Jason Heard

“Definition of Duty Cycle –One way of classifying the size of a welder is by the duty cycle rating. This is a universal rating given to welders that determines how hard you can “push” the machine during a 10-minute period. This measure is the number of minutes out of a 10-minute period the welder can operate continuously, with the remainder designated as the “cool down” period. An example of this is a Miller Dynasty 350, which can operate at 300 amps with a 60% duty cycle. That means the machine can operate at 300 amps for 6 minutes with 4 minutes of “cool down” time after continuous welding before starting another weld. If you exceed the welders’ limits, then you will overheat the machine and cause irreparable damage to its internals, thus breaking the machine. While the machine is in the “cool down” stage, be sure to NOT unplug it.”
― Jason Heard, Welding for Beginners in Fabrication