What it is and what it does
The Siemens 3RK1300-1CS01-0AA4 is an EM 300 DS electromechanical direct starter designed for the ET 200X distributed I/O system. It integrates motor starting, bimetal overload protection, and PROFIBUS DP communication into a single IP65-rated enclosure for remote or decentralized panel mounting. The setting range covers 1.8 to 2.5 A, with an AC-3 motor rating of 0.9 kW at 400 V — meaning it directly switches and protects a motor load up to that current in a standard three-phase induction motor application. The 50 A short-circuit breaking capacity (Icu) at 400 V ensures the unit can safely interrupt a fault up to that level without upstream damage. Operating voltage is rated 400 to 500 V DC for the control circuit, and the unit includes a motor brake output rated DC 500 V / 1 A for internally supplied brakes, connected via a 9-pole motor feeder and 9-pole power connection using tab terminals.
Where it fits in the panel
At 140 mm wide, 270 mm high, and 134 mm deep, this starter occupies a defined footprint within the ET 200X system. The IP65 rating means the enclosure and all connections withstand washdown environments — suitable for food-and-bev, material handling, or any line where hose-down cleaning is routine. Tab terminals on the main current circuit accept standard quick-connect receptacles; the 9-pole motor and power connectors are pre-wired to the internal brake contact and bimetal relay. Ambient temperature range of 0 to 55 °C covers most unconditioned cabinet environments.