SIRIUS S12 Power Contactor — Panel Fit and Ratings
The Siemens 3RT1076-2AR36 is a SIRIUS-brand Size S12 power contactor, screw-fixed to the mounting surface, with the coil rated for 440 to 480 V AC. It occupies 160 mm width, 214 mm height, and 225 mm depth — a substantial frame that needs a backplate with 11 mm mounting holes and a single-hole pattern. Coil pick-up threshold is 0.8 times the rated value. Magnet coil uses spring-type terminals. Mechanical life is typical 10,000,000 operations.
Switching Capacity and Duty Cycles
The 3RT1076-2AR36 carries auxiliary contacts rated at 10 A at 24 V, 2 A at 48 V, 2 A at 60 V, and 1 A at 110 V — these are the signal-level ratings for the built-in auxiliary switch block. Maximum operating cycles per hour vary by duty: AC-1 (resistive) allows 500 ops/h, AC-3 (motor starting) allows 420 ops/h, AC-4 (plugging/inching) drops to 130 ops/h — the AC-4 figure is the one to watch for reversing or jogging applications. AC-3e (enhanced motor starting) also rates 420 ops/h, matching the standard AC-3 figure. Power factor at both 50 Hz and 60 Hz is 0.9, and the full-scale overload factor is 1.1 — meaning the contactor can handle 10% above its rated current for short durations.
Wiring and Clearance
Main circuit wiring accepts stranded conductors from 70 to 240 mm² — typical for a Size S12 contactor handling high motor currents. Auxiliary circuit terminals accept 2x (0.25 to 2.5 mm²) solid or stranded wire, spring-cage style, matching standard control wiring practice.