The Siemens SIRIUS 3RT1016-1VB42 is a Size S00 power contactor built for switching motor loads in control panels. It snaps onto a 35 mm DIN rail per DIN EN 50022 and uses screw-type terminals on both the main and auxiliary circuits — straightforward for a panel builder to wire up. The DC coil is rated at 24 V and pulls a constant 1.4 W whether closing or holding, which simplifies the power supply sizing. An integrated diode handles surge suppression right on the coil, so you don't need to add an external flyback diode across the coil terminals.
Ratings that matter for the motor circuit
For AC-3 duty — the standard for squirrel-cage motor starting — this contactor is rated to switch 4.5 kW at 500 V and 5.5 kW at 690 V. That's the number that decides whether it handles your motor load without welding contacts. The AC-4 rating at 400 V is 8.5 A, which covers inching and plugging applications where the contactor breaks full-load current during reversal. The auxiliary contact ratings are given at several voltage levels: 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. That covers pilot duty for PLC inputs or relay coils downstream. With Type of Coordination 2, the recommended fuse is a gL/gG 20 A; for Type 1 coordination, a 35 A fuse is specified. That keeps the contactor from welding under a short-circuit fault when the upstream breaker clears it.
Mechanical fit and environment
The contactor body is 45 mm wide, 57.5 mm tall, and 72 mm deep — a compact footprint that fits tightly on a 35 mm DIN rail. Side-by-side mounting is allowed, so you can gang several contactors without extra spacing. The enclosure carries IP20 on the front and at the terminals — that's finger-safe but not sealed, so it belongs inside a panel, not out in a washdown zone. Operating temperature range is -25 to +60 °C, which covers most industrial enclosures without derating. Wire sizes accepted: solid or stranded from 0.5 to 4 mm² on the main contacts, with AWG equivalents of 2x (20–16), 2x (18–14), or 1x 12. That handles standard motor leads up to about 4–5.5 kW.