installations are generally a little more economical.

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Generally speaking, a three-phase generator is usually cheaper than a similar single-phase model. This is due to the alternator, since single-phase generators tend to have more power than a similar three-phase model, in order to offer the same degree of efficiency. This, of course, makes the final price of the single-phase more expensive.

This process was very complicated some years ago, but thanks to new technologies, it has become simple, effective and reliable in equal parts. Ask us for information without obligation!

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Diesel generators and installations in places of difficult access

In Agresa we have a long and extensive experience in the installation of generators in complicated places, of great power, and of the most recognized marks of the current market. We have installed our power generation equipment throughout the country, in hospitals, large construction sites, motorcycling and F1 circuits, hydroelectric power stations, communication towers, hydroelectric dams…

On the other hand, it is important to mention that currently all brands have diesel generators, designed to achieve an annual consumption much lower than gasoline, always thinking about continuous or main power equipment.

We also have lines of soundproofed generators, with a view to all those facilities that require silence for the normal development of their activities, such as hospitals, schools, nursing homes …

On the other hand, as it could not be any other way, we like to put in value our exceptional technical team, with a great vocation of service, as well as a high Know How regarding contemporary energy generation and supply equipment.

Ask for information about our products or services without obligation

This sector is somehow complicated, especially when it comes to choosing a genset, type or amount of power. If you have any doubts about how to connect a three-phase generating set, about any of our equipment and brands, or you would like to ask us for an estimate to carry out some of the usual maintenance tasks, don’t waste any more time and contact us by calling 93 877 20 20, or sending an e-mail to You can also fill in the form that can be found at this link.

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Finally, if you would like to keep an eye on all the news from the company or the energy sector and, more specifically, the generating sets… just keep an eye on our blog!

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