Final answer:
The percentage of time a welder is actually welding is called the duty cycle. It's usually measured over a 10-minute period and ensures the welder does not overheat by regulating the time spent in active welding.
Step-by-step explanation:
The percentage of time that the welder is actually welding is known as duty cycle. It is a term commonly used in the context of welding to describe the amount of time a welder operates in a given period, usually represented as a percentage of a 10-minute interval. For example, a 60% duty cycle means the welder can weld continuously for 6 minutes and then must cool down for the remaining 4 minutes of the cycle to prevent overheating. It is important to select a welding machine with a duty cycle that matches the intended use to ensure both efficiency and machine longevity.