Vacuum switching for high-cycle motor duty
The 3RT1275-6AB36 is a SIRIUS vacuum contactor in the Size S12 frame, designed for applications where high switching frequency and long mechanical life are critical — think conveyor systems, pump cycling, or compressor control that runs thousands of operations per hour. Rated for 750 AC-3 cycles per hour maximum and 700 AC-1 cycles per hour, with a typical mechanical life of 10,000,000 operations. The vacuum arc-quenching chamber keeps contact erosion low, so the switching rate doesn't eat into service life the way an air-break contactor would.
Panel fit and clearance zones
Mounts via screw fixing (two 11 mm holes) with dimensions 225 mm deep, 160 mm wide, 214 mm tall. These are the minimum air gaps to adjacent metalwork — ignore them and the arc flash can track to ground during a fault interruption.
Control circuit and auxiliary contacts
Coil terminals are screw-type, rated for 23-26 V control supply with a pickup factor of 1.1x rated and a dropout threshold of 0.8x rated. AC and DC dropout times both fall in the 60-100 ms range, with arcing time 10-15 ms — this matters when coordinating with upstream protection devices that need to ride through the contactor's opening arc. That covers most PLC input circuits and control relays in the panel. The auxiliary contacts are wired separately from the main power path, so the feedback signal stays clean even when the main contacts are switching motor inrush.