The Advantages of Inverter Welders

July 18, 2022 · Leave a comment · Red-D-Arc
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If you’re searching for a welding machine, you may stumble across descriptions such as “transformer” or “inverter.” If you are unsure which is best for your application, at least know this: transformer and inverter welders are perfectly capable of producing high-quality welds. However, keep in mind that most new models produced by industry-leading manufacturers are inverter-based.

Transformers are not necessarily bad, they are just “old school” compared to the “new school” inverter welders. An inverter and transformer power supply converts AC input power to DC output power suitable for welding. But just as the modern sedan can offer improved fuel economy through aerodynamics, lightweight materials, and engine design advancements, the inverter welder can also offer benefits to the welder through electrical technological advancements.

welder using inverter welder

Inverter History

The inverter-based welding power source traces its commercial origins to the 1980s, thanks to advancements in solid-state electrical components. At that time, the new inverter technology lacked the same reliability as the proven transformer technology. This reputation stuck even as high-amperage solid-state technology continued to advance. 

Today, inverter welders are much more reliable than when they were first introduced, have an increased practical lifespan, and can tackle applications not previously recommended, such as carbon arc gouging in-field welding conditions.

Advantages of Inverter Welders

Red-D-Arc FX650XL Inverter Welder Rental Machine

With reliability/lifespan concerns addressed, the advantages of inverters typically surpass those of the bulkier, less electrically efficient, and less “advanced” welding transformer in many applications.


Improved Efficiency

High-end transformer power sources can attain average efficiencies of 70-80% while inverters can offer average efficiencies of 80-85%. Power cost is typically 3-5% of total weld cost. While a 5% savings on 5% of weld cost may seem insignificant, power costs can become significant expenditures for large fleets, and power savings can certainly add up over the lifespan of the equipment.

Smaller Footprint, Lighter Weight

For a given rated output, transformer technology is bulkier—both heavier and physically larger—than the electronics that power inverter technology. For example, Lincoln Electric’s Idealarc DC-600 power source (a transformer-based unit) weighs 522 pounds, while Red-D-Arc’s inverter-based FX650XL has a similar output capacity and weighs only 165 pounds.

Weight reduction may not be the most significant advantage of an inverter in certain industrial manufacturing facilities where the power source never moves. However, weight is a critical consideration in applications with large weldments, such as shipbuilding, where the power source must frequently be moved in and out of a vessel.

Advanced Weld Process Control

”The ability to digitally control the nature of the welding arc improves response time to changes in input power and welding conditions for a more stable welding arc.”

Inverters work by first converting alternating current into direct current. Then, solid-state switches—which can be digitally controlled—invert the power back into the alternating current but at frequencies exceeding 20,000 hertz. Finally, a combination of a step-down transformer and filtering circuitry work together to convert this high-frequency current into a stable direct-current (DC) or usable alternating-current (AC) welding arc.

The ability to digitally control the nature of the welding arc improves response time to changes in input power and welding conditions for a more stable welding arc. Modern inverter MIG welding equipment couples this digital control with software to provide individual wire- and gas-specific pulsed waveforms that help tailor the welding arc’s performance to the application. Inverters also allowed further improvement of square wave alternating current for aluminum GTAW/TIG welding and high-deposition submerged-arc welding.

Picking the Best Inverter Welder

Simply put, the marketplace for inverter welder rentals can be pretty overwhelming. To help make sense of it all, contact our team today for customized guidance on welder rentals. But in the meantime, here are some questions that you could ask to help determine which inverter you might want to rent:

What process or processes are you looking to perform?

An inverter power source exists to perform virtually every standard arc welding process: SMAW (stick), GTAW (TIG), GMAW (MIG), FCAW, and SAW. In addition, several inverter arc welders have dedicated “modes” for carbon arc gouging and cutting (CAG/CAC). If your application requires or benefits from switching from process to process, multi-process power sources are not uncommon. Also, be aware that specialized inverter power supplies exist on the market for tackling tasks such as automated orbital GTAW welding of small-diameter sanitary tubing.

What is the maximum output current you will require?

Machines with a higher maximum output current will allow you to tackle thicker material in fewer passes (due to increased welding deposition rates) or with less joint preparation (due to greater weld penetration). 

Inverter-based power sources are available with maximum outputs ranging from 150 to 1000 amps! Be mindful of what is practical for your productivity goals since increased output power supplies are typically larger and more expensive.

Where will you be welding?

If you plan on welding in the field, there is still an inverter power source that can meet your needs. As mentioned earlier, inverter-based power sources are much more rugged than at their inception, and many are suitable for outdoor service. When access to the grid is problematic, engine-driven inverter welders exist. Some are even capable of advanced welding processes such as pulsed MIG with the right accessories!


Inverters have come a long way since their inception. If you are looking for cutting-edge features and welding performance, an inverter welding power source may be for you. Even if you don’t know all the answers to the questions above, the chances are good that Red-D-Arc’s team of experts can help you identify a welder rental that meets the needs of your application while adhering to your budget.

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