The Siemens SIRIUS 3RK1325-6LS41-3AA5 is a reversing motor starter — a self-contained unit that combines a contactor, overload relay, and reversing interlock in one IP65 enclosure, rated for 5.5 kW at 400 V and 7.5 hp at 460/480 V. It runs on a 24 VDC control supply (20.4 to 28.8 V) and supports trip classes 5, 10, 15, and 20, so you can match the overload curve to the motor's starting profile — Class 5 for short acceleration times on low-inertia loads, Class 20 for high-inertia starts like fans or centrifuges.
Deployment context
The screw-fixing mount (fastening method) secures it to a backplate or sub-panel; it accepts horizontal, vertical, or flat mounting positions, though horizontal is recommended for optimal heat dissipation. Power connections use a HAN Q4/2 plug per ISO 23570, and device addressing goes through an M12 plug.
The reversing starter handles forward/reverse motor control without external contactors — the interlock is built in, so a single unit manages direction change for applications like conveyor reversals or valve actuators. The 24 VDC control supply is standard for PLC-driven panels; the 85 ms ON-delay and 65 ms OFF-delay are internal timing for the reversing sequence, preventing a phase-to-phase short during direction change. Shock resistance of 12g at 11 ms and vibration resistance of 7 mm / 2g mean it survives the mechanical stress of a motor starter cabinet near a press or crusher.