What it is and what it does
The Siemens 3RT1015-2BB44-3MA0 is a SIRIUS power contactor in the S00 frame size, designed for switching motor loads and resistive loads in industrial control panels. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022, and main circuit connections use spring-loaded terminals — no screwdriver needed for the power wires, which speeds up panel wiring and reduces loose-termination callbacks.
Key ratings and what they mean for fit
The coil is 24 VDC, pulling 3.3 W to close and 3.3 W to hold — a constant-grab DC coil, so the holding power is the same as the inrush. That matters for DC-supply sizing: it draws the full 3.3 W continuously, not a pulse then drop. The contactor is rated 3 kW at 400 V in AC-2 duty (slip-ring motor starting), and 6.5 A at 400 V in AC-4 duty (plugging/reversing). AC-4 is the harder switching duty — the 6.5 A figure is the one to respect if the motor sees frequent reversing or inching. For AC-12 resistive loads, it handles 10 A. The operating temperature range is -25 to +60 °C, and the front face carries IP20 protection — fine for a closed panel, not for washdown.
Mounting and integration
This contactor fits the S00 footprint: 45 mm wide, 60 mm tall, 114 mm deep. Side-by-side mounting is allowed without derating, with a 6 mm gap to the side for airflow. The spring-loaded main terminals accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). The auxiliary contact block (2 instantaneous contacts) is integrated. For short-circuit coordination, Type 2 requires a 20 A gL/gG fuse; Type 1 allows a 35 A fuse. Pollution degree 3 means it's rated for industrial environments with conductive dust or occasional condensation.