the time a machine could work based on attendance time (i.e. the working day or week, including overtime).

the time when a machine is temporarily out of productive use owing to changeovers, setting, cleaning and so on.

the time during which a machine is available for production or ancillary work, but owing to shortage of work, materials or workers, it includes the time that the plant is out of balance.

the maximum time a machine or group of machines could work within a given period.