The Siemens 3RT2016-2BM42 is a SIRIUS S00 power contactor — the smallest frame in the SIRIUS line, sized for motor loads and resistive heating in control panels up to around 7.5 kW at 400 V AC-3 duty. The S00 frame keeps the footprint tight at 45 mm wide by 70 mm tall by 73 mm deep, which matters when you're packing contactors into a crowded DIN-rail enclosure. The coil is 24 VDC with spring-type terminals — no screwdriver needed for the coil connection, which shaves a few seconds per termination on the line. Main contacts are rated for 20 to 12 A, and the contactor carries an auxiliary switch built in.
Clearances are specified: 10 mm upward and forward, 10 mm downward, 6 mm at the sides. That's the air gap needed for arc extinction and heat dissipation — don't crowd it tighter. The spring-type terminals on the coil side accept the same range.
Switching capacity and duty cycles
The main contacts are rated for 20 to 12 A — that's the continuous current range, not a single fixed value. For motor starting (AC-3 duty), the contactor can handle up to 750 operations per hour; for AC-4 (plugging/reversing) it's 250 per hour. AC-1 resistive loads allow 1,000 operations per hour. The mechanical life is typical 30 million operations, so it'll outlast most of the gear it's switching. Auxiliary contact ratings at DC voltages: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V. That covers most control-circuit voltages you'll see in industrial panels.