SIRIUS S0 power contactor for motor loads up to 11 kW
The Siemens 3RT1026-1BG40-1AA0 is a SIRIUS-branded power contactor in the size S0 frame, designed for switching three-phase motor loads in control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, occupying a 45 mm width — a standard slot in most industrial enclosures. Rated for AC-3 duty at 11 kW on both 500 V and 690 V supplies, this contactor handles the inrush of squirrel-cage motors during starting. For reversing or plugging duty (AC-4), it carries 15.5 A at 400 V — the rating that governs contact life under high electrical stress, not the AC-3 figure. The main circuit uses screw-type terminals accepting 2x (1 to 2.5 mm²) stranded, 2x (2.5 to 6 mm²), or a single 10 mm² conductor. Auxiliary contacts accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid, with a max of 2x (0.75 to 4 mm²). This wire range covers standard motor leads and control wiring without adapters.
Coordination and protection
For Type 2 coordination (no damage to the contactor after a short circuit), Siemens specifies a gL/gG fuse rated 35 A. Type 1 coordination (contactor may need replacement after a fault) allows a 100 A gL/gG fuse. The 35 A limit is the one to design around if the panel must survive a fault without component replacement. The contactor carries an IP20 rating on the front (finger-safe) and IP00 at the terminals, meaning it is intended for installation inside a locked or tool-accessible enclosure. Pollution degree 3 (conductive or dry non-conductive pollution) suits it for industrial environments where humidity and dust are present.
Coil and auxiliary contact ratings
The DC magnet coil draws 5.4 W during both closing and holding — no power reduction after pick-up, so the control transformer must supply continuous 5.4 W per contactor. Auxiliary contacts are rated across multiple voltages: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V DC. The 24 V DC rating (10 A) is the one to use for PLC output interfacing. Mechanical life is rated at 10 million operations typical — the electrical life will be lower and depends on the switching category and load current. Side-by-side mounting is permitted without derating, which simplifies panel layout.
Environmental limits
Operating temperature range is -25 to +60 °C during operation. Maximum installation altitude is 2 000 m above sea level.