SIRIUS S00 coupling contactor — 24 VDC coil, spring-cage terminals
The Siemens 3RT2016-2SB42 is a SIRIUS S00 coupling contactor with a 24 VDC coil, spring-type terminals, and screw/snap-on mounting to 35 mm DIN rail per DIN EN 60715. The coil picks up at 0.85 × rated voltage (20.4 V) and drops out at 0.15 × rated voltage (3.6 V), so it holds reliably on a 24 VDC nominal supply but releases cleanly on undervoltage. Main contacts are rated 20 A down to 12 A depending on duty, and the auxiliary contact block carries 10 A at 24 VDC, 2 A at 48/60 VDC, tapering to 0.3 A at 220 VDC — enough for signal feedback on DC control circuits in panels or safety loops.
Panel fit and mounting flexibility
Clearance requirements: 10 mm above and below, 10 mm forward, 6 mm to the side — tight enough for dense panels. Spring-cage terminals accept 0.5 to 4 mm² solid or stranded wire, or 2 × (0.5 to 4 mm²) for looping through. Strip length is 10 mm — no ferrule needed for stranded if the wire is tinned.
Maximum switching frequency depends on duty: 1,000 cycles/hour at AC-1 (resistive), 750 at AC-2 and AC-3 (motor starting/running), 250 at AC-4 (plugging/inching). The AC-3e rating also caps at 750 cycles/hour. These limits govern thermal rise in the coil and contacts — exceeding them shortens life or causes welding. Mechanical life is typical 30 million operations, so for a line running 750 cycles/hour, the contactor lasts roughly 40,000 hours before the mechanism wears. DC switching times are 5 to 20 ms closing, with arcing time 10 to 15 ms — fast enough for most interposing relay or PLC-driven loads.
Temperature range and lifecycle status
Lifecycle stage is current production, so this is a standard BOM line item with no imminent end-of-life notice. No auxiliary switch is fitted as standard, but the spring-cage terminal block supports field-installed auxiliary contact blocks if needed.