Comparison Kraftech KT 6500 W vs Forte FGD 6500EW

The type of fuel that the generator's engine runs on.

— Gasoline. One of the main types of fuel for internal combustion engines. Gasoline generators are usually cheaper than diesel generators, all other things being equal, but they are more expensive to run due to the higher price of gasoline; in addition, they usually have a shorter resource than diesel ones. Therefore, it is believed that gasoline generators are well suited primarily as a backup power source in case of a power outage.

— Diesel. Diesel generators are usually more expensive than their gasoline counterparts; on the other hand, diesel fuel is cheaper than gasoline, so the increased cost may well pay off with regular use. In addition, diesel generators have a longer resource and a larger power range than gasoline ones. This allows them to be used as both backup and main power sources, including at rather "energy-intensive" objects.

— Gas. The advantages of gas-fired generators are relatively low noise levels and low emissions. On the other hand, the use of gas as a fuel is associated with certain difficulties: it is necessary to connect to a gas pipeline or regularly replace special cylinders, the fuel system is especially sensitive to leaks, etc. Therefore, there are relatively few such models produced, and most of them are stationary high power generators, in which the mentioned disa...dvantages are covered by the advantages.

- Gasoline / gas. Models capable of using both types of fuel indicated. This gives the user the opportunity to choose the option that best suits a particular situation, and also reduces the likelihood of being left without fuel at the most inopportune moment; on the other hand, such models are more expensive than single-fuel ones. The technical features of gasoline and gas are described in detail above.

Nominal voltage at the generator output.

— 230 V Standard voltage of a regular household socket. It is widely used in everyday life, and there are many 230 V devices among specialized equipment; the only exception is powerful equipment (mainly from 4-5 kW), for which this voltage is no longer enough. It is 230-volt generators that should be considered by tech looking for a device for backup power supply of a residential premises or a small office.

— 400 V Generators capable of delivering three-phase power with a voltage of 400 V. Such power is extremely rarely used in everyday life, but it may be required for heavy equipment, specialized tools and other similar loads. Generators with an output voltage of 400 V are generally more powerful, heavier, larger, more expensive and more "gluttonous" than 230-volt ones. It is worth specifically looking for such a unit only in cases where the presence of three-phase power is essential.

— 230 and 400 V Combined power supply models — most generators with a three-phase output voltage of 400 V are also equipped with single-phase 230 V sockets. This ensures their universal use both for backup power supply of a home or office, and for performing more resource-intensive tasks (for example, in construction and repair, for autonomous operation of high-power loads, etc.).

— 110 V. Generators with 110...V sockets (or 120 V for certain regions). This voltage is found in household electrical networks in some countries of North and Central America, Japan, Saudi Arabia, and occasionally in Great Britain. It is not recommended to connect 230 V equipment to such sockets (unless otherwise specified in the technical documentation for a specific electrical appliance).

— DC (48 V). Models with one or more DC connectors for powering external devices with direct current. The standard DC socket is round and has a pin in the center, but its depth and diameter may vary. The voltages output to the DC output may vary — in this case, 48 V is implied.

The maximum power output that the generator can provide.

This power is slightly higher than the nominal (see above), but the maximum performance mode can only be maintained for a very short time - otherwise an overload occurs. Therefore, the practical meaning of this characteristic is mainly to describe the efficiency of the generator when working with increased starting currents.

Let us recall that some types of electrical appliances consume several times more power (and, accordingly, power) at the moment of starting than in the normal mode; this is typical mainly for devices with electric motors, such as power tools, refrigerators, etc. However, increased power for such equipment is needed only for a short time, normal operation is restored in literally a few seconds. And you can estimate the starting characteristics by multiplying the nominal power by the so-called starting coefficient. For equipment of the same type, it is more or less the same (1.2 - 1.3 for most power tools, 2 for a microwave oven, 3.5 for an air conditioner, etc.); more detailed data is available in special sources.

Ideally, the maximum power of the generator should be no less than the total peak power of the connected load - that is, the starting power of equipment with a starting factor greater than 1 plus the rated power of all other equipment. This will minimize the likelihood of overloads.

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 type of current supplied by the welding generator to the electrodes during welding.

— Variable (AC). Current with constantly changing polarity — as in ordinary household sockets; however, when welding, higher frequencies are usually used — not 50 – 60 Hz, but on the order of several tens of kilohertz. The key advantage of alternating current is that it does not have a fixed polarity — in other words, it is basically impossible to confuse plus and minus when connecting electrodes. On the other hand, constantly reversing the current direction increases the amount of spatter and reduces the quality of the seam compared to using direct current. As a result, this option is relatively rare and is intended for relatively rough work.

— Permanent (DC). Current having a fixed polarity and constantly flowing in one direction, without changing it. This allows you to achieve a more accurate seam with less spatter than with alternating current; as a consequence, it is direct current that most modern welding generators use. At the same time, when working with such a device, you need to carefully control the polarity of the connection — and, depending on the features of the work, both “direct” (“minus” to the electrode) and “reverse” (“minus” to the material) polarity may be required. In addition, additional circuits are required for direct current, which slightly increases the cost of generators.

The maximum current that the welding generator (see above) is capable of delivering to the electrodes during welding.

For different materials, different thicknesses of the parts to be welded and different types of welding itself, the optimal welding current will also be different; there are special tables that allow you to determine this value. The general rule is this: the maximum generator current must not be lower than the required welding current, otherwise the unit will either work with an overload or not be able to provide the necessary welding efficiency.

The maximum diameter of the welding electrodes that the welding generator can work with (see above).

The thicker the material being processed and the wider the seam, the thicker the electrodes should be used for welding; and a thicker electrode generally implies higher currents. There are special tables that allow you to determine the optimal electrode diameter depending on the type and thickness of the material, type of welding, etc. However, anyway, the thickness of the electrode used should not be higher than the maximum allowable — this is fraught with overloads and breakdowns, and at best the generator is simply will not be able to provide the desired efficiency.

Model name of the engine installed in the generator. Knowing this name, you can, if necessary, find detailed data on the engine and clarify how it meets your requirements. In addition, model data may be needed for some specific tasks, including maintenance and repair.

Note that modern generators are often equipped with branded engines from famous manufacturers: Honda, John Deere, Mitsubishi, Volvo, etc. Such engines are more expensive than similar units from little-known brands, but this is offset by higher quality and/or solid warranty conditions , and in many cases, the ease of finding spare parts and additional documentation (such as manuals for special maintenance and minor repairs).