Siemens SIRIUS 3RT2018-2LB42-2LA0 — S00 Contactor, 24 VDC Coil, Spring-Terminal
It carries a 24 VDC magnet coil terminated via spring-type terminals — no screw torque to verify, which saves time on the panel build and eliminates a common field failure point (loose screw connections under vibration). Main contacts are rated for 20 A down to 12 A (the range covers the standard AC-3 motor duty and AC-1 resistive load curves for this frame). The auxiliary switch is integrated, with switching capacity documented per the DC voltage rail: 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, 3 A at 400 V, 14 A at 480 V, 2 A at 500 V, 11 A at 600 V, and 1 A at 690 V — these are the values to use when sizing the control circuit, not the main power path.
The S00 footprint is 45 mm wide by 70 mm high by 121 mm deep — a standard slot that fits alongside other SIRIUS S00 components on the same rail without stealing extra width. Conductor terminations on the spring-type terminals accept solid or stranded wire: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), 2x 4 mm², or 2x (0.5 to 4 mm²). Strip length per the terminal manufacturer's recommendation — the spring cage holds firmly when the conductor is fully inserted.
Environmental and Timing
The coil pick-up and drop-out times at DC are 7 to 20 ms, and the arcing time on the main contacts is 10 to 15 ms. The maximum switching rate under AC-4 duty (plugging / inching) is 250 operations per hour. For continuous motor starting (AC-3), the rate is higher — consult the thermal derating for your specific load current.