Final answer:
The duty cycle of an arc welder indicates the percentage of time it can be actively used in a 10-minute period for safe and efficient operation.
Step-by-step explanation:
The duty cycle of an arc welder refers to the continuous operating time in a ten-minute period that represents the percentage of time the welder can be actively used before it needs to cool down. This concept is critical for safety and efficiency in welding operations. When a welder has a duty cycle of, for example, 40%, it indicates that the welder can operate safely for 4 minutes out of every 10-minute interval. Exceeding the duty cycle can lead to overheating and potential damages.