What this reversing starter does and where it fits
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. The IP65 rating means the housing and all connections tolerate washdown environments, so this part is common on food-and-bev or packaging lines where hose-down cleaning is routine. 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. The short-circuit breaking capacity at 400 V is 50 A, meaning the integrated circuit-breaker-type short-circuit protection clears a fault up to that level without the upstream device needing to trip. Ambient temperature range is 0–55 °C during operation.
Panel integration and wiring
The housing dimensions are 140 mm wide, 270 mm high, and 134 mm deep — a compact footprint for a reversing starter with bus communication and brake output. 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.