Input performance
The amount of air that the compressor is able to process per unit of time; usually stated in liters per minute. Performance, along with pressure (see below), is one of the most important parameters: it is it that primarily determines how compatible the compressor will be with one or another pneumatic tool.
It is worth choosing a model according to this indicator in such a way that it can be guaranteed to “pull out” all the tools that can be connected at the same time. Air consumption is usually directly indicated in the characteristics of each tool, and it is quite simple to calculate the total requirement. However, due to the design features, the compressor must have a certain performance margin; the specific value of this stock depends on a number of nuances.
The main point is that some companies indicate for their units the performance at the outlet (how much air is supplied to the tool), while others indicate at the inlet (how much air the compressor sucks in). Since no compressor is perfect, part of the air is inevitably lost during the compression process, so the amount of air at the outlet will always be less than at the inlet. Accordingly, if the output performance is indicated in the characteristics, a margin of 10-20% is recommended, and if the input is 35-40%.
There are also more complex techniques that allow you to more accurately derive the required performance depending on the characteristics of specific tools; they can be found in...special sources.
Power source
Among the power sources in compressors are found,
power grid,
batteries,
gasoline and
diesel. There is a different section for classic car compressors, but there are also solid
compressors powered by 12 V. More details about each of them:
—
Power supply (230 V). The most popular power source used in modern compressors. Electric motors are relatively small in size and weight, and during operation they create much less noise than internal combustion engines and do not produce exhaust gases, due to which they are safe even with poor ventilation in the room. In addition, they are easy to operate, requiring no refuelling, expensive starting equipment or complex procedures. Of the significant drawbacks, it is worth noting, perhaps, the need for an external power source — if it is impossible to connect electricity, a compressor with an electric motor will be absolutely useless. Power supply from a 230 V AC single-phase type limits models in terms of power and such devices can be attributed more to household than to professional ones.
—
Power supply (400 V). Powered by a three-phase (three pairs of contacts "zero" — "phase") network with a voltage of 400 V. Such a network can be conditionally called "industrial": it is not used in everyd
...ay life, but it is widely used in industrial premises such as workshops, workshops, car repair boxes etc. The main advantage of this type of power supply is high power, which allows you to create compressors with high pressure and performance. At the same time, it makes no sense to produce low-power units only for 3 phases — the main advantage is lost, and the disadvantage in the form of incompatibility with 230 V networks (and, accordingly, a limited scope) remains. The 400 V supply is therefore exclusively reserved for high power compressors intended for professional use. Before buying such a device, you must make sure that there is a three-phase connection at the place of the planned installation.
— Battery. Powered by own battery. The main advantages of this option are mobility, the ability to work independently of sockets and the absence of a power cord that can interfere with work. On the other hand, such a power supply is not suitable for high power, a cordless tool, all other things being equal, turns out to be noticeably heavier and more expensive than a mains one, and the operating time is limited by the battery charge. However, in most cases, the battery is made removable, which allows you to keep several batteries ready and change them as needed.
— Gasoline. An internal combustion engine (ICE) that uses gasoline as fuel. Such compressors are indispensable if you have to work in places without access to electricity: gasoline engines do not depend on external power sources, are completely autonomous and can work as long as there is fuel in the tank. On the other hand, they are more expensive than electric ones (both by themselves and in operation, due to the high cost of gasoline), weigh more, make more noise, are difficult to start and require certain maintenance skills. In addition, exhaust gases create serious inconvenience and limit the use of internal combustion engines — when working in rooms, good ventilation is necessary. As a result of all this, compressors with gasoline engines are more of a fallback option in case it is impossible to use an electric motor, and they are not widely used.
— Diesel. Internal combustion engine running on diesel fuel. It is characterized by all the same basic features as for gasoline (see above), but there are some differences. The most striking is that diesel engines are generally more expensive than gasoline engines, but they have a longer resource and are cheaper to operate due to the relatively low price of fuel.
— Power supply 12 V. The ability of the compressor to connect to the car's network as a power supply.Noise level
The maximum noise level produced by the compressor during operation. When evaluating it, it must be taken into account that the decibel used to evaluate noise is not an absolute value. In fact, this means that noises, for example, 20 dB and 40 dB differ in level not by a factor of 2, but by 100 — it is this multiplicity that corresponds to a difference of 20 dB; a twofold increase corresponds to a 3 dB increase. Therefore, to assess noise levels, it is worth referring primarily to comparative tables. For values found in modern compressors, this table would look something like this:
70 dB — loud conversations at a distance of about 1 m;
75 dB — scream;
80 dB — motorcycle engine with silencer;
85 dB — loud scream;
90 dB — freight train car at a distance of 5-7 m;
95 dB — noise inside the subway car.
Anyway, the lower the level of noise produced by the unit, the more comfortable its use, the less it will “hit on the ears” and increase the volume of the entire set of working instruments.
Noise level (LPA)
The sound pressure level in decibels at a certain distance between the noise source and the ear of the compressor equipment operator. Since people do not work in the immediate vicinity of the compressor, the parameter will be useful for estimating the noise level at a distance. It is most often measured at a distance of 7 m from a working installation, less often at a distance of 1 m.
