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Arc welding

Looking for an energy-efficient arc welding machine?

An arc welding machine is a device used for fusing metals. The machine emits an electrical arc from an electrode which melts metal or supplies filler into a joint between two pieces of metal. To produce the temperatures up to 3,600ºC needed to fuse metals, arc welding machines consume significant quantities of energy.

Arc welding technology and energy efficiency

Many arc welding machines sold today use far less energy than older models, even when they are idling. Newer units fitted with inverter power sources are lighter, more versatile and more energy efficient than those powered by older, transformer-rectifier power sources.

Here is how the models compare: The old, transformer-rectifier equipment had energy conversion efficiencies that ranged from 40 to 60 percent and consumed 2 to 5kW when idling. Those with inverter power sources have energy conversion efficiencies near 90 percent and consume around 0.1 kW when idling.


  • Inverter power sources can be up to 50 percent more efficient than transformer-rectifier power sources and draw one-twentieth of the power when idling.
  • Inverter power sources have power factors (the ratio of power available for use to the power consumed by the unit) that are close to 100 percent; transformer-rectifier power sources’ percentages are far lower.
  • Inverter power sources are far lighter than transformer-rectifier power sources, meaning they are more portable and require fewer people to operate.
  • Welding professionals, fabricators and manufacturers can find more information at The Canadian Welding Association.

Buying tips

What should you consider when buying an arc welding machine?

Low power first.
Start by finding the lowest-powered inverter power source that is well suited to your needs.

Choose multi-process equipment.
Some arc welding machines are suited for specific types of welding only. Pick the model that best meets all your needs.

Look for a power factor of 99 percent or higher.
Modern inverter power sources have power factors (the ratio of the power being used by the arc welding system to the power you pay for) approaching 100 percent; transformer-rectifier power sources operate around 75 percent.

Look for an energy conversion efficiency near 80 percent.
Energy conversion efficiency is the product of volt-ampere output over volt-ampere input. Check the manufacturer’s equipment data sheet for precise values.

Look for idling power consumption of less than 0.1 kW.
All arc welding machines consume power while idling. Units with inverter power sources, however, consume far less than those with transformer-rectifier power sources.

Choose your supplier wisely.
Buy from a reputable supplier that provides field maintenance and offers an all-parts warranty of at least two years.

Operating tips

Follow these best practices for even more energy savings.

Use trained welders.
Trained welders work quicker than those without training, and are usually more conscious of the need to save energy.

Be efficient.
Trained arc welders commonly practice five welding processes, some of which are more energy-efficient than others. For example, choose gas metal arc welding over shielded metal arc welding. The operating factor (the ratio of the time spent welding over the total time in use) of the former is greater, and thus idling time is reduced.

Use multi-process inverter power sources.
Arc welding machines with modern inverter power sources can be used for multiple welding processes and can quickly switch between such processes to minimize idling.

Consider incorporating computer-driven welding for routine operations.

Don’t idle.
Only turn on the welding machine when you are ready to weld. An idling arc welding machine consumes energy and costs money. Reduce idling time by completing set-up tasks before switching on the machine to weld. After the welding is done, turn off the machine before completing follow-on tasks.

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