# We purchase an electric generator. Is it that simple

## Recommendation points

Dreams of energy independence at this time are no longer something distant and unrealizable. Buying a generator is as simple as any other construction tool – the choice of this equipment is so wide that many potential buyers are simply lost in all this diversity. Is it so difficult to choose a generator for your own needs??

## Generator for continuous operation or emergency power supply

Low-power generators are used equally often by both construction and repair crews and individuals. In the first case, the generator will be the main source of electricity at the site, and in the private sector it will play the role of an emergency power source. Just do not consider generators as an alternative to standard power sources – this is an extremely expensive pleasure, the cost of 1 kW of electricity is very high. Even on a construction site, generators are most often used only at the first stage, before the power line is supplied. However, an important condition for this kind of equipment is sufficient power, operating time and engine hours, or rather, the generator resource..

## Let’s deal with the generator power

When choosing a generator, any consumer, first of all, pays attention to such an indicator as power, completely forgetting that there is not only a division into 1-phase and 3-phase generators of different power, but also a number of other characteristics that should be taken into account. First of all, you need to know that manufacturers in most cases indicate the maximum parameters of their product (in this case, power). You can get this result from the generator only for a short period of time. If we draw an analogy with a car, then you very rarely operate a car at its peak, driving the tachometer needle into the red zone of the scale. In order to determine the real capabilities of the generator, you first of all find such a parameter as the power factor, or, as it is often indicated in the technical documentation for the product, cos ?.

If you do not find this parameter, do not be lazy, ask the seller for it. Some manufacturers deliberately do not indicate such data in order to pass off their product as more powerful. Here’s a simple calculation. The generator generates 5 kVA, the generator power factor (cos?) Is 0.8. Realistically, what you can get from your generator is 4 kW. Some manufacturers indicate on their products the power factor, which is equal to unity, and at the same time indicate the real output power of the power plant. So that you do not have any difficulties, we will immediately explain what the values ​​that are found in the technical characteristics, such as kVA and kW, mean:

• VA is kilovolt-amperes. This is the so-called total power (active and reactive)
• kW is kilowatts. This indicator is important to us at the time of choosing a generator, since it shows the active power.
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Cosine phi (cos?) Equal to 0.8 is most often indicated on European products. It is accepted in European standards that the product can operate at full load no more than 10% of the time (for example, no more than 2 hours in 24 hours of continuous operation). The Japanese have slightly different standards. They admit that the product can be overloaded no more than 1.5% of the working time. For this reason, the difference in cosine phi for European and Japanese generators will be quite large..

Let’s take a look at this on the example of specific products: the Makita EG 410 C gasoline generator and the Glendale GP4000L-GEE gasoline generator with a battery. The parameters of these generators are approximately the same. In both cases, 4 stroke, 1 cylinder, overhead valve, air cooled engines are used. Both generators are single phase. There are only differences in the volume of the fuel tank and the way the engine is started. If the Makita EG 410 C generator costs about 28,000 rubles, it has a 5.6 liter fuel tank. and manual start, the Glendale GP4000L-GEE electric generator costs about 30,000 rubles, has a 25-liter tank. and in addition to manual start, it is additionally equipped with an electric starter, which operates from a battery. But after reading carefully again all the data that is indicated on the products, you can think about.

Makita values ​​its long-standing reputation for quality tools and equipment. The generator has two parameters:

• Maximum power 4.1 kW (not kVA, as it should actually be);
• Rated power 3.5 kW.

Accordingly, the power factor of the generator will be approximately 0.85.

The documentation for the Glendale GP4000L-GEE generator does not indicate exactly what the power rating of the product is. However, it is doubtful that the declared capacity of 3.8 kVA / kW corresponds to reality. Especially if you read the model name carefully. Most likely, the real rated power of this product will be about 3.2 kW. Apparently, the manufacturer simply indicated a slightly overestimated rated power of the generator. And yet, you need to give the manufacturer credit that this power is not listed as nominal..

A reasonable question arises – why do we need to know such technical subtleties? The answer is very simple. We considered above rather powerful generators, which, moreover, are far from cheap products. Some consumers (this fully applies both to those who use generators professionally and to those who purchase a generator for the home) naively believe that it will be enough to purchase a generator of the same power as the equipment that is planned to be connected to it. This is where one of the biggest mistakes lies..

## How to choose the right generator for specific equipment

Let’s try to find a generator for “home” purposes. First of all, we need to define a list of those devices that will be connected to our generator. This is necessary in order to know exactly what loads will “fall on the shoulders” of our generator.

Naturally, the first in this row will be light bulbs, which can be classified as active load. This type of load includes electric ovens, heaters (without fans), kettles. Fans, air conditioners, pumps, power tools, vacuum cleaners and many other consumers, which are based on an electric motor, refer to a load with an inductive component (inductive load or reactive load).

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If you need several bulbs to shine in the room and an oil heater to work, then to select a generator, you will only need to calculate the total power of these active consumers. For example. The house will be lit by 5 bulbs of 100 W each, a 1 kW heater and an electric oven with a power of 1.5 kW will work. For these consumers, a 3 kW power plant will be enough for you (the total capacity of all active electricity consumers). But then certain difficulties begin. If a small generator can easily provide you with electricity for light bulbs, then it simply cannot cope with a vacuum cleaner..

The fact is that the vacuum cleaners are equipped with sufficiently powerful electric motors, for which an amendment must be taken into account when selecting a generator of appropriate power. This correction is about 1.25. It is also worth considering the power factor of the generator itself. If you take the same Glendale GP4000L-GEE generator, then you won’t have any problems with bulbs, but with a vacuum cleaner … Let’s just count. The power of a good vacuum cleaner is about 1.8 kW, as we wrote above, the correction is 1.25. This means that for the normal operation of this consumer, 2.25 kVA is needed. Taking into account the coefficient of the power plant itself, we find that for the normal operation of the vacuum cleaner we need a power plant, which has a nominal power of about 2.8 kW. Only in this case all products will work without overload. However, it would be a big mistake to connect any other consumer of electricity to this generator. The Glendale GP4000L-GEE generator will allow you to use a vacuum cleaner and several other active consumers of electricity.

Here are the correction factors for some types of tools and household appliances:

• an electric drill with a power of 750 W has a coefficient of 1.2;
• home woodworking machine with a power of 2.3 kW coefficient of 1.3;
• water booster pump with a capacity of 850 W, coefficient 1.25;
• concrete mixer with a power of 900 W coefficient of 3.5;
• refrigerator with a capacity of 500 W coefficient 3.2.

So it turns out that it is not so easy to choose a generator, knowing only the power of electricity consumers and the power of the product itself. If the Seller does not have such information about the generator that is trying to sell, it is better to choose another place to buy..

## Electric generator device

The generator device is quite simple. All manufacturers produce their products that are very similar to one another: a metal frame or base on which the engine and generator are mounted on special shock absorbers (most often rubber). Engines use either diesel or gasoline. Recently, electric generators have appeared that run on gas. When choosing a generator, pay special attention to the engine. The most common and highest quality gasoline engines are manufactured by Briggs.&Stratton, Honda, Yamaha, Subaru. It is desirable that the engine has an overhead valve (OHV).

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It is with these engines that power plants are equipped, which are designed for long-term operation, and it is these engines that have a sufficiently large motor resource. It is advisable that your generator is equipped with a starting amplifier. This option allows you to smooth out all loads that arise at the time of starting a powerful consumer of electricity. There are power plants that are equipped with special automation, thanks to which, at the moment of a power outage, your station will start automatically and supply electricity to the consumer’s network. It should be noted that this equipment is quite expensive and a number of technical conditions must be met before installing this generator. For example, a gasoline generator Endress ESE 1206 DHS / A-GT ES ISO currently costs about 183,000 rubles. Agree, not every family budget will make it easy to make such purchases. It is also worth noting that for such products, you may need to allocate or build a separate room, or purchase a special protective cover in order to install the generator on the street. All electric generating installations with internal combustion engines periodically require qualified service..

## Generator manufacturers

With all the simplicity of the design, the production of generators is a rather complicated and laborious process. Recently, a large number of very different generator models from a variety of manufacturers have appeared on the market. But, even if the power plant is equipped with an engine of a well-known manufacturer, this does not mean at all that this is a high quality product. Very often they offer power plants that are equipped with Honda-type engines (as they say in the market). On external examination, in fact, you can catch the similarities. However, similarity does not mean quality at all. And it’s not at all worth talking about the resource of these products. If you listen carefully to the sellers in the market (read – in the bazaar), then you will be offered almost exclusively European products (Belgian, German, French) for almost nothing. Are you not alarmed by the fact that such factories simply do not exist in Europe, and the addresses indicated in the passports for such products are just the addresses of small offices? In fact, all such products have one country of origin – China. There are very few real European and Japanese specialized manufacturers of such equipment and their products are very expensive. But she really is worth the money.

So it turns out that if we decide to purchase a generator that is not a small one, which will provide you with electricity in a country trip to nature, and we want to choose the right power plant that will allow you to fully satisfy all your needs, then you should turn to professional sellers of such equipment for help. Only then will you be sure that your generator and all those consumers that you connect to it will work for a long time and without breakdowns..

Happy choice and safe work.

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