Power generators: how to choose the right one

Applications, power requirement and practicality

/ Inspirations


Estimated reading time 5 minutes

A power generator produces its own electricity for running equipment that would otherwise have to be connected to the mains network. It produces its own power thanks to an engine driven by fuel, typically petrol. Gas generators are less common, whereas diesel generators are typically designed for intensive use in various business sectors—industry, construction, agriculture, telecommunications, etc.—and in emergency cases.

Let’s leave aside stationary generators, which offer the best fuel economy and provide power in crisis situations, and instead focus on portable power generators, which you can use for leisure time and work, when you are in isolated areas or places that aren’t (yet) connected to the mains grid. For example, maybe you are travelling in a motorhome or organising a garden party, or you have work to do in the countryside or on a building site, or you are running a craft stall in a market or working as a street vendor. A power generator enables you to cope with power interruptions caused by general power outages, network maintenance, overloads or malfunctions in your household electrical system. Below we discuss what aspects you should consider when choosing a power generator, also known as a generator set or genset.

How power generators work

Power generators operate based on magnetic induction. Without going into too much technical detail, the mechanical energy developed by the engine is converted into electrical energy. Compared with conventional generators, inverter generators stabilise the current in several stages by means of a microprocessor. Generators supply both alternating current, which is the type of electricity you use in the home, and direct current.

A power generator has a functional core consisting of the engine, which is powered by fuel from a tank, and the alternator, plus a number of other electrical and electronic components. It is also equipped with a starting system, control features for turning on and operating the generator (controls, indicator lights, etc.) and sockets for supplying power (single-phase 230 V, three-phase 400 V and USB for alternating current; 12 V for direct current). The structure of the generator can be either open-frame, with a metal frame on the outside, or close-frame, with the components fully contained in an enclosure.

How to choose the generator that's right for you

On the market you can find many types of power generators that differ in terms of engine and power source, output (wattage), voltage and other electrical parameters. Besides the different structures (open or closed frame), other variables are size and weight, noise emission, starting system, transportability and price. With so many parameters to choose from, how do you decide which solution is right for you?

The first step is to estimate how many and what kind of devices you want to power with your generator. Each appliance has a label indicating the maximum power it needs to operate (for more information, check the appliance instruction manual). This rated power must be multiplied by a starting coefficient that takes into account the starting current drawn at turn-on, which is higher than the current needed for continuous operation. By adding together the total power used by the devices that you want to simultaneously connect to the generator, you get the power output required by your generator, which you should then multiply by a safety coefficient (1.20-1.25) to add a margin of 20-25% extra power. This gives you the total output in kilowatts that your generator must have, as a basis for choosing the right model to meet your actual requirements.

Once you have estimated your power needs, you then need to consider the situations in which you will use the generator. We mentioned earlier that diesel generators are intended for intensive and prolonged use at work, on construction sites, for emergencies and so on. By contrast, petrol generators are the best solution for leisure time and all the jobs you want to do at home, in the countryside, in woodland etc. They are also available with multiple power ratings, such as the power generators in the Oleo-Mac catalogue.

As we already saw when calculating the power requirement, the intended use of your generator will depend on the devices you want to run or charge with it, which could be portable or stationary household appliances, electronic devices, work tools or gardening equipment. The power they run off is supplied through sockets of a certain voltage: the standard socket has a 230 V single-phase voltage, like the sockets on your walls at home.

In addition to household voltage, the generator can supply industrial alternating current voltage (400 V) via a three-phase socket, which enables you to operate high-powered tools and machinery such as a welding machine or wood splitter: the PGE 80E-3 DCS 6 kW power generator is one such example. Generators also supply direct current through a 12 V cigarette lighter socket, or an outlet with positive and negative poles. Another type of output, usually found in inverter generators, is a USB port for charging smartphones, tablets and so on.

To ensure that the generator maintains a stable output current, it needs an automatic voltage regulator (AVR), which is a feature on Oleo-Mac's open-frame models: the 3 kW PGE 35 DCS, as well as the 6 kW PGE 65 DCS, PGE 65E DCS and PGE 80E-3 DCS. Alternatively, opt for a generator with inverter technology, such as the PGE 23i S or PGE 48i S. Inverter generators protect against power surges that can potentially damage sensitive electronic devices—smartphones, computers, TVs and so on—and any household appliances equipped with circuit boards.

The power rating of a generator determines numerous other variables, because as the power increases, so do the dimensions of the engine, alternator, fuel tank and all the other components. This in turn affects the generator’s noise emissions, fuel consumption, run time, size and weight, and therefore factors such as operator comfort, practicality and time savings.

Depending on the context, noise emissions may be a more or less important consideration, for example if there are noise regulations or quiet periods to be respected, as in the case of campsites. From this point of view, closed-frame generators with a soundproof body, like the Oleo-Mac PGE 23i S and PGE 48i S inverter generators, are a winning choice. Compactness and weight are key aspects when it comes to the transportability of a power generator, as are the presence of wheels. Likewise, the starting system of the genset—either manual with pull cord or electric with a simple push-button—determines how easy and fast it will be to use.

Among the equipment that you can power and charge with a power generator, we listed gardening tools, which includes both electric and battery-operated equipment such as hedgetrimmers, chainsaws, lawnmowers and brushcutters, as well as blowers and high-pressure washers.

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