Understanding Duty Cycle Before You Buy An Inverter Welder
Before choosing a machine, it's worth checking what your workshop's consumer unit and incoming supply can actually handle, not just what socket is nearest the bench. Buying a three-phase-only machine for a single-phase workshop, or underestimating the load a higher-output single-phase welder places on existing wiring, are both avoidable problems with a bit of checking upfront.
Budget for a first machine is rarely just the welder itself. A gas cylinder and regulator for MIG or TIG, a decent auto-darkening helmet, gloves and basic workshop ventilation all add to the real cost of getting started, and skimping on the supporting equipment tends to cost more in frustration than it saves in cash. It's worth pricing the whole set-up before settling on a machine at the top of the budget.
Every workshop is different, so rather than relying on general advice, it's worth getting your own set-up properly assessed. A system that works well for one shop can be quite wrong for another with different ventilation, floor space or process mix, and an on-torch extraction option, such as those available for Fronius torches, suits a different layout to a fixed overhead hood.
The figure changes with output. Turn the amperage down and the duty cycle climbs, because the internal components are working less hard. This is why a welder can feel completely different in a busy production environment compared with occasional home workshop use: someone welding continuously through a shift needs a much higher duty cycle at their working amperage than someone doing short repair jobs a few times a week. It's the kind of spec worth comparing properly across brands such as Kemppi and EWM, not just reading off the headline amperage figure.
Duty cycle is one of the most misunderstood figures on a welder's spec sheet, yet it tells you more about real-world usability than the headline amperage does. It's expressed as a percentage over a ten-minute period at a given output, so a machine rated at 30% duty cycle at its maximum amperage can run for three minutes out of every ten at that setting before it needs to rest and cool.
Most people buying their first welder get stuck at the same fork in the road: Tec Products Ltd MIG, TIG or MMA. Each process strikes an arc differently and suits a different type of work, so the right choice depends more on what you'll be building than on which machine looks the most impressive on a shelf.
