What is an auto-fail?

An auto-fail refers to a situation where a fault occurs that interrupts the Automatic Transfer Switch (ATS) sequence. This is crucial for ensuring the reliability and functionality of power systems. When a fault is detected, the auto-fail mechanism activates to protect the system from further damage or instability. In this context, it signals a failure in the primary power source that requires immediate switching to a backup power source, automatically safeguarding the continuity of power supply to critical loads. The auto-fail feature is designed to enhance the resilience of power systems by reducing downtime during unforeseen faults, thereby ensuring that operations can continue seamlessly.

The other options do not accurately define an auto-fail. The normal operating condition implies a state where all systems are functioning correctly, while the preventive maintenance procedure focuses on scheduled service tasks to prevent faults rather than responding to them. The predefined operational setting refers to specified parameters that govern how equipment should operate under normal circumstances, but it does not address the function of auto-fail, which is specifically designed to react to faults.