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Comparison GRAD Tools 5710935 vs Sigma 5710401

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GRAD Tools 5710935
Sigma 5710401
GRAD Tools 5710935Sigma 5710401
Outdated ProductOutdated Product
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Fuelpetrolpetrol
Output voltage230 B230 B
Rated power3 kW2.8 kW
Max. power3.3 kW3 kW
Alternatorsynchronoussynchronous
Alternator windingcopper
Engine
ICE type4-stroke4-stroke
Engine size212 cm³212 cm³
Power7.5 hp7 hp
Launch typemanualmanual
Fuel consumption1.5 L/h1.88 L/h
Fuel consumption360 g/kW·h360 g/kW·h
Fuel tank volume15 L15 L
Fuel level indicator
Continuous operation time10 h8 h
Motor coolingairair
Connection
Number of sockets (230/400 V)22
Sockets 230 V16 A x216 A x2
Output 12 Vterminalsterminals
Features
Functions
automatic voltage regulator (AVR)
voltmeter
automatic voltage regulator (AVR)
voltmeter
General
Sound level (7 m)72 dB72 dB
Dimensions610x460x510 mm610x470x490 mm
Weight43 kg46 kg
Added to E-Catalogfebruary 2023august 2021

Rated power

The rated power of the generator is the highest power supply that the unit is capable of delivering without problems for an unlimited time. In the “weakest” models this figure is less than 1 kW, in the most powerful – 50 – 100 kW or even more ; and generators with welding capabilities (see below) typically have power ratings ranging from 1 – 2 kW to 8 – 10 kW.

The main rule of choice in this case is this: the rated power must not be lower than the total power consumption of the entire connected load. Otherwise, the generator simply will not be able to produce a sufficient amount of energy, or it 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, you need to take into account that only the active power of various equipment is usually indicated in watts; In addition, many AC electrical appliances consume reactive power (the "waste" power consumed by coils and capacitors when operating at that power). And the actual load on the generator depends precisely 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 supply of devices in which the starting power (and, accordingly, the power consumption at the moment of switching on) is significantly higher than the rated 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 one type of equipment it is more or less the same - for example, 1.2 - 1.3 for most power tools, 2 for a microwave, 3.5 for an air conditioner, etc.; More detailed data is available in special sources. Starting characteristics of the load are necessary, first of all, to assess the required maximum power of the generator (see below) - however, this power is not always given in the characteristics; often the manufacturer indicates only the rated 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, and not the rated power.

Also note that if there are several outlets, the specific division of the total power among 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”).

Max. power

The maximum power supply that the generator can provide.

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

Let us remind you that some types of electrical appliances at the moment of startup consume many times more power (and, accordingly, power) than in 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 just a few seconds. And you can evaluate the starting characteristics by multiplying the rated power by the so-called starting coefficient. For one type of equipment it is more or less the same (1.2 - 1.3 for most power tools, 2 for a microwave, 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 lower than the total peak power of the connected load - that is, the starting power of equipment with a starting factor above 1 plus the rated power of all other equipment. This will minimize the likelihood of overloads.

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.

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.

Fuel consumption

Fuel consumption of a gasoline or diesel generator, and for combined models — when using gasoline (see "Fuel").

A more powerful engine inevitably means more fuel consumption; however, models with the same engine power may differ in this indicator. In such cases, it is worth considering that a model with a lower flow rate usually costs more, but this difference can quickly pay off, especially with regular use. In addition, knowing the fuel consumption and tank volume, you can determine how long one refueling will last; at the same time, in inverter models at partial load, the actual operating time may be noticeably higher than the theoretical one, see "Alternator" for details.

Continuous operation time

The time during which the generator is guaranteed to operate without interruption.

This parameter is indicated exclusively for liquid fuel models with a built-in tank, and according to the simplest formula: tank capacity divided by fuel consumption. However, in some models, data may be provided for a certain load level (which is specified in the notes); at a higher or lower load, the operating time will be shorter or longer, respectively. As for specific numbers, in most modern generators the operating time is up to 8 hours - this is quite enough for backup power and occasional use. More reputable models are capable of working for 8 – 12 hours, and an indicator of 13 hours and above is typical mainly for professional solutions.

We also note that, theoretically, many generators can be refueled without shutting down, but in practice it is better to take breaks and not exceed the stated time of continuous operation - this will avoid overheating and increased wear.

Weight

The total weight of the unit - as a rule, excluding fuel; The full fill weight can be easily determined by knowing the tank capacity.

In general, more powerful generators inevitably turn out to be heavier, but models with similar characteristics can differ noticeably in weight. When assessing these differences and generally choosing an option based on weight, it is worth taking into account the specific application of the generator. So, if the device will often 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 much attention to this parameter - or even the opposite: choose a heavier (and, as a rule, more advanced and functional) option.

Regarding specific numbers, it is worth noting that modern generators in general are quite massive. So, a small weight for such equipment is considered not only up to 20 kg, but even 20 – 30 kg ; Many units weigh 150–200 kg, or even more, and the weight of stationary industrial models is already measured in tons.
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