Which control circuit function will activate an alarm only after a vacuum pump has operated for 60 seconds?

The control circuit function that activates an alarm after a vacuum pump has operated for 60 seconds is correctly identified as the on-delay timer. An on-delay timer is designed to delay the activation of a circuit for a specified period—in this case, 60 seconds. This allows the system to ensure that the vacuum pump has been running long enough before signaling an alarm, which can be crucial for preventing false alarms that could occur if the pump only runs briefly.

By utilizing an on-delay timer, the control logic ensures that the alarm is not triggered immediately, but rather only after the pump has run for the designated duration. This is particularly important in industrial settings where machines like vacuum pumps need a moment to establish stable operations before monitoring outcomes such as vacuum levels or system failures.

The other choices do not fit the described scenario since a vacuum switch failing would not result in an alarm based solely on elapsed time. The automatic operation of the pump does not imply that an alarm is triggered after a duration. Immediate sounding of the alarm disregards the necessary timing of the pump's operation, which is fundamental to the proper functioning of the alarm system.