The Siemens 3RK1301-0AB10-0AB4 is a SIMATIC-branded motor starter configured as a direct starter — meaning it connects the motor straight across the line without reversing or soft-start circuitry. It is designed for a 24 V DC control supply (rated 20.4 to 28.8 V DC) and supports both PROFINET and PROFIBUS DP fieldbus protocols, so it drops into a SIMATIC S7 environment or any automation network that speaks those buses. The unit handles 2 bytes of input data and 2 bytes of output data — enough for motor status feedback and start/stop commands over the bus. Two digital inputs are available on the control module for local signals like a start button or interlock.
The trip class is selectable among 5, 10, 15, and 20, which means the overload relay can be set to the thermal memory curve that matches the motor's starting profile — a fan starting unloaded can use Class 10, while a high-inertia load like a centrifuge might need Class 20 to avoid nuisance tripping during acceleration. Mounting position is vertical or horizontal, so it fits tight enclosures where you might need to lay the starter on its side. The fastening method is pluggable onto a terminal module — no hardwiring to the base; the control and power connections are made through the terminal module, which stays in the panel when you swap the starter itself. Dimensions are 150 mm deep, 65 mm wide, and 290 mm tall — a slim footprint for a motor starter that includes the overload relay, contactor, and fieldbus interface in one package. The width is the critical number for DIN-rail density: at 65 mm, you can fit several side by side in a standard 600 mm wide enclosure.