Siemens SIRIUS 3RT1054-1QF35 — what this power contactor is and what it handles
It carries a 96-127 VAC coil and uses screw-type terminals on both the main circuit and the magnet coil, which is the standard fit for panel builders who prefer screw terminations over spring-cage for high-current connections. The main circuit accepts stranded conductors from 16 to 70 mm², so it lands comfortably on a motor branch circuit up to that wire gauge. The auxiliary switch is included as standard, saving an add-on order for basic feedback.
Switching duty and operating rates — matching the contactor to the load profile
The 3RT1054-1QF35 is rated for different switching frequencies depending on the duty category. At AC-3 (standard motor starting) it handles up to 1,000 operations per hour; at AC-1 (resistive loads) it is rated for 800 ops/h; at AC-2 (slip-ring motors) it drops to 400 ops/h; and at AC-4 (plugging/inching) it is limited to 130 ops/h. Switching times are 80-90 ms for both AC and DC operation, with arcing time of 10-15 ms.
Mounting, clearances, and environmental limits
Mounting is by screw fixing on a vertical surface, with the contactor rotatable ±90° and tiltable ±22.5° to the front and back. This gives flexibility for tight enclosures where the DIN rail is not perfectly aligned. Dimensions are 172 mm height, 140 mm width, and 170 mm depth.