The Siemens 3RK1300-1BS01-1AA4 is an electromechanical reversing starter from the SIRIUS EM 300 RS family, designed for the ET 200X distributed I/O system. It combines two contactors and a bimetal overload relay in one IP65 housing, so it reverses a three-phase motor without a separate enclosure. The setting range is 1.4–2.0 A, matched to a 0.75 kW motor at AC-3 duty on a 400 V line — that is the full-load current window the bimetal element protects against overload. It communicates over PROFIBUS DP, which lets the PLC start, stop, and reverse the motor and read back the overload trip status over the fieldbus. The integrated brake output (rated DC 500 V / 1 A) powers an internally supplied motor brake directly — no separate brake rectifier or relay needed. That saves a DIN-rail slot and a wiring step on machines with holding brakes, like vertical conveyors or gantries. Operating voltage is 400–500 V AC, three-phase. Ambient temperature range is 0–55 °C during operation.
The main current circuit connects via tab terminals (9-pole motor feeder and 9-pole power connection), so the wiring harness is a single plug-in cable assembly rather than individual lug terminations. This speeds panel assembly and reduces wiring errors on repetitive machine builds. Because the unit is IP65 and self-contained, it mounts directly on the machine frame or a sub-panel, not inside a control cabinet. That saves cabinet space and keeps the motor power leads short. The PROFIBUS DP connection passes through a standard M12 bus connector — no special gateway required.