Comparison Sigma 5710831 vs Volt Polska HEXA-GEN 3500

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.

— 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.

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.

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.

Fuel consumption of a petrol or diesel generator when operating at half power, and for combined models when using petrol (see “Fuel”).

Fuel consumption usually increases with load. However, generator efficiency is not always linear - fuel consumption may vary disproportionately with different loads. In this case, the approximate amount of fuel consumed by the generator when operating at half power (50% of the rated power) is given. Knowing the fuel consumption and tank capacity, you can at least estimate how long one fill-up will last.

The volume of the fuel tank installed in the generator.

Knowing the fuel consumption (see above) and the capacity of the tank, you can calculate the operating time on one gas station (if it is not indicated in the specifications). However, a more capacious tank is also more bulky. Therefore, manufacturers choose tanks based on the general level and "voracity" of the generator — in order to provide an acceptable operating time without a significant increase in size and weight. So in general, this parameter is more of a reference than practically significant.

As for the numbers, in low-power models, tanks are installed for 5 – 10 liters, or even less ; in heavy professional equipment, this figure can exceed 50 liters.

— 12V output. The presence of an output with direct power and voltage of 12 V in the generator. The main purpose of this output is to charge car batteries, as well as to power devices originally intended for cars (recall that 12 V is the standard voltage of on-board networks in passenger cars).

— USB charging port . The presence of a USB connector (one or more) on the generator for charging various devices. Most modern smartphones and tablets can be charged via USB, and this charging method is also found in many other devices — from cameras and flashlights to electric screwdrivers and radio-controlled models. The standard supply voltage through this connector is 5 V, but the power may be different, it should be specified separately.

— Smartphone control. Synchronization with a smartphone allows you to control the generator remotely. Thanks to this, the user does not need to approach the device to, for example, start or stop it. Additionally, synchronization with a smartphone allows you to monitor the parameters of the generated electric power remotely and in real time. On the other hand, this will require a constant connection to the Internet and specialized software that must be installed on the smartphone.

— Autostart (ATS). A function that allows the generator to turn on automatically under certain conditio...ns, without any action from the user. Autostart is mainly used when using the generator as a backup power source: while the main power is working, the unit is turned off, and if the voltage in the network disappears, ATS starts the engine, and power to the load begins to flow from the generator. Note that the presence of autostart is indicated only if the generator is initially equipped with an ATS electronic unit; models with the ability to connect such a unit are placed in a separate category (see below).

— ATS socket. A connector that allows you to connect an external autostart unit (ATS) to the generator; the unit itself is not included in the kit. For more information on autostart, see above; here we note that some users do not initially need this function, but may need it in the future — for example, if the generator is initially used for building a house, and then it is planned to be installed in the same house as a backup power source. In such situations, this configuration option will be optimal: when buying the generator itself, you will not have to overpay for the ATS unit, and later, if necessary, you can buy and connect such a unit separately.

— Automatic voltage regulator (AVR). An automatic regulator that allows maintaining a constant voltage level at the generator output. Such a regulator smooths out the differences that occur due to changes in the engine speed; this is especially important when connecting devices that are sensitive to power supply stability. It is worth noting that the presence of an AVR is almost mandatory for synchronous generators (see "Alternator"), but in other varieties this function is not found: in asynchronous and duplex units it is not applicable in principle, and in inverter units the role of the regulator is played by the inverter itself, and they do not require additional electronics.

— Display. A dedicated display mounted on the generator body. Typically, this is a simple LCD screen capable of displaying only numbers and some special symbols. However, even such a screen can display various useful information: voltage, frequency, engine hour meter data, low fuel warning, error code failure messages, etc. This makes control more convenient and visual.

— Hour metre. A device that counts the total time that the generator engine has been running since it was first turned on. This helps determine the overall wear of the engine and the need for repair/replacement, which can be useful both during long-term use of the device and, for example, to assess the quality of the product when buying a used generator. It is usually impossible to reset the hour meter without serious intervention in the design of the device.

— Voltmeter. A device that displays the power voltage produced by the generator. The voltmeter can be made in the form of a separate pointer scale, or its readings can be displayed on the generator's own display (see above). In any case, this function allows you to carefully monitor the unit's operating mode and reduces the risk that an unacceptable voltage will be applied to the load.

— Parallel connection. The presence of special connectors in the generator design, through which two or more units can be connected to a single electrical network (usually with the help of an additional device). This type of connection is used when one unit is not able to handle the entire load and the connection power exceeds the capabilities of the device itself. Also, such a scheme has gained popularity if one of the units is planned to be used as a backup power source.

— Remote start. The remote control generator is included in the delivery set. It is made in the form of a wireless key fob and allows you to turn on/off the device remotely without approaching it.

The electric generator has wheels for moving from place to place. Most often, the design provides for a pair of wheels and a pair of parking supports: during working hours, the supports play the role of brakes, and when moving, they need to be raised above the ground and the generator rolled on two wheels; however, there are models on 4 wheels. Anyway, this feature greatly simplifies transportation: it is much easier to roll the unit than to carry it on weight. This is especially true in light of the fact that the weight of a modern generator can exceed 100 kg: several people will be needed to carry such a weight, while wheels often make it possible to manage by one person.

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.