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You are watching: How big of a generator do i need to run a welder

What size generator execute I need to run a welder?

I obtain asked that a lot.

There are great reasons why it makes sense.

You need to repair a door that’s no close enough to family members powerA friend’s van is damaged down the end on the trailYou desire to build a greenhouse in your garden

But if it’s too small, you can damage or kill your high-quality welder.

Too big, and also it may cost too much to run, be tough to move, and also take up too much room.

How to number Out What size Generator For her Welder

This concern usually takes among these forms, because that example:

What size ggenerator carry out I require for a 180 amp welder?Will a 7,000-watt generator run a welder?How huge of a welder have the right to you run v a generator the X size?

These room actually every the same questions. You’re just asking it from different viewpoints.

This Is just how You perform It

Generators, like welders, come in too many of various sizes. There room a many of attributes and choices available. And you’ll have to decide if you desire 120-volt output, 240 volts, or both.

The trickiest point to watch the end for is that generators are rated in complete WATTS of power output, however welders are rated for calculation AMPERAGE.

That way you require to figure out how countless watts a welder needs to create its rated amps.

How countless Watts Does your Welder Use?

There’s a very simple math equation come move earlier and forth between volts, amps, and watts:

Volts x Amps = Watts

Volts: The technical definition is “a measure up of the distinction in electrical potential between two points.”

Think of volts in the same method you think that water pressure. The the accessible “push” the gets the electrical energy going.

Amps: Amperes room a means to measure up the flow of electric current.

Keeping v our water it is provided analogy, think that amps as the rate of circulation in the pipes, quick or slow.

Watts: A watt measures warmth energy. Together electrons circulation through the circuit, friction makes heat, measure up in watts.

So what you require is the voltage the welder uses, multiplied by the intake amps the the welder.

Find your Welder’s input Power

Step 1: uncover the strength & present levels

First, you need to understand what power and current levels her welder needs to run. A commonplace to find this details is in the manual.

Here’s an instance from the manual for the PrimeWeld pole 160.


Checking the specifications, as soon as again, there room numbers here for “Current Input”. This brand is less complicated to job-related with 보다 some since it offers both input voltage and also the input current needed through the welder.

It’s basic to figure out just how much strength you need in watt from a generator for her welder. For the 140-amp version, multiply:

120 volts intake x 23 amps = 2,760 watts

That’s just the an easy number, however. It’s characteristic that power devices to usage much an ext power to start than that takes to store them running.

Generator makers advise adding up come 30 percent to the running watt to account for beginning devices.

2,760 watt x .30 = 828 watts

Add this 30 percent safety and security margin come the basic running number of 2,760 watts:

2,760 + 828 = 3,588

This quantities to 3,600 watts. This welder will need a generator rated in ~ 2,800 operating watts, with a optimal rating that 3,600 watts.

Take far notes:

DON’T FORGET to add specified tolerance, choose our example was plus or minus 15 percent. ALWAYS include THE yongin IN.REMEMBER to ADD 30 percent come your complete wattage to cover the starting surge. The exception to this rule is if you’re utilizing a value known as “I1max“. Watch the following section for more information.Input Values have the right to Have other Names too

Sometimes over there are several different varieties of electrical ratings. You might not have a rating ~ above the label that’s specifically referred to as “input voltage” or “input current,” yet there are other names because that them.

No must be confused, however. Check for values v these names instead:

Input VoltageMax PowerMax VoltageV max or VmaxU max or UmaxU1maxInput CurrentMax AmperageMax CurrentA maxI maxI1max

Note that selection 5 in both instances has a notation that 1max. This name specifically suggests main input power.

I2 or I2max method output power.

The I1max rating is already adjusted for surging or starting watts. If you calculate with I1max, you currently have her maximum starting watts rating without a need to include 30 percent.

Another unit you occasionally see on a generator because that welders is the Kilovolt Amp or KVA.

For this unit 1,000 volts x 1 Amp = 1 KVA, the same as 1 Kilowatt (Kw).

Remember: Volts x Amps = Watts

Because 1 KVA = 1 Kw, a generator that provides 6 KVA of optimal power is likewise rated at 6 kW.

Power supply Differences between Inverters & Transformers

One important choice is whether her welding machine is powered by a transformer or is one inverter welder. This matters due to the fact that with generators for welders, over there is a quality called “dirty power.”

“Dirty Power” means small and also repeated fluctuations in the power level as the engine runs.

These fluctuations in power are referred to as “harmonic distortion” and also measured in units of complete Harmonic Distortion, or THD. The presented as a percentage, for instance, “5 percent THD.”

Transformer-powered welders are fairly forgiving the dirty power from a generator. Virtually any contemporary generator deserve to run a transformer-powered welder.

The trouble is with inverter-powered machines. Commonly called IGBT and MOSFET welders, lock have problems with dirty power because their manage circuits are conveniently damaged through harmonic distortions in the strength supply.

Without gaining too technical, this designs usage capacitors come filter the end distortion, smoothing the power supply. Another benefit that inverter strength is the welder itself deserve to be lighter.

A lot of modern-day generators are designed with inverter filters, do them safe for inverter-powered welders.

If you have a transformer-powered welder, THD isn’t a problem, but if you desire to run a computer, noþeles digital, or an IGBT or MOSFET welder, you should be listed below 6 percent THD.

Other factors Affecting your Choice

High Altitude Issues

At high altitudes, there’s less oxygen. Gasoline, diesel, and propane engines run much less efficiently, making much less power. Her welding generator will make less wattage in ~ high altitudes than it would certainly at sea level. Generator makers advise planning on a 3.5 percent power loss because that every 1,000 feet that elevation.

Depending top top the elevation, it can be barely noticeable, or it could be a lot less power. Generator machines offer high-altitude kit to help.

Extra Tools and also Equipment

If you have to run extra tools choose saws, grinders, drills and also the like, you require to include at least an additional 2,000 watts to the capacity due to the fact that many grinders and reciprocating saws take it as lot as 1,800 watt to operate.

Also, take into consideration fans, heaters, and also lighting. It might actually it is in cheaper come buy a smaller sized generator for these accessories than one large one to run both your welder and extra tools.

Here’s a partial list of common devices and also their strength demands:

ApplianceRunning WattsStarting Watts
Coffee Maker17500
625W Microwave625800
Single 60W indistinguishable CFL bulb150
Room waiting Conditioner: 10,000 BTU15002200
Small Appliance2001700
8in. Bench Grinder14002500
Pressure Washer: 1 HP12003600
7-1/4in. Circular Saw14002300
Electric Chain Saw: 14in. Bar, 2 HP11000
10in. Table Saw18004500
Drill: 3/8in., 4 Amps440600
Drill: 1/2in., 5.4 Amps600900
Portable Heater (Kerosene, Diesel Fuel): 90,000 BTU500725
Battery Charger: 60 Amp through 250 Amp Boost1500/57500
LCD computer system Monitor250
Inkjet Printer150
Cell phone Charger100

How long Is the run Time?

This is how long a generator can run at complete demand, with a complete tank the fuel. Some deserve to run as lengthy as 8-10 hours, when some huge generators could only critical a couple of hours between refills if they’re working hard.


Generators are loud, although typically not as loud as part tools and also vehicles are. There are likewise exhaust fumes come consider, through the risk of carbon monoxide. Girlfriend can’t put a generator inside safely, and also they all have labels informing you not to perform this.

You need to make certain it’s ventilated well, protected from collisions or reduce items, cords deserve to reach your work-related area safely, and noise won’t be a difficulty where it’s sitting.

Check the dB rating to see how loud that is. Anything end 90 dB is damaging to hearing. 120-decibel ratings and over are identical to precise deafening sounds prefer drag racers, artillery, jet aircraft, and also hunting rifles.


This chart offers some National electrical Manufacturers (NEMA) references on extension cord length. Anytime possible, plug devices directly into the generator.

Your coffee machine can brew until you take it a break, then you can pour a cup when you to walk over and also shut turn off the generator.

Total Wattage10 gauge cord12 gauge cord14 gauge cord16 gauge cord
2,400250 feet150 feet100 feet75 feet
4,800125 feet75 feet50 feet25 feet
7,20060 feet35 feet25 feet10 feet
9,60030 feet15 feet10 feet0
12,00015 feet000

Generators through 4Kw or more running wattage can easily weigh over 2 hundred pounds. Wheel kits, wheelbarrow-style handles, and lifting bales because that hooks room all items the make points a lot much easier when positioning such a heavy piece of equipment.

Related: What size Wire for Welder extension Cords?

Generator Sizing Chart for Welders

Here’s a rapid reference table I placed together to give you an idea that what size generator you should be aiming for, relying on your welder’s current level.

Welder existing LevelMinimum Generator SizingRecommended Generator Size
Up come 160A7kva 0r 7000 watts8000+ watts
180–200A8kva or 8000 watts10,000+ watts
210-250A13kva or 13,000 watts15,000+ wats

Best Generators for Welders

I’m walk with comprehensive portable generators here.

You don’t want your generator working too hard, running level out. It’s much easier on your brand-new power tree if it’s not breathing hard to get the project done.

See more: How To Reset Oil Light On 2007 Honda Civic 2006, How To Reset Oil Life: Honda Civic 2005

Cleaner and an ext consistent power, much less wear, and also longer life space the rewards the a small extra investment.