Alternator
The type of alternator provided in the unit.
The alternator is the part of the generator that is directly responsible for generating electricity. Such a system works on the principle of the movement of wires (coils) in a magnetic field, due to which an electric current arises. However, the features of the work of the alternator can be different, on the basis of which they are divided into types:
asynchronous ,
synchronous,
inverter and
duplexes. Here are the main features of each option:
— Asynchronous. The simplest version of the alternator. The rotor (rotating part) in such models during rotation is somewhat ahead of the movement of the magnetic field created by the stator (fixed part) — hence the name. The practical advantages of asynchronous alternators are simplicity, low cost, good protection from external influences and insensitivity to short circuits and prolonged overloads. The latter makes them the best choice for powering welding machines. In general, asynchronous generators are designed mainly for active loads: lighting devices, computers, electric heaters, etc. For reactive loads (with coils and capacitors), it is better to use synchronous units (see below). It is also worth noting that in an asynchronous alternator, the voltage and frequency of the output current directly depend on the rotation speed; t
...herefore, such devices are particularly demanding on the stability of the drive motor.
— Synchronous. In this type of alternators, the rotation of the rotor and the magnetic field of the stator coincide (unlike asynchronous models). Synchronous generators are somewhat more complex in design and more expensive, they are more sensitive to short circuits and prolonged overloads. On the other hand, such a unit does an excellent job with both resistive and reactive loads: for a short time, it is able to deliver a current many times higher than the rated current, thus providing the necessary starting current for the reactive load. In addition, the design of synchronous generators includes an automatic control unit that outputs a stable voltage and is able to compensate to a certain extent for fluctuations in the speed of the drive motor. However, in terms of voltage stability, synchronous models are still inferior to inverter ones (see below).
— Inverter. Synchronous generator (see above), equipped with an additional electronic unit — an inverter. This block provides double current conversion: from AC to DC and then back to AC. Such devices are not cheap, but they have a number of advantages. Firstly, the output is a very stable current, practically without any jumps and fluctuations. Secondly, the generator is able to regulate the operation of the engine depending on the load: for example, if the load is half of the output power, then the current engine power is halved; this results in significant fuel savings. Thirdly, inverter models are lighter and more compact than traditional generators, and they are less noisy. It is such a generator that is considered the best choice for a load that is sensitive to the quality of the current, such as audio equipment or a TV. At the same time, units of this type have a relatively low power and are not designed for long-term operation or high starting loads, and therefore they are used only as backup power sources for relatively low-power power supply systems. In addition, when choosing an inverter generator, it is worth clarifying the shape of the output signal: not all models give an perfect sine wave — there are also units with a trapezoidal pulse that are not suitable for delicate equipment.
— duplex. Type of alternators developed by Endress and used mainly in generators of this brand (although devices from other manufacturers are also found). According to the creators, such an alternator combines the advantages of synchronous and asynchronous models. So, on the one hand, it is able to withstand high inrush currents without compromising the supply of other consumers, and the design usually has an auto-voltage regulator at the output; on the other hand, most of these generators can also be used to power welding machines, and the number of high-frequency harmonics at the output is very low. The disadvantages of "duplexes", in addition to the high cost, include the need to configure for a specific set of connected devices.Power
The operating power of the engine installed in the generator. Traditionally stated in horsepower; 1 HP approximately equal to 735 watts.
First of all, the rated power of the generator directly depends on this indicator (see above): in principle, it cannot be higher than the engine power, moreover, part of the engine power is spent on heat, friction and other losses. And the smaller the difference between these capacities, the higher the efficiency of the generator and the more economical it is. However high efficiency affects the cost, but this difference can pay off with regular use due to fuel savings.
Protection level
The level of protection provided by the generator housing — namely, the degree of protection of the “hardware” from dust, moisture and foreign objects. It is designated by the IP standard with two numbers, one of which corresponds to protection against solid objects and dust, the second — from moisture, for example, IP24.
According to the level of dust protection (first digit) in modern generators, the following values \u200b\u200bare found:
2 — protection against objects with a diameter of more than 12.5 mm (fingers, etc.);
3 — from objects larger than 2.5 mm (most instruments);
4 — from objects more than 1 mm (almost all tools, most wires);
5 — dustproof (full protection against contact; dust can penetrate inside, but does not affect the operation of the device).
Water protection levels can be as follows:
1 — protection against vertically falling drops of water;
2 — from water drops with a deviation of up to 15 ° from the vertical axis of the device (rain);
3 — from water drops with a deviation of up to 60 ° from the vertical axis of the device (rain with wind);
4 — against splashes from any direction (rain with strong wind);
In general, for indoor use, this indicator does not play a key role, but on the street and in similar conditions (for example, at a construction site), you should make sure that the selected generator is sufficiently protected — or else take additional protection measures.
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.
