SIRIUS S10 Vacuum Contactor — 3RT1264-6NB36
Vacuum contactors are the standard choice for applications requiring frequent switching under load — the arc extinguishes in a sealed vacuum bottle, so contact wear is minimal and the switching chamber stays clean across millions of operations. Rated for power conductors from 70 mm² up to 240 mm² stranded, this contactor handles the main circuit of large motors, transformers, or resistive loads. The coil is rated for a 21-27.3 VDC control voltage, with a 1.1x full-scale pickup factor and a dropout threshold around 0.8x nominal — typical for Siemens DC-operated contactors. Mechanical life is listed at 10 million operations typical, and the contactor supports switching frequencies up to 800 cycles per hour in AC-1 duty (resistive), 750 in AC-3 (squirrel-cage motor starting), and 250 in AC-4 (plugging/reversing). The vacuum bottle keeps arcing time to 10-15 ms, which helps with contactor coordination in motor control centers.
The 3RT1264-6NB36 measures 210 mm high, 145 mm wide, and 206 mm deep. It mounts via screw fixing through four 11 mm holes on a 1-hole pattern per pole. The coil has screw-type terminals accepting 2x (0.5-1.5 mm²) solid/stranded, 2x (0.75-2.5 mm²), or max 2x (0.75-4 mm²). The main power circuit uses the larger 70-240 mm² stranded connection. An auxiliary switch block is included, with rated currents of 10 A at 24 V, 2 A at 48 V and 60 V, and 1 A at 110 V — sufficient for signaling back to a PLC or control relay.