The Siemens 3RT2017-1VB42 is a SIRIUS coupling contactor — size S00, meaning it's the compact footprint in the family, built for switching signals and smaller loads in control circuits rather than main motor power. It's rated for 24 V DC coil voltage and switches 10 A at 24 V, so think of it as the relay that bridges a PLC output to a larger contactor or drives a small solenoid bank directly. The S00 body is 45 mm wide, 58 mm tall, and 73 mm deep — fits in a tight panel or a crowded junction box. Clearance requirements are modest: 10 mm above and below, 10 mm forward, 6 mm sideways.
The 24 V DC coil has a pickup threshold of 0.85 x rated (about 20.4 V) and a dropout of 0.1 x rated (2.4 V) — that wide dropout margin means it stays pulled in through a sag but drops cleanly when the control signal goes away. Switching frequency depends on duty: up to 1000 cycles/hour at AC-1 (resistive), 750 at AC-2 or AC-3 (motor start/run), and 250 at AC-4 (plugging/inching). Wire termination is screw-type, accepting 0.5 to 4 mm² solid or stranded, and up to 2x 4 mm² or 2x (0.75 to 2.5 mm²) with ferrules. No auxiliary switch built in — this is a bare coupling contactor; if you need aux contacts, you add a side-mount block separately.