The Siemens 3RK1301-0CB13-1AA4 is a SIMATIC-brand reversing motor starter — a single device that handles forward and reverse motor direction without external contactors or a separate reversing assembly. It's designed for the Siemens automation ecosystem, with native PROFINET and PROFIBUS DP protocols for direct fieldbus integration into a PLC or safety CPU. The overload protection is adjustable between trip Class 10 and Class 20, so you can tune the thermal curve to match the motor start profile — Class 10 for fast-starting pumps and fans, Class 20 for high-inertia loads like conveyors or crushers that need a longer acceleration ramp.
Reliability and safety metrics for spares and SIL planning
MTBF of 11 a gives the MRO planner a mean-time-between-failure figure for spares provisioning — roughly one failure per decade per unit under normal operation. The MTTFd of 31 a is the safety-related failure rate used in SIL (Safety Integrity Level) calculations per IEC 61508, which matters when this starter is part of a safety function circuit. The safe state is defined as load circuit open — meaning on loss of supply or fault, the output contacts open and the motor coasts to stop. This is the expected fail-safe behavior for a motor starter in a guarding or emergency-stop chain.
Installation and environmental fit
Mounts by plugging onto a terminal module — no hardwiring of the base unit, which cuts panel assembly time and simplifies swap-out. Acceptable in vertical or horizontal orientation, so it fits tight enclosures where space is constrained. Dimensions are 130 mm wide, 150 mm deep, 290 mm tall — a compact footprint for a reversing starter with integrated fieldbus. Pollution degree 3 at 400 V and degree 2 at 500 V per IEC 60664 / IEC 61131 — the higher degree 3 rating means it's designed for industrial environments with conductive dust or occasional condensation, without needing additional conformal coating on the PCB.
Supply voltage and control logic
Control supply is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V DC — standard for industrial 24 V panels. The rated value is 24 V, and the operating range is 21.6 to 26.4 V DC. Two digital inputs are available for control signals (forward/reverse commands), addressed via the fieldbus as 2 bytes of input and 2 bytes of output data. Supports reverse starting (reversing function) but not direct-on-line starting — the reversing logic is built in. Maximum operating frequency is 80 operations per hour, so it's suited for cyclic applications but not high-speed reversing.
Lifecycle stage is current.