What it is and what it does
The Siemens 3RK1301-1BB00-0AA2 is a SIMATIC-branded direct motor starter, designed for controlling and protecting three-phase motors in industrial automation panels. It integrates a CLASS 10 overload trip curve, meaning it will trip within 10 seconds at 600% of the set current — standard for protecting standard induction motors during start-up. The unit supports both PROFINET and PROFIBUS DP fieldbus protocols, allowing direct integration into a Siemens automation environment without a separate gateway.
Key ratings and what they mean for fit
The short-circuit breaking capacity is rated at 50 kA at 400 V, meaning this starter can safely interrupt a fault current up to that level without upstream fuses or breakers needing to clear the fault first — a key coordination figure for panel SCCR compliance. The control supply is 24 V DC, with a permissible range of 20.4 to 28.8 V, so it will hold in during a sagging 24 V bus but drops out before the logic supply browns out. Operating temperature range is 0 to 60 °C, with storage and transport tolerance from -40 to +70 °C.
Integration and mounting
This starter mounts by plugging onto a terminal module, not directly onto a DIN rail — the terminal module carries the main power wiring, and the electronics unit plugs onto it. This allows the electronics to be swapped without disturbing the power wiring. Dimensions are 265 mm high, 45 mm wide, and 120 mm deep. Mounting can be vertical or horizontal. The main energy infeed uses screw-type terminals. Pollution degree is rated 3 at 400 V and 2 at 500 V per IEC 60664, so it's suitable for industrial environments with conductive dust or condensation.