What this direct starter is and what it does
The Siemens 3RK1300-0HS01-0AA3 is an EM 300 DS electromechanical direct starter from the SIRIUS family, designed for the ET 200X distributed I/O system. It integrates a contactor, bimetal motor protection, and short-circuit protection into a single IP65-rated enclosure, so it mounts directly on the machine or in the field — no separate control cabinet needed for this motor branch. The setting range of 0.55...0.8A and AC-3 rating of 0.21 kW at 400 V mean it is sized for small three-phase induction motors — pumps, fans, conveyors — where the full-load current falls within that window. The bimetal overload relay provides thermal memory for starting under load; the integrated circuit-breaker-style short-circuit protection clears faults up to 50 A at 400 V (Icu). This unit includes a motor brake output, so it can control an internally supplied DC brake on the motor — common for holding loads on vertical axes or conveyors. The main current circuit connects via tab terminals; the 9-pole motor feeder and 9-pole power connection are part of the ET 200X plug-in architecture. PROFIBUS DP is onboard for communication back to the PLC, eliminating a separate fieldbus coupler for this motor starter.
IP65 and field-mount deployment
Rated IP65, the enclosure is dust-tight and protected against low-pressure water jets from any direction — suitable for washdown areas, food processing zones, or outdoor installation under a canopy. The 270 mm height, 140 mm width, and 134 mm depth fit the ET 200X form factor; it bolts to a mounting plate or machine frame, not a DIN rail. The tab terminals on the main circuit accept fast-on connectors; the 9-pole power and motor feeder cables plug in via the system connector. Ambient operating temperature range is 0 to 55 °C.
SCCR and coordination note
The maximum short-circuit breaking capacity (Icu) at 400 V is 50 A. This is the fault current the integrated short-circuit protection can interrupt without external fusing. For a panel designer, this means the branch SCCR is capped at 50 A at 400 V — verify that the available fault current at the point of installation does not exceed this value. The short-circuit protection design uses circuit-breakers (integrated), not separate fuses.