SIRIUS S0 Power Contactor, 24 VDC Coil
The Siemens 3RT1026-1BB44-3MA0 is a SIRIUS S0-frame power contactor with a 24 VDC magnet coil, rated for motor switching at 11 kW in AC-2 duty at 400 V and 15.5 A in AC-4 at 400 V. The coil draws 5.4 W both closing and holding, so the control transformer sizing is straightforward — no inrush spike to over-spec for. Screw-type terminals on both main and auxiliary circuits, with a 45 mm wide footprint that snaps onto 35 mm DIN rail per EN 50022.
Mounting and Integration
Fastens by screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022. Side-by-side mounting is permitted, which keeps multi-contactor motor starter assemblies tight on the rail. Front face carries IP20 protection; the terminal area is IP00 — standard for panel-mount contactors where the enclosure provides the overall ingress rating. Operating temperature range -25 to +60 °C covers most indoor industrial environments without derating.
Short-Circuit Coordination and Wiring
For Type 2 coordination (minimal damage to the contactor after a fault), Siemens specifies a gL/gG fuse rated 35 A. For Type 1 coordination (contactor may need replacement but the circuit is cleared), the fuse can go up to 100 A gL/gG. Main circuit terminals accept solid or stranded copper: 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), max 2x 10 mm². Auxiliary terminals take 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), max 2x 4 mm². AWG equivalents are listed for both.