What this reversing starter is and what it does
The Siemens SIMATIC 3RK1308-0BB00-0CP0 is a reversing motor starter — a single module that handles forward/reverse control of a three-phase motor without external contactor interlocking. It's rated 1 A at 40 °C and carries a 55 kA short-circuit breaking capacity at both 400 V and 500 V, so it can be placed on a high-fault panel bus without needing upstream current-limiting fuses for the starter itself. The trip class is adjustable: CLASS OFF, 5, or 10, which means you can match the thermal overload curve to the motor's starting profile — useful when the same module is used across different load types like pumps and conveyors.
Fieldbus and integration
This module supports PROFINET and PROFIBUS DP natively. Input data is 4 bytes, output data 2 bytes. It plugs into a base unit; width is 30 mm, depth 150 mm.
Environmental and mechanical limits
Operating temperature range is -25 to +60 °C with derating above 40 °C; storage and transport range is -40 to +70 °C. Vibration resistance is 15 mm at 6 Hz, then 2 g up to 500 Hz; shock resistance is 6 g for 11 ms. Pollution degree 2, overvoltage category III — standard for industrial control panels. The safe state is load circuit open, meaning on fault or communication loss the outputs drop out and the motor coasts or brakes per the external circuit.
Supply voltage and load considerations
Supply voltage range is 20.4 V to 28.8 V. Minimum load is 50% of the smallest adjustable rated current. ON-delay is 20 ms; OFF-delay is 35 to 50 ms.