Rated power
The nominal power of a generator is the highest power that the unit can supply without problems for an unlimited period of time. In the “weakest” models, this figure is
< 1 kW, in the most powerful ones –
50–100 kW and even
more ; and generators with welding capabilities (see below) usually have a nominal power from
1–2 kW to
8–10 kW.
The main rule of choice in this case is as follows: the nominal power must not be lower than the total power consumption of the entire connected load. Otherwise, the generator will simply not be able to produce enough energy, or will work with overloads. However, to determine the minimum required generator power, it is not enough to simply add up the number of watts indicated in the characteristics of each connected device - the calculation method is somewhat more complicated. Firstly, it should be taken into account that only the active power of various equipment is usually indicated in watts; in addition, many AC electrical appliances consume reactive power ("useless" power consumed by coils and capacitors when working with such power). And the actual load on the generator depends on the total power (active plus reactive), indicated in volt-amperes. There are special coefficients and formulas for its calculation.
The second nuance is related to the power su
...pply of devices in which the starting power (and, accordingly, the power consumption at the moment of switching on) is significantly higher than the nominal one - these are mainly devices with electric motors such as vacuum cleaners, refrigerators, air conditioners, power tools, etc. You can determine the starting power by multiplying the standard power by the so-called starting coefficient. For equipment of the same type, it is more or less the same - for example, 1.2 - 1.3 for most power tools, 2 for a microwave oven, 3.5 for an air conditioner, etc.; more detailed data can be found in special sources. Starting load characteristics are necessary primarily to assess the required maximum generator power (see below) - however, this power is not always given in the characteristics, often the manufacturer indicates only the nominal power of the unit. In such cases, when calculating for equipment with a starting coefficient of more than 1, it is worth using the starting power, not the nominal power.
Also note that if there are several sockets, the specific division of the total power between them may be different. This point should be clarified separately - in particular, for specific types of sockets (for more details, see "230 V sockets", "400 V sockets").Alternator winding
—
Copper. Copper winding is typical for advanced class generators. The copper alternator is characterized by high conductivity and low resistance. The conductivity of copper is 1.7 times higher than the conductivity of aluminium, such a winding heats up less, and compounds made of this metal endure temperature drops and vibration loads. Among the disadvantages of the copper winding, one can only note the high cost of the alternator. Otherwise, generators with copper winding have high reliability and durability.
— Aluminium. The aluminium winding of the alternator is typical for low-cost-class generators. The main advantages of aluminium are light weight and low price; otherwise, such a winding is usually inferior to copper counterparts. An oxide film is created on the surface of aluminium, it appears everywhere, even in the places of contact soldering. The oxide film undermines the contacts and does not allow the outer protective braid to securely hold the aluminium conductors.
Engine size
The working volume of the engine in a gasoline or diesel generator (see "Fuel"). Theoretically, more volume usually means more power, but in fact, everything is not so clear. Firstly, the specific power strongly depends on the type of fuel, and in gasoline units, also on the type of internal combustion engine (see above). Secondly, similar engines of the same power can have different volumes, and there is a practical point here: with the same power, a larger engine consumes more fuel, but by itself it can cost less.
Sockets 230 V
The number of 230 V sockets provided in the design of the generator, as well as the type of connectors used in such sockets.
The type of connector in this case is indicated by the maximum power that is allowed for the outlet - for example, “2 pieces for 16 A”. The most popular options for 230-volt outlets are
16 A,
32 A, and 63 A. We emphasize that amperes in this designation are not the actual power that the generator can produce, but the outlet’s own limitation; the actual power value is usually noticeably lower. Simply put, if, for example, the generator has a 32 A socket, the output power on it will not reach 32 A; and the specific number of amperes will depend on the rated and maximum power of the unit (see above). So, if for our example we take a rated power of 5 kW and a maximum of 6 kW, then to a 230 V outlet such a generator will be able to produce no more than 5 kW / 230 V = 22.7 A standard and 6 kW / 230 V = 27, 3 A at its peak. And if the power has to be divided between several outlets, then it will accordingly be even less.
As for specific types of connectors, the higher the power permissible for the outlet, the higher the requirements for its reliability and quality of protection. In light of this, as a rule, higher power outlets can be connected to lower power plugs (directly or through an adapter), but not vice versa. And if there are several sockets, by their type it i
...s possible to estimate with some certainty the distribution of the entire power of the generator between them: between two identical sockets such power is usually divided equally, and more power is allocated to an socket with a larger number of amperes and power. However, specific details on this matter should be clarified separately in each case; It's also worth considering 400V outlets, if available (see below).Noise level
The noise level produced by the generator when operating in normal mode. The less noise the unit makes, the more comfortable it is to use, the closer it can be placed to people, but the higher its price, all other things being equal.
It is also worth considering that generators with internal combustion engines are, in principle, quite noisy equipment. Thus, even the "quietest" units produce
< 70 dB - this is the volume of a conversation in tones from medium to high. Accordingly, it is recommended to install the device remotely from the place of use. At the same time, we note that the noise level is not directly related to the power: for example, among units of 80 dB and more, there are both heavy and relatively low-power models.
Sound level (7 m)
Sound pressure level in decibels at a distance of 7 m between the noise source and the ear of the equipment operator. Since people do not work in the immediate vicinity of the generator, the parameter will be useful for estimating the noise level at a distance. For example, current European Union regulations require that the sound power of generating sets with a power of more than 2 kW does not exceed 97 dB — at a distance of 7 m, the noise from the generator engine will correspond to a sound pressure of about 72 dB.
Weight
The total weight of the unit - usually excluding fuel; the weight on full tank can be easily determined knowing the tank capacity.
In general, more powerful generators are inevitably heavier, but models with similar characteristics can differ significantly in weight. When assessing these differences and generally choosing an option based on weight, it is worth considering the specifics of the generator's use. So, if the device is often to be moved from place to place - for example, when used "on the road" - it may be worth paying attention to lighter units that are more convenient to transport. However, it is worth considering that the downside of a lightweight design is often an increased cost or a reduced degree of protection. But for stationary use, you can not pay special attention to this parameter - or even the opposite: choose a heavier (and, as a rule, more advanced and functional) option.
Regarding specific figures, it is worth noting that modern generators are generally quite massive. Thus, a small weight for such equipment is considered not only
< 20 kg, but even
20-30 kg ; many units weigh
150-200 kg, or even
more, and the weight of stationary industrial models is measured in tons.