In IEC contactor life expectations, which two counts are commonly specified?

• A. Electrical operations and mechanical operations
• B. Electrical operations only
• C. Mechanical operations only
• D. Cycles per minute

Answer: (A)

In IEC contactor life expectations, two counts are commonly specified: electrical life and mechanical life. Electrical life is the number of operating cycles the contactor can perform while switching a rated electrical load, accounting for wear from arcing and contact erosion under current. Mechanical life is the number of cycles the device can perform with no current, reflecting wear in the moving mechanism, springs, and linkages independent of electrical arcing. Together, these two ratings give a complete view of how long the device remains reliable both under load and during normal mechanical operation.

The option that lists both electrical and mechanical operations fits because it captures the distinct wear mechanisms that affect life under load versus no-load. A choice that mentions only electrical operations would miss mechanical wear, while one that mentions only mechanical operations would miss arcing-related wear. Cycles per minute, while relevant to duty or speed, is not a measure of life expectancy.