Welding & Fabrication worked example

Welder Duty Cycle at 69% rated power source duty cycle at welding amps: a worked example

Push rated power source duty cycle at welding amps up to 69% and the picture changes. This example computes every intermediate figure at that operating point. Use it to check whether a welder is running inside the power source rated duty cycle before thermal protection trips, and to size machines for repetitive heavy welding.

The inputs for this scenario

  • Arc-on minutes in the cycle: 6 min (unchanged)
  • Total cycle period: 10 min (unchanged)
  • Rated power source duty cycle at welding amps: 69 % (raised for this scenario; the documented default is 60)

Working through the calculation

  • Applying the documented formula (Actual welder duty cycle = arc-on minutes in the cycle ÷ total cycle period × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 60 % duty for actual welder duty cycle, the number this scenario is built around.
  • At this operating point the engine returns 9 points for duty cycle margin to nameplate.
  • At this operating point the engine returns 6 count for arc-on minutes in the cycle.
  • At this operating point the engine returns 10 count for total cycle period.

How this compares with the baseline

  • Against the tool's baseline example, where rated power source duty cycle at welding amps sits at 60% and the headline result is 60 % duty, this scenario lands almost exactly on the baseline at 60 % duty.
  • It computes the actual percentage of a cycle the arc is on and the margin between that and the power source's rated duty cycle. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Actual welder duty cycle: 60 % duty (headline result)
  • Duty cycle margin to nameplate: 9 points
  • Arc-on minutes in the cycle: 6 count
  • Total cycle period: 10 count

Run it with your numbers

  • Every input above is editable in the live Welder Duty Cycle calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.