Siemens SIRIUS 3RT2018-2KF42-0LA0 — DC Coil Contactor, Size S00
The Siemens 3RT2018-2KF42-0LA0 is a SIRIUS contactor in size S00, built for DC coil control at 110 V. It uses spring-type terminals for the magnet coil — no screw torque to verify, just strip and push.
DC Switching Ratings and Coil Performance
This contactor is optimized for DC circuits. The coil picks up at 70% of rated voltage (77 V for a 110 V coil) and drops out at 1.25x the rated value — meaning it holds in firmly until the control voltage drops significantly. Arcing time runs 10–15 ms for the main contacts, with a DC arcing time of 7–20 ms depending on the load.
Wiring and Terminal Capacity
The spring-type terminals accept solid wire: 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), or 2x 4 mm². For solid or stranded wire, the range is 2x (0.5–4 mm²). That covers most control and power wiring in a panel — no special ferrules needed unless your standard calls for them.