Guide

Selection assistance: Power generator

How often and for what will the generator be used?

The question of how often the generator will be used should be fairly easy to answer (once a year, daily, etc.). As our generators are very robust and reliable, they can all withstand a high frequency of use. What is more interesting is how long it takes to work with the power generator. For a longer running time, a correspondingly large tank should be considered. If you want to use the power unit for gardening, camping holidays or on a construction site in a residential area, sound pressure and possibly the weight are important criteria. The noise limit is currently around 95 dB(A). If sensitive devices such as laptops or televisions are to be operated, we recommend an Inverter-generator , which produces electricity at a constant frequency.

What power is required - starting current

Basically, you add up the power of the individual devices that are to be operated simultaneously. Some devices require more power/starting current during start-up than during actual operation. Therefore, a different multiplication coefficient is applied to the specified power in each case, which you can find in the following table.

 

Device/consumer

Performance

Coefficient

Power unit

Vibrating needle

2.300 W

2

4.800 W

Industrial Vacuum Cleaner

1.800 W

1,2

2.160 W

Concrete mixer

850 W

3,5

2.975 W

Compressor

3.000 W

2

6.000 W

Crèpe hotplate

4.000 W

1,2

4.800 W

Plaster spraying machine

4.300 W

3,5

15.050 W

Mixer

3.500 W

2

7.000 W

Grinding machine

2.200 W

1,2

2.640 W

Refrigerator

200 W

3,5

700 W

Refrigerated display case

1.500 W

3,5

5.250 W

Freight lift

2.800 W

2

5.600 W

Neon lamp

500 W

3,5

1.750 W

High pressure cleaner

2.500 W

3,5

8.750 W

Drilling machine

800 W

1,2

960 W

Hotplate

6.000 W

1

6.000 W

Oil heating system

500 W

1,2

600 W

Belt sander

1.000 W

1,2

1.200 W

Planer

800 W

1,2

960 W

Grooving cutter

2.000 W

1,2

2.400 W

Circular saw

1.100 W

1,2

1.320 W

The data are indicative and we do not guarantee them. 

 

Example:

You want to power a specific device/household with your generator. So take the coefficient for the appliance and multiply it by the power.
 

What is important and how often is the welding unit used?

Welding units are used for welding and maintenance work. The models we offer are easy to transport and can also be used as a power generator on a temporary basis. For welding - regardless of the electrode to be used - we recommend the use of direct current. For intensive use, you should opt for an economical diesel welding unit. These have a longer running time than comparable gasoline welding units, which are more suitable for sporadic use.

Models from Könner&Söhnen of the KS 10000E series (230V) have the possibility to connect a welding inverter with max. 200A welding arc current, provided that the welding inverter has an efficiency of 85% and an arc voltage of 25V.

 

Schweissgeraet 

 

Emergency power generator - powering a house

The ideal unit should have at least 7 kW so that it can supply the entire household. For an increased safety, the connection with the ATS module is recommended. In terms of consumption, diesel units from Könner&Söhnen, Hahn&Sohn and Pramac are clearly advantageous. 

KS 9200 1/3, KS 13, KS 14, 

Hahn&Sohn HDE 9000 1/3 oder HDE 14000 1/3

PRAMAC PMD 5050S

ks-9200hdes-1_3_atsr_01 ks13-2dew-1_3-atsr-1  Bildschirmfoto 2022-02-24 um 12.41.04Bildschirmfoto 2022-02-24 um 12.44.06

 

CIRCUIT DIAGRAM

Since electricity is involved, a generator must be connected professionally. It is necessary or suitable to have the generator connected to the house grid with an ATS module - see illustration. The generator compatible with the ATS module always bears a designation ATSR, for example KS 9200 HDE ATSR 1/3

schema Schema 2    schema II

 

Do you need a power generator for construction site?

The petrol generators, which can ''cope'' better with the starting current, are suitable for this. From the experience we have gained in recent years and the feedback from our customers, we would recommend the following units: Könner&Söhnen KS 12 (1/3), KS 15 (1/3), Honda EU 70, Hahn&Sohn HGG 22000A3

                                KS-15-1E-1-3-ATSR_web  Bildschirmfoto 2022-02-24 um 16.55.57Bildschirmfoto 2022-02-24 um 20.19.31

 

Now something worth knowing

Inverter:


An inverter works as follows: The petrol engine powers a direct current generator. This produces direct current, which is converted into alternating current in the inverter module. Depending on the speed at which the engine runs, the more amperes and voltage it produces in the direct current component. You have to know that volts times amps equals wattage. In other words, the more output power is needed, the faster the motor has to run, but this increases fuel consumption and the noise level. The inverter component always tries to maintain exactly the 50 Hz and the voltage of 230 V. However, this is not suitable for operating machines. The high starting current destroys the inverter module in the long run. It is rather intended to operate electronic devices.

Now to the synchronous generator:


The generator is constructed like a motor. It has a stator (the coils around the outside) and a rotor (the rotating "part" in the middle). It works as follows: The frequency is determined by the speed of the motor, which, by the way, is always around 52Hz. The voltage is controlled by an electronic module (AVR -> Automatic Volt Control) There is also a coil on the rotor. This is supplied with voltage by the AVR module. The higher the voltage, the higher the output voltage in the socket. If the generator is stressed, the frequency drops slightly and the voltage is readjusted with the AVR module. There are also synchronous generators that are compound controlled. These do not have an AVR module, but a capacitor and a bridge rectifier. In this case, the voltage and frequency are regulated on the basis of the speed. Synchronous generators can usually be recognised by a cos phi of 0.8. They bring a 3-fold starting current. What does that mean? Depending on the load and the motor, a motor requires 3 - 10 times the starting current to start up. A 3KW motor thus requires between 9 and 30 KW for a few milliseconds. An asynchronous generator can provide 3 times the power for a very short time. This means that a 2 KW generator provides 6 KW for a very short time.

Here is something about the asynchronous generator:


These are normal three-phase motors with 3 auxiliary windings. The rotor consists only of a laminated core as in a three-phase motor. The generator is controlled by a 3-phase capacitor. The voltage and frequency depend on the speed of the motor. Under stress, the frequency and the voltage drops. For those who are a little deeper in electrical engineering, I would like to say here that this generator produces virtually no harmonics. The generator is also suitable for skew loads.This means that with a 400v generator, the voltage on the unloaded phases does not increase when one phase is loaded more heavily. This is the case with asynchronous generators. If one phase is loaded more than the others, the voltage of the less loaded phase can rise sharply.

So to summarise again: Inverter generators are fuel-saving and, depending on the load, quiet. But they are not suitable for running devices that have a starting current.

Synchronous generators provide a high starting current. Depending on the design, the voltage is controlled by an AVR module and the frequency by the speed.

The asynchronous generators do not actually provide any starting current. However, they are also available with starting current amplifiers. In this case, they also produce 3 times the starting current. The frequency and voltage are controlled by the speed. They are suitable for unbalanced loads. Thanks to their design, they can be used to operate electronic and hard-to-start devices at the same time without fear of overvoltage.

My personal favourite is definitely the asynchronous generator. But as written, it always depends on the application. The asynchronous is also short-circuit proof... and since it is only controlled by a capacitor, it is actually almost indestructible...

We advise against "cheap" devices, if only because of the often missing safety standards. They cannot maintain either frequency or voltage within a reasonable range, and the windings in the generator are often undersized, so that it burns out. The power specifications are also often completely unrealistic.

So, if you love your electrical devices, please don't skimp on the generator....

Fuel oil in diesel generators:

The question arises again and again whether a diesel generator can also be operated with heating oil. The answer to this question is not so simple. First of all, you have to find out about the difference between diesel and heating oil in order to be able to make a statement. Since 1995, the quality differences between diesel and heating oil have become greater and greater. For example, heating oil contains up to 1000 mg/kg sulphur, while diesel is available in Germany and Austria with a sulphur content of 10 mg/kg throughout the country. Today's engines and downstream exhaust gas purification systems would be permanently damaged by the high sulphur content. However, this would not make any difference for smaller gensets without soot particle filters. Furthermore, a (minimum) cetane number is guaranteed (specified) for diesel, heating oil has no such specification. It can therefore have a cetane number far below the diesel specification, nailing and soot emissions (fine dust) are the result. Water hammer" can also occur in the engine if the fuel oil is too "unwilling to ignite". Even more serious is the lack of specifications that limit the proportion of heavy components in diesel (diesel density, 95% point). The relatively high proportion of heavy components in heoiz oil can lead to increased soot formation.

However, there are engine manufacturers, such as Hatz, who approve some engines for use with heating oil. However, they also say that the engine is not approved for continuous operation with heating oil and can be damaged in the process.

These are the technical aspects, whether the engine would be damaged at all. Then there are the tax aspects. According to the Energy Act, Chapter 1, § 3, Paragraph 1, Nos. 1 and 2, a mobile power generator that is not moved during use may also be operated with fuel oil. This means that as long as the generator is stationary during operation and is not moved, it may be supplied with fuel oil. However, if it is moved during power generation, for example during a carnival procession or similar, it must be fuelled with diesel.

 

What do you have to keep in mind?

First of all, definitely the energy tax law. Is the power generator moved during power generation? Yes -> diesel, No -> heating oil

Find out whether your generator is approved for heating oil, and if so, which heating oil. It is best to write to the manufacturer of your generator.

One last thing: This is purely for information. You alone are responsible for your actions and I would like to remind you once again to inform yourself about the legal situation and the technical background. You are responsible for any damage. The same applies if you act contrary to the law. I assume no liability for this!