Final answer:
The continuous running time for which a welding machine was designed is described by the term 'duty cycle'. It represents the percentage of time the machine can operate continuously in a given period before needing to cool down.
Step-by-step explanation:
The term used to describe the continuous running time for which a welding machine was designed is duty cycle. The duty cycle of a welding machine indicates the percentage of time that it can operate continuously before needing to cool down. For instance, if a welding machine has a duty cycle of 40%, it means that it can run for 40% of a given time period, such as 4 minutes out of a 10-minute cycle, after which it will require a cooling period to prevent overheating. This specification is critical for users to understand to avoid overloading the machine and to ensure optimal performance.