What it is and what it does
The Siemens 3RK1322-0ES02-0AA4 is an AS-i compact direct starter from the SIRIUS family — a fully enclosed, IP65-rated motor starting unit that combines a contactor, bimetal overload relay, and AS-i bus interface in one housing. It's a DOL (direct-on-line) starter for small three-phase motors up to 0.1 kW at 400 V AC-3 duty, with a setting range of 0.28 to 0.4 A. The IP65 rating means the entire assembly — including the electromechanical switching contacts and the bimetal motor protection — is sealed against dust and low-pressure water jets, so it mounts directly on the machine frame or conveyor section without a separate control panel. That's the whole point of a compact starter: put the motor control right at the load, not back in a cabinet. It communicates over AS-interface (AS-i), the two-wire bus that carries both power and data on a single flat cable. The part has two integrated inputs for sensors (e.g., limit switches or presence detectors) and a motor brake output rated for 500 V DC / 1 A, so it can handle a DC brake coil directly without an external relay.
What the ratings mean for fit
The 0.1 kW AC-3 rating at 400 V tells you this is sized for very small motors — think fractional-horsepower drives on small conveyors, agitators, or positioning slides. The 0.28 to 0.4 A setting range on the bimetal overload matches the full-load current of those motors. Don't try to stretch it beyond 0.4 A; the bimetal element won't trip correctly above that. The 50,000 A short-circuit breaking capacity (Icu) at 400 V is a standout for a starter this small. It means the unit can safely interrupt a fault current up to 50 kA without welding its contacts or rupturing the enclosure — important when the upstream supply transformer can deliver that kind of energy. That rating is the SCCR for the whole assembly, not just the contactor. The -25 to +55 °C operating temperature range covers most factory-floor conditions, including unheated warehouses in winter. The DC voltage type on the control side means it expects 24 V DC nominal from the AS-i bus — no AC coil to worry about.
Where it goes and how it connects
This is a field-mounted unit, not a panel-mount device. The IP65 enclosure and tab terminals for the main current circuit (9-pole motor outgoing feeder and 9-pole power connection) are designed for direct machine mounting with a short cable run to the motor. The two integrated inputs let you wire local sensors back through the AS-i bus without a separate I/O block. The dimensions — 270 mm high, 120 mm wide, 190 mm deep — are the envelope for the complete starter housing. It's not a DIN-rail component; it bolts to a mounting plate or machine frame via its own footprint. Plan for clearance around the cable entries and the AS-i flat cable routing.