What Size of Generator is Needed For ESAB Welding?

Table of Contents

If you’re using ESAB welding and cutting equipment, you’re probably wondering what generator should come with it. Essentially, you’re asking what welder generator you should choose, and one of the factors that determine your choice is the size. And while you may think this is such a petty question to ask, it’s actually an important question. The right generator for your welder spells the difference between a good and a bad weld. 

Generator Size for ESAB Welding

You’re probably thinking whether to get a big or small generator for your welding needs. The truth is, we think of size in terms of output, which is measured in watts. You can see the wattage on the model’s specifications, and when you see it, you can derive the amperage. A generator rated at 4800 provides 20 amps at 240 volts or 40 amps at 120 volts. On the other hand, you can convert output ratings in kilovolt-amperes to watts by multiplying the number by 800. For instance, a 10-kVa generator consumes about 8000 watts. 

Basically, you need a generator that can power your machines. There’s no one-size-fits-all choice here. It really depends. A 4000-watt inverter may be able to run a number of ESAB welders. Even a lower rated generator may be able to do the job. For example, the Champion 3400 Dual Fuel Inverter can run many welding machines and is not very noisy. However, you may find large capacity generators quite satisfying. Rated at 9500 watts, the Westinghouse WGen9500DF is probably one of the most reliable ESAB weld generators out there. 

Now, keep in mind that when shopping around for generators, a few deciding factors may be usability and portability. But the often disregarded factor is the power backup, which is essential in areas with erratic power supply. 

The Major Downside of Power Supply from Generators

If you ask professional welders, some of them probably will discourage you from buying generators to power your equipment for a number of reasons. One important reason is the power surges from gensets. Remember that your AC mains delivers electricity with a constant voltage. Under ordinary conditions, AC power comes without sudden fluctuations. Thus, it’s generally safe for your devices, including welding machines. You can work throughout the day without worrying about overloading or circuit breaks. 

Generators are different, particularly the portable ones, which are prone to surges and spikes. Power fluctuations harm welders and affect the quality of your job. This doesn’t mean, however, that generators don’t have a place in welding. Many metal fabrication and car repair shops keep them around because they come handy in certain situations.

Power Requirements

The most important factors to consider when buying a generator for your welder are the input voltage and the output amp, because these determine the wattage or power requirements of the device. Most welders that can do TIG, MIG, and stick welding require more power than basic welders. 

What’s the lowest possible wattage for generators for ESAB weld? Generally, you need a generator that has a higher power rating than your welder’s wattage. This way, your unit is protected from power fluctuations and overloading. 

A welding machine whose power requirement is less than 3000 watts can run using a generator rated anywhere from 3000 to 5000 watts. On the other hand, you need a 5000W generator to power a welder with a wattage between 3000 and 5000. Consequently, you need a generator whose rating is higher than 5000W if your welding machine’s wattage is higher than 5000.

If the welder doesn’t have its wattage specified on the label, you can calculate for it by multiplying the input voltage by the output amp (as mentioned earlier). So a welder requiring 120V with output of 25 amps has a wattage of 3000W. Any generator with a power greater than 3000W can operate that welding machine. 

What about inverter welders?

Inverter welders, on the other hand, have higher power requirements, about 1.5 their wattage. In addition, they require higher quality power. These machines have more stable output than traditional transformer-based welders. Thanks to their advanced electronics (i.e. capacitors). These types of welders need clean power, though. 

The problem is that many generators produce dirty power, which comes with voltage fluctuations. Significant fluctuations or harmonic distortions damage sensitive electronics and cut the lifespan of your machine. You want a generator with low THD (Total Harmonic Distortion) value for your inverter welder. This type of generator produces power without huge spikes and surges. Even newer inverter-style welders with sophisticated transistors still need clean power from generators with less than 6% THD. 

Other Considerations

Before you buy a generator, make sure it produces at least 25% more watts than your welding machine needs. Keep in mind that a generator running at 50% capacity deals with fluctuations more effectively than a generator running near its full capacity. This implies that you’re better off investing in a big generator. Small generators are notorious for their load fluctuations or frequency spikes, which make welding a frustrating, if not an annoying, experience. 

Bottom Line 

To wrap things up, your welder’s wattage determines which generator you should pick. Ideally, you’re looking for 30-50% extra capacity than your equipment needs, especially if you’re using an inverter-style welder. Then again, there are other determining factors, such as price and portability.

Esab Welder Review

We consider Esab to be one of the leading brands when it comes to all things welding. We have written an honesty and comprehensive Esab Welder Review that is a must read if you are considering purchasing one of their machines.

Sam Cobb

Sam Cobb

Chief Editor

Hi everyone, my name is Samuel but all of my friends call me Sam. I have been a very hands on person ever since I was a kid. Back in those days I was more interested in wood work and have always been a very keen gardener. I find physical projects very rewarding and love having something practical that I can use that I have made with my own hands.

As I have progressed with my DIY skill set I have focused more and more on working with metal. Now my favorite projects are combining my metal working skills with my wood working skills.

Our Recommendation