When contactor coils fail, how does the failure process typically occur?

The failure of contactor coils typically occurs gradually, which aligns with the selected answer. This gradual breakdown can be attributed to several factors, including wear and tear over time, overheating, or insulation breakdown. As the coils experience repeated cycling and stress, their efficiency diminishes, often resulting in resistance changes, overheating, or intermittent operation.

This gradual failure is more common than immediate or catastrophic failures, which are often more dramatic and less frequent. Options that suggest sudden failure without warning or that it only happens after a specific event, such as a power surge, do not reflect the typical nature of contactor coil failures. Understanding this gradual process allows technicians to identify early signs of wear and intervene before a complete failure occurs, thus ensuring better maintenance and operational reliability.