SIRIUS 3RT1023-1DB44 — Power Contactor, Size S0, 24 V DC
The Siemens 3RT1023-1DB44 is a SIRIUS power contactor in Size S0, designed for switching motor loads in industrial control panels. The 24 V DC coil draws 5.4 W during closing and holding, so the control transformer or power supply must be sized for that inrush — a common oversight on retrofit swaps where the old contactor had a different coil draw. The contactor mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, and side-by-side mounting is permitted with 6 mm clearance at the side. Front face is IP20; the terminal area is IP00, meaning the panel builder must guard live parts behind the gland plate. Rated for motor duty: 4.5 kW at 500 V and 5.5 kW at 690 V. In AC-2 duty at 400 V it delivers 4 kW; AC-4 at 400 V is rated 8.5 A. The AC-12 maximum operating current is 10 A. For type 2 coordination, a 25 A gL/gG fuse is required; type 1 coordination calls for a 63 A gL/gG fuse. The contactor carries two instantaneous contacts and a varistor surge suppressor built into the coil circuit. Operating temperature range is -25 to +60 °C, with a maximum altitude of 2000 m. Pollution degree 3 suits the contactor for industrial environments with conductive dust or condensation. Mechanical life is rated at 10 million operations typical.
Termination and Wiring
Main current circuit uses screw-type terminals. Solid wire accepted: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded wire: 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), max 2x 10 mm². AWG equivalents: 2x (16 to 12), 2x (14 to 10), 1x 8. The terminal layout is standard for Size S0 — no special tooling required, but verify the wire range matches your cable before terminating.