What Size Generator Do I Need To Run A Welder?

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Sometimes it’s just more practical to undertake welding work in the field instead of the convenience of your shop. Today’s generators and welders are more powerful and portable, making it easier than ever to weld in remote areas, but what size generator is suitable for you? A welder generator provides welding power without relying on electricity. Just fill the gasoline tank as you would a standard generator, and the welder generator will power your welding equipment anywhere you need it. Welding generators have become vital equipment for construction sites, agriculture, industry, and more.

So, what size generator do I need to run a welder? You can use any welding unit with a wattage of less than 3000W, which is easily operated using a 3000 to 5000W generator. But you will need to make sure that wattage is higher than 3000W. The more powerful model you use, the easy to handle any of the 240V of transformers.

Why Use A Generator For Welding?

Generators are using fuel instead of electricity central. They are considered vital industrial and construction tools. Even farmers use them to construct or repair diverse objects. It works like a standard generator; you have to fill the tank and turn it anywhere you need it.

One of the perks is that it can be used as a stand-alone generator. That means you can use it for other power tools or appliances. It can save long-term space and money.

What Size Generator Do I Need?

What Size Generator Do I Need?

The size you choose depends on the job and locality. For example, industrial parts demand a more significant generator. Generally, you will require a minimum of 30 amps for welding.

Accordingly, the generator size should be raised. If you’re searching for something in between that can handle a bit of everything, there are new sorts of 3-in-1 or 4-in-1 combination generators, sometimes known as “workstation generators.” Available for numerous purposes:

  • Welder
  • Battery charger
  • Generator
  • Compressor

Keep in mind that welding generators differ from regular generators since they are designed to perform with consistent energy load, while the other is not. They offer a constant sine wave for continuous welding flow.

For example, you will need to try power a transformer-type welder; a standard generator may not provide a continuous sine wave or enough amps. You’ll need a welder generator then.

What Size Generator Do I Need To Run A Stick Welder?

You’ll need at least 10kW to run a stick welder,’ however, the Hobart Champion 145 welder/generator only supplies constant 4000 watts. The Lincoln Electric facility requires at least 10kW. Then there are necessary watts = volts * amps, which makes me assume I need only 120 * 220 = 2640 watts, which sounds like a feeble generator. Non-EE perplexing.

The welds I made with my cracker box stick welder on a fence – even at 120 amps on 110v – were lovely as those created with the Bobcat 250 I rented before buying the genny.

I welded cleats on 1/8″ metal posts using 1/8″ E6013 rods at 120A on 110v (primarily because I didn’t have a 220v plug off that generator).

What Size Generator Do I Need To Run A MIG Welder?

If your generator has a maximum output of 5000 watts, it serves you well. Unless it’s more than 5000 watts, you should be okay. Just don’t use it over 75-80% power.

As a rule, a generator is more likely to run a welder if it is an inverter type than a transformer type. Working on specific field initiatives is simply more practical than your shop.

Today’s welders and generators are portable and powerful, making welding remotely more straightforward than ever before.

However, what size generator is optimal for welding purposes? A 5000-watt generator is a powerful unit, but that doesn’t imply running industrial equipment like a welder.

Some industrial generators can provide power, though, and operators should ask their suppliers to work for their specific demands.

Let’s look at this generator’s capability. A 5000-watt generator may power a welder unless the voltage exceeds 240 volts.

If you’re looking for a precise solution, certainly, but generators aren’t for everyone, and you may need to buy more than one unit to keeps your equipment functioning. A generator is a mechanism to power other equipment in an emergency.

What size generator do I need to run an inverter welder?

Some of the most typical questions individuals ask before buying a generator are: how big do I need a generator? What size generator can run a refrigerator and freezer? Could I power the whole house? How many watts to power my MIG welder/sump pump/air compressor?

If you require a home generator, many home appliances demand more incredible energy. Large dual-fuel units like Westinghouse WGen9500DF are the most excellent choice for households.

It’s an RV generator you’re looking for—Champion 3400 Dual Fuel Inverter is an attractive choice. This quiet 3000-watt inverter generator can run everything in your trailer, including AC, refrigerator, TV, and lighting circuits.

Use our generator wattage calculator to estimate how many watts you need.

So my contribution is that in the case of a 120A dual-voltage cracker box stick welder if you have a continuous 7500W generator, you’re gtg! You may get on less but don’t see the need for 10kW for agricultural use.

Practical usage, total portability, and power backup are the three most prominent considerations prompting all welding professionals to consider buying power generators.

At some point, the irregular power supply annoyed amateurs and pros alike. Finding the correct welder generator becomes even more crucial for individuals with job areas beyond state power supply constraints.

We all admit that we need the correct tools, gear, and power source for any endeavor to be successful and enable us to use our capabilities to the maximum. All three demand serious study, thorough investigation, and debates while making our pick.

While our work area determines the choice of the proper equipment, our comfort and utility depend on selecting the appropriate gear. Zeroing on the perfect Genset, however, depends on the welder we aim to power.

If you’re reading this, you’re most likely researching buying a new generator for your welder or may be interested in gaining some knowledge on welder gensets; whatever the case may be, keep reading.

Things to consider

• Consider the Wattage of the Generator

First, search for the generator output. They are usually supplied in watts. The wattage figure is a measurement made by determining what the average voltage equals.

For example, if the generator is 4800 watts, it can give 40 amps at 120 volts and 20 amps at 240 volts.

Your generator should have two output ratings, first the running watts and second the peak watts. Typically, peak wattage is above running watts. Peak watts can also be called start-up watts. This is higher to withstand the transient output spike that occurs when a motor is first started.

• Consider the Wattage of The Stick Welder

Next, figure out the maximum watts the welder will draw. You can either look at the product listing on the internet or the store where you bought it.

It can even state in the owner’s handbook or on the welder itself on the data plate. If not, you will be able to find out the watts using the amperage and voltage data. Use the highest figure—for example, 240 volts and 25 amps.

Multiply these two figures together to get watts. The value supplied is 6000, making the wattage 6000 watts. It’s worth noting that many manufacturers don’t put accurate measurements or may round up or down. Always overestimate our recommendations.

The wattage amount you get for your welder is the least to run. The welder runs at 6000 watts in our case. With this in mind, a generator’s wattage would need to be at least 6000, or more if possible.

• Use the Manufacturer’s Voltage Rating

Some manufacturers use welders at 230, 115, and 110 volts. However, they can power 120 and 240 volts.

The manufacturer’s number U1 is best utilized to evaluate the accuracy of the machine as it is the voltage the firm uses to rate it and establish how much amperage it requires.

• Get the Right Amperage Value

Welders can come in a range of amp ratings or only one.

Look for the electrical device’s I1max rating because it’s the most excellent rated supply current. The I1max number may represent the maximum current drain on the start-up.

By calculating your I-max current with the manufacturer’s voltage rating, the maximum watts required to operate your welding equipment are derived.

While talking about the welder generator, the manufacturer’s minimum recommended surge generator is 6000-watts for 140 STi. In this welder’s owner’s handbook, the manufacturer suggests running the electrical system at 24.2 amps with 240 volts.

I expected the 120V, tiny 240V transformer welders to operate well with the cheap Westinghouse generator. The more powerful type handles 240V transformer welders up to 250 amps.

Usually used to size dedicated building circuits when considering rated duty cycle limits (idle time) and heat build-up. Without making modifications, calculating maximum wattage is too low.

As I noticed from multiple companies, when manufacturers supply both values, the I1max rating is generally more than twice the I1eff rating. A Lincoln 140 data plate, for example, offers an I1 or “suggested circuit breaker” information.

This machine’s I1max rating is likely closer to 25 amps, with 20 amps x 120 volts about 2400 watts. Lincoln recommended a 3000-watt generator for this welder.

While talking about the welder generator, it may be too tiny to compute the circuit breakers maximum wattage for the entire operation. An adequately operated circuit breaker is time-delayed and would probably not travel as a transient 25 amp surge develops. Surge-rated generators have surge values above 2400 watts, causing a concern.

• Traditional Transformer-Based Welders

This heavy-duty source delivers welding power with copper and aluminum transformers that modify AC electricity to low-voltage/high DC power.

Traditional method welders operate well with any generator. They’re reliable, not responding to dirty electricity.

• Inverter-Style Welders

Inverter welders often weigh less than half of typical welders using technology for efficient welding power with significantly smaller transformers. They produce a very stable output thanks to high voltage condensers.

But advanced electronics need input quality

Many generators cause excessive voltage and frequency variations, called “dirty power.” It’s a percentage of Total Harmonic Distortion or THD. Dirty electricity can quickly harm sensitive gadgets or shorten cumulative damage life.

Particularly vulnerable are earlier inverter welders employing Metal-Oxide Field-Effect-Transistor (MOSFET) technology.

New machines based on insulated-gate bipolar transistors (IGBT) fare better but still require 5% or less THD clean power generators.

What to Look For In a Welder Generator?

01. Input voltage protection:

Standard portable generators generate unpredictable sine wave power, generating fluctuations in welding. On the other hand, welder generators provide high-voltage surge prevention measures to prevent high-voltage spikes.

If you need to utilize a regular generator that is not welder-friendly, an inverter welder with built-in voltage protection is recommended. Protection prevents current overload difficulties. It will also reduce the possibility of damage from erratic voltage spikes, creating superior welds.

02. What fuel does it use?

The correct answer is the Engine Driven Welders incorporates gasoline, diesel, or propane-fuelled engine connected with an electrical generator to generate Stick, TIG, MIG, and Flux-Cored welding. Typically, engine-driven welders are moved outside on a truck or trailer. Electricity provided by an engine-driven welder is powered by fans, pumps, air compressors, or other electrical tools often found in jobs.

03. Why is generator power potentially harmful?

Today, most generator sets use digital automated voltage regulators and excitation systems to create steady voltage and handle ‘non-linear’ loads well. Simultaneously, ‘non-linear’ load equipment makers have introduced filters to limit harmonic current distortion. Some establishments also use capacitors to boost power when running on the utility source to avoid higher energy charges. While these scenarios have favorable benefits on the customer’s system, they can cause a generator considerable problem.

AC (mains) supply follows a sine wave pattern. When running equipment with sensitive electronics (such as inverter machines and computers), a power supply with a completely clean sine wave is the safest, but this is almost impossible.

A thoroughly ‘clean’ 240V single-phase AC sine wave looks like:

Mains power is (generally) quite near to perfect sine power; hence it rarely creates problems.

04. Guidelines for generator use with inverter welders:

By following these rules, the operator will minimize the possibility of dangerous voltage spikes and help the welding equipment work fully.

05. The Generator Size:

Determining the correct generator size needed to run welding equipment safely is not always straightforward. Some of the elements to examine are the welder’s current draw ratings, the generator’s rated output and whether this is an accurate rating (sadly, some generators are overrated), whether or not the generator will be utilized to run other power equipment simultaneously, etc.

For suggested generator sizes to run specific Weldclass Weldforce machines, see this website’s instruction manual or product information.

06. Quality generator:

As indicated above, a good quality generator appropriate for driving an inverter should have a low THD (Total Harmonic Distortion) output. All credible suppliers or manufacturers of portable generators can indicate the THD ratings on their products.

Generators with a low THD rating (6% or less) will have ‘relatively’ clean power, making them acceptable for running inverter welders.

A generator with a high THD rating (above 6%) is likely to be a low-quality unit and should not be utilized for inverter welders. See also ‘Tips on buying suitable generators,’ item 6 below.

07. Do and don’t use inverter-welded generators:

Start & Shutdown: Always unplug the power lead from the generator before starting or stopping the generator engine.

Fuel Supply: Always verify the generator engine has a safe fuel supply, and the fuel line is in good condition. The machine should not run out of fuel while connecting the welder to the generator.

Maintenance: Keep the generator in good condition. Don’t utilize a generator needing service or replacement.

Power Extension Leads: Do not use low-quality, repair, or replacement power leads. Use heavy-duty leads—see table below.

08. Can I use a small(er) generator to run my welder?

The recommended minimum generating size is 7kva (for up to 160A welders). We are often asked, “Why can’t I use my 5kva generator to run this welder?”

Other welding equipment providers sometimes indicate that their equipment can be powered by generators as small as 4-5 KVA.

Sure, the welder may run to some extent, but that’s why using smaller generators is NOT a good idea;

As indicated in point 2d above, the generator will have to work considerably more complicated. This will raise the likelihood of significant power spikes that could harm the welder or cause it to shut down regularly.

The welder’s production will be significantly reduced, maybe to the point where the machine has no utility or the operator becomes very frustrating.

Often, the generator will be used to simultaneously operate other equipment (e.g., power tools), which will compound the initial concerns.

Although a more significant generator may cost more initially, an adequately sized (or over-sized) generator will allow you to get the job done right the first time… and considerably lower your welder’s risk of costly damage. And who regrets ‘too much’ performance?

Here’s another way to look at it; let’s assume you buy a car for a trailer. Would you buy a car that only has adequate power and must constantly operate near “red line” rpm to complete the job? Possibly not! Similarly, purchasing a generator with more power/output than you need makes much sense.

09. Does it come with accessories?

Some generators come with accessories or a piece of complete welding equipment, and some may come as an independent generator. If you’re a newbie and don’t have your numerous welding tools, the accessories may be handy.

Keep an eye on amperage information. Smaller generators have lower amps than (more significant) industrial generators. If you’re welding sporadically or on lightweight materials, you won’t require the industrial welder generator.

If you often weld for a living or welding plan, the industrial grade is the appropriate choice. It can operate for 6-12 hours (depending on the fuel tank size).


Above all, our recommendation is always to follow any safety instructions issued by your welder and generator manufacturer. They may even recommend specific generators or welders compatible with each other.

We hope that this post has proved very informative and that you are now sure that you can run a stick welder on a generator, providing the two are safe compatible.

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