SIRIUS S3 power contactor — 77 A at 480 V, DIN-rail mount
The Siemens 3RT2045-1AT60 is a SIRIUS-brand power contactor in the S3 frame size, rated for 77 A at 480 V in AC-3 duty — that's the motor-switching current, not the resistive load number, so size it for your full-load amps on pumps, conveyors, or compressors. Mounts via screw and snap-on onto 35 mm standard DIN rail per DIN EN 60715, with a ±180° rotation possible on a vertical surface and ±22.5° tilt forward/backward — useful when you're fitting into a tight gland plate layout. Dimensions are 152 mm deep by 70 mm wide by 140 mm high, and the clearance distances are 10 mm upwards, 20 mm forwards, 10 mm downwards, and 10 mm at the side — factor those into your panel fill before you commit the backplate.
Wire terminations and coil connection
Main contact wire range accepts solid conductors from 2.5 to 16 mm² and stranded from 6 to 70 mm² — that covers most motor feeds up to the 77 A rating. Auxiliary contact wiring accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded — standard for control-circuit runs back to the PLC output card.
Switching frequency and operating conditions
Rated for up to 1 000 operating cycles per hour in AC-3 and AC-3e duty, 900 cycles/h in AC-1, 400 in AC-2, and 300 in AC-4 — the AC-3 number is the one you care about for standard motor starting. The arcing time sits between 10 and 20 ms at 60 Hz — that matters for coordination with upstream protection.