S10 vacuum contactor, 750 AC-3 cycles per hour
The 3RT1264-6AU36: Rated for 750 switching operations per hour in AC-3 duty (and AC-3e), this contactor handles the start-run-stop cycle of a squirrel-cage motor without exceeding thermal limits — the vacuum interrupter keeps arc erosion low even at that rate. The coil is rated 240-277 V with a pickup threshold of 0.8 × rated value, meaning it pulls in reliably even if the control voltage sags to about 192 V.
Fastened by screw fixing through a single 11 mm diameter hole — no DIN-rail clip on this frame; the panel builder drills and bolts it down. Clearance distances: 10 mm upwards, downwards, and to the side; 20 mm forwards — plan the enclosure layout around these minimums for arc flash and cooling.
Duty cycle and mechanical endurance
Mechanical life is 10,000,000 cycles typical — the vacuum bottle and the actuator mechanism are the long-life components; the auxiliary contacts will need inspection earlier in high-switching applications. Switching frequency varies by duty: 800 1/h in AC-1 (resistive), 750 in AC-3 (motor start), 300 in AC-2 (slip-ring motor), and 250 in AC-4 (plugging/inching) — match the application class to avoid overheating the coil or the arc chamber.