Should We Choose Three Phase Generator or Single Generator

When we want to purchase diesel generator, will you consider to buy three phase generator or single generator? Today Dingbo Power shares an article to let you learn them. Hope it can help you to make decision. 

One of the most important components of diesel generator set is its generator, which is a machine responsible for converting primary mechanical energy into electrical energy, usually in the form of alternating current. It also defines whether the generator set is three-phase or single-phase, regardless of the type of fuel and engine.

Power generation is based on Faraday's law, which defines the generation of electromotive force in a conductor moving in a magnetic field. In a single-phase system, there is a magnetic field that moves due to the rotation generated by the internal combustion engine. The magnetic field will be generated by magnetic elements (or magnets) or electromagnets that must be powered by external auxiliary power supply.

However, in the three-phase system, power generation is generated by three magnetic fields with an angle of 120°, which form the three magnetic poles of the three-phase system. Due to the advent of power electronics technology and low price in the past few years, we can find single-phase inverter generator sets in the market. In fact, these are three-phase generators. An electronic converter is added at the power output end to convert the three-phase of the generator into a single-phase system with the help of electronic equipment. In this way, it provides the advantages of three-phase generator and the versatility of electronic converter.

Single Phase generator

Single phase networks are usually used for home use and small three-level installations and services. Why? Because the transmission efficiency of electric energy in three-phase AC is higher, in addition, the effect of basic motor in three-phase system is better. This is why most competent authorities and power companies do not allow single-phase power supply exceeding 10KVA.

For this reason, single-phase machines (including generator sets) usually do not exceed this power. In these cases, reconnected three-phase alternators are usually used so that they can work in single phase, although this means considerable losses (40% or more) depending on the model and alternator manufacturer.

The use of single-phase reconnected three-phase alternators is also common for a variety of reasons (delivery time, inventory, etc.). In addition to the fact that the alternator can be reconnected to three phases (when the three-phase installation changes for some reason), the alternator is still equally effective. In addition, if the engine power is higher, it can provide an alternative to the original three-phase power.

Diesel or gasoline engine

Because they are common at low power rates, single-phase generators are less robust and easier to operate than three-phase generators. With these features, some machines can operate in a discontinuous manner for several hours, which is also common for engines driving single-phase generators.

In these cases, in addition to diesel and gas systems, it is possible to find gasoline engines in this small power range. In general, single-phase diesel generators are designed for using in small place where there is no power grid. Home and businesses that need backup systems to provide energy in the event of a main power failure are usually several hours, because the power outage should not last for a long time due to the existence of a strong power network.

Three phase diesel generator set

Three phase diesel generator set is undoubtedly the biggest reference in this kind of machine. They can be found in almost any power range, and their intensive use and proven efficiency make them more compact, stronger and more efficient than single-phase generator sets.

These advantages mainly come from the motor (generator), but they also affect the engine in many related aspects.

Three phase diesel generators are usually more compact than single-phase diesel generators because it can benefit from current effect and zero flux, which means that less iron and copper are required in the motor to move the same power. This makes them more efficient in the generation and transmission of electric energy. On the other hand, due to the structure of the magnetic circuit itself, the three-phase diesel generator is often more efficient.

Another effect that may not be well known is that single-phase motors have a pair of poles, while three-phase motors have three poles. This makes the torque absorbed by the three-phase generator rounder. Therefore, the mechanical transmission system, bearings and other components are not only less worn, but also more balanced. The friction heating of three-phase motors is also low, which increases durability and reduces maintenance work. The larger the motor, the more significant these effects are.

The three cameras in the diesel generator set are solid and reliable. They have been fully tested for a long time in various cases and achieved good results. Therefore, they are an important part of almost any complex project: hospitals, military facilities, computing airports, etc.

Where do you use three phase diesel generator and single phase diesel generator?

Single phase diesel generator sets are usually used for low-voltage devices that do not need intensive use. This makes it possible to obtain electricity where there is no grid available, so that small power tools (or similar purposes) can be used.

It can also work as a backup power system for a few hours, as long as it is used for homes or small businesses that are usually powered by a strong grid. This will allow the installation to continue working in the event of a brief failure or disconnection.

However, three-phase diesel generator sets are ideal when supplying power to multiple large single-phase and three-phase loads, because their technology and our rich knowledge of them are usually more reliable, robust and efficient.

Three phase diesel generator sets are used in the worst environment and conditions every day, from being used as a standby power supply for computer systems to military applications. This type of generator supplies critical and emergency loads on five continents around the world.

However, the current trend is to replace single-phase generator sets with three-phase diesel generator sets, coupled with inverter electronic converter that converts three-phase power supply into single-phase power supply. In the medium term, single-phase diesel generators may eventually disappear and be replaced by this equipment, which is cheaper and more reliable. Although it adds electronic grade to the equipment, it is more complex.

In short, each diesel generator set, whether single-phase or three-phase, has its application field, which depends on the technical capacity of each system and the advantages and disadvantages of each technology. If you are preparing to buy diesel generator set, you can find the best high-quality diesel generator set for you.