Switching rates and auxiliary contact capacity
The 3RT2017-4AG61: Rated for 1,000 operations per hour in AC-1 duty (resistive loads), 750/h in AC-3 (motor starting), and 250/h in AC-4 (plugging/inching) — the AC-4 ceiling is the limiting factor for high-cycle reversing applications. Arcing time spans 10 to 15 ms at AC, with a switching-on time of 4 to 15 ms — this matters for coordination with upstream protection devices that must hold through the inrush without nuisance tripping.
