ALFA IN - development, production, sale and service of Professional Power Generators MEDVED

Medved and ALFA IN welding machines

How to correctly choose a welding machine for an electric power unit or an electric power unit for a welding machine?

This is a complex choice, it is necessary to read the requirements of the welding machine manufacturer and to choose a power generator that matches the performance. As for the MEDVED, we offer the possibility to try out the welding machine and the power unit. Below is the corresponding table for our power generators. For selection, MMA welding is the most demanding for the power generators, so we offer a table of our ALAFA IN welders below. This is not a complete list, but only a selection of our welding machines and power generators. It is important to know whether the power unit will cover the power of the welding machine in full, or if a lower powerful unit is sufficient. We test and have practical experience with welding machines of other manufacturers and can advise you.

We present videos of the power plant on our Facebook and YouTube. Here is the link directly to the test with the welding machine Perun 220 E and ARCTOS 10000 V CCL.

CodeMMA invertersPower [kVA]Number of phasesIn fullWelding Current up to 100A (electrode up to 2.5mm)Welding Current up to 140A (electrode up to 3.2mm)
5.0317Perun 220 E1Arctos 20000ARCTOS 10000ARCTOS 11000
5.0309Perun 160E1
5.0272-1PAN 1617,71Arctos 8000Arctos 5000Arctos 8000
5.0270PEGAS 160 E Smart7,41Arctos 8000Arctos 5000Arctos 8000
5.0255-1PEGAS 202 E PFC7,71Arctos 9000Arctos 5000Arctos 8000
5.0254-1PEGAS 162 E PFC5,21Arctos 8000Arctos 5000Arctos 8000
 TIG DC inverters     
5.0112-1PEGAS 160 T HF7,61ARCTOS 9000 B  
5.0130-1PEGAS 200 T HF8,21ARCTOS 9000 B  
5.0161-1PEGAS 160 T PULSE HF7,41ARCTOS 9000 B  
5.0176Alfin 161 W Welding inverter6,41Arctos 9000Arctos 5000Arctos 8000
5.0177Alfin 171 W MAX Welding inverter6,31Arctos 9000Arctos 5000Arctos 8000
5.0503Alfin 300 T Welding inverter.13,33Grizzli 16000  
 TIG AC/DC inverters     
5.0275Alfin 300 AC/DC Welding inverter.14,63Grizzli 16000  
 Multifunctional inverters     
5.0224-1PEGAS 200 MIG SYN PFC6,41Arctos 9000Arctos 5000Arctos 8000
5.0243-1PEGAS 200 MIG MAN PFC-16,41Arctos 9000Arctos 5000Arctos 8000
 AXE 500 IN,
AXE 400 IN
  GRIZZLI 24000  
5.0159-2PEGAS 40 PLASMA PFC ovo 5,41ARCTOS 9000 Beven with a compressor up to 33A 

How to correctly choose MEDVEDA (power generator)


1. 1 x230V, 3 x 400V or cardan

You need to answer the question of what you will primarily use the generator for, whether it is sufficient

But there’s one more question you can’t ask most of the competition. Do I need it with a motor? Do you need to have an engine or tractor in your fleet that is equipped with a cardan output? If so, M-Watt is the clear choice!

2. What regulation will you need?

If you want to choose the power of the central unit correctly, we need to know quite precisely the input power of your appliance and the type of appliance, especially in terms of requirements for supply voltage fluctuations and the nature of changes in the load of the generator (current surges during start-up or sudden changes in input power during operation).

2.1. AVR regulation If it is an appliance that you know is sensitive to voltage fluctuations (e.g. computer, sensitive medical devices, tools with electronic control of input voltage), you need to choose the type of output voltage regulation of the power plant very carefully here. You will use a generator with an AVR. It is an electronic regulation of the output voltage, which ensures that the fluctuation of the output voltage will be within a tolerance of ± 2% in the entire range (at constant load) up to the nominal power of the generator. (AVR is not needed for PEGAS or ALFIN welding machines with PFC – power factor correction, which are not susceptible to voltage fluctuations, but it is necessary to count on a power reserve of power plants of at least 30%).

2.2. Compound CCL regulation If you need to “spin” an asynchronous motor on a circular saw, a paving cutter, or a compressor, i.e., a device with a difficult start-up, you definitely choose a power generator with a compound transformer. These motors do indeed have a “HARD START”, but the compound transformer ensures that the central unit is able to supply a large starting current, even at the expense of the voltage drop. A lower voltage will not harm the asynchronous motor in any way. Calculate that for your “one kilowatt” motor you need 2 – 4 times its rated power in the short term. PEGAS or ALFIN inverter welding machines with PFC – power factor correction – can be operated without problems on power plants with a compound transformer.

2.3. CCL capacity regulation The last series of appliances are manual tools with commutator motors, for which the output voltage with capacitive regulation is sufficient. The power consumption of the appliance can be up to the maximum rated power of the power plant.

3. Possibilities of protection against dangerous contact with inanimate parts

3.1. Standard The safety of the device due to the possibility of electric shock is ensured by separation – the winding of the alternator is not connected to the ground. 3.2. Optional accessories (electrical switchboard, safety elements, circuit breaker) The current protector ensures safe operation and protects the operator in the event of insulation damage. The RCD disconnects the electrical circuit in the event of a difference in electrical current between the power output of the alternator and the part of the circuit connected to ground behind the RCD output. It is prohibited to connect PE and N onto PEN!!!

4. Selection according to performance and type of powered device

The coefficient determines the approximate multiple of the increase in the “label” power consumption of powered devices, which may occur for a short time during operation, especially during the start-up of the device. Most devices have a coefficient of 1, with the exception of those listed below (the list is not complete, it is only an example).

3Pressure washers
 3.5 – 5Refrigerator
2.5Concrete mixers, manual angle grinders, circular saws
2Machine tools and electric grinders
3Submersible pumps
4Washing machines
3,5 – 5
1.5Taladros, fresadoras, Luces halógenas y fluorescentes
2Shredders, string trimmers, brush cutters, hedge trimmers, mowers and chain saws
The coefficient by which it is necessary to recalculate the required power of the power plant

We will be happy to advise you when choosing a power generator. Alternatively, we will come to test the selected types, as in some cases the correct performance is difficult to determine from the table. These are mainly compressors, complexes with multiple powered devices, servers with UPS, cooling boxes, etc. These are mostly 400V and power from 9-10 kVA and above. In these cases, in agreement with the merchant, the manufacturer ALFA IN a.s. arrives at the agreed date directly to the customer with several types of generators and performs a physical test. For this test, it is necessary for the customer to provide their own worker responsible for connecting the resources. This worker must have the appropriate authorization to enter the customer’s electrical network. The manufacturer will supply generators and a technician to operate them for testing. However, he does not have the right to interfere with the electrical installation. In the Czech Republic and Slovakia, we perform these performance tests approximately 1-2 weeks after the first contact.

If the above conditions are met, the manufacturer ALFA IN a.s. make tests free of charge and without obligation as a service to the customer.

Power generators and automatic starts

We present automatic starts for our generators. From simple PDM to iGen.

Choosing a generator is a complex matter. If it is to serve as a backup source, it is even more difficult. Check out our quick video overview.

Presentation AT 207, iGen, PDM

ALFA IN a.s. THE LEADER of the Vysočina region

Our company won 1st place in the prestigious “CZECH LEADER 2020” award in the Vysočina region.

We became the winners of the ČESKÝ LÍDR 2020 competition for the Vysočina region. Here is a link to the video of the announcement, which unfortunately had to take place only online due to the corona virus epidemic without direct participation and meeting with the individual leaders.

We are happy to be part of the BUILDING A PROUD Czechia project

The result of Czech leaders in 2020 in the Vysočina region

Silent inverter power generator

Today, April 26, 2022, there has been a power outage in the Třebíč area since the morning, where the Sonepar electrical materials wholesaler is also located.

In order not to interrupt operations, we have rented a quiet Q6500 QuietPower inverter generator for the site, which has been running since the morning. We honestly tested the generators to make the right choice before the supply was interrupted. It goes without saying that MEDVED power plants work:

Our physical on-site test verified that the power of the Q6500 generator is also sufficient for other important things such as:

The Q6500 QuitPower power generator from Briggs & Stratton, which we equip with sockets according to the valid ČSN standards for the Czech Republic, demonstrated sufficient power, which the power plant can adjust itself according to the current consumption requirements, and relative silence during morning operation in a populated area.

Further information about our power plants is available at and the Alfa In a.s. product catalog. it is at We also respond to user links and simply describe them in the section Don’t you understand technical terms?

Medved #1 and Karel 3

We are going full power. MEDVED power generators help with the production of electricity during blackouts and as backup sources when supply is interrupted. The first MEDVEDAR Karel is also involved

MEDVED generator

SIMUS Generator by Gas

Generators, where the fuel is natural gas, propane butane, solve the problem of bad gasoline, which does not last for a long time. They can be connected to gas distribution lines, either standard natural gas, propane-butane cylinders or from a storage tank located near the building. We are able to connect our automatics to these power stations, which can automatically start the generator in the event of a power outage or when the batteries drop below the set values and supply the necessary energy to keep the facility running. Schematic representation of common electricity supplies

Standardní dodávky elektrické energie.

In the event of a blackout, the AT 207 automation can supply electricity instead

Výpadel elektrické energie

The AT 207 automation can respond to a specific signal, similarly to the PDM automation.

Starts the generator and sends an SMS e.g.:

In the case of a tank with fuel monitoring, it can send an information SMS about the fuel level.

The advantage of gas engines is that there is no degradation in the fuel, and in the case of natural gas brought into the house, then there is no need to top up because it is still available even when the electricity is not working.

VANGUARD gas engine
Vanguard gas engine by BRIGGS & Stratton

The disadvantage of gas engines is less performance compared to gasoline engines and also the differences in performance between natural gas and propane butane.

All the best in 2022

The year 2022 has begun and the beautiful sunny, albeit frosty, weather has made it possible to prepare for testing the generator produced at the beginning of the year in the fresh air. Then goes to the rehearsal room warmed up and ready. A short test in freezing weather will check their reliability even at the first start. Every generator, not only the single-phase ARCTOS and the three-phase GRIZZLI, that leaves us is tested and passed an intense inspection. We also check special M-WATT and WELDVED generator with a welding machine. Sample generators also undergo a demanding measurement with a printout, but more on that next time.

MEDVED generators, PERUN, PEGAS and SVAROG plasmas and INAIRCOM compressors

We continue to test our plasma and generator. This time in cooperation with the Czech compressor manufacturer Inaircom s.r.o. It is a Czech manufacturer with a service background and a supplier of not only compressors, but also related accessories.

This time we chose


We wanted to thank our business partners not only from the Czech Republic, but also from Austria and Denmark, for allowing us to delay the deliveries of the power plants and to be able to take everything that was produced by Friday 25 June 2021 to the affected parts of Moravia hit by the tornado, to the municipalities around Břeclavi and Hodonína. There are also generators for the Mechanik company, which similarly head to Břeclavi. We will try to make up for the delay in production, but we are very happy that we can contribute to the faster recovery of our beautiful country with our little help. Selected generators from our partner J-Rival from Hodonína, Mr. Lukovský, will be designated as a gift to specific municipalities. The generators managed to be delivered to the site on Friday evening, so they are already helping to charge phones, turn on pumps and other work tools.