What this AS-i compact starter is and what it does
The Siemens 3RK1322-1FS02-0AA1 is an AS-Interface compact starter in a direct-on-line (DOL) electromechanical configuration. It's a self-contained motor start-and-protect unit rated for 1.9 kW at AC-3 duty on a 400 V three-phase line, with a setting range of 3.5 to 5 A per the bimetal overload relay. The IP65 enclosure means this unit is designed for distributed mounting directly on the machine or conveyor frame — not inside a central control panel — so it can live in washdown zones or dusty environments without an additional cabinet.
Key ratings and what they mean for fit
The 1.9 kW rating at AC-3 (400 V) is the motor-switching capability — this covers standard three-phase induction motors up to that shaft power. The 3.5 to 5 A setting range on the bimetal relay lets you dial in the full-load current of the connected motor within that window. The 50 kA breaking capacity (Icu) at 400 V means this starter can safely interrupt a fault current up to 50,000 A without catastrophic failure, which is important for installations with high available fault current from the supply transformer. The IP65 rating is not just about dust and water jets — it means the enclosure seals against hose-directed water, so this unit is suitable for food processing lines, car wash bays, or any area where washdown is part of the sanitation cycle. The operating temperature range of -25 to +55 °C covers most indoor industrial environments and cold storage applications.
AS-Interface integration and connectivity
This starter communicates over AS-Interface (AS-i) protocol, not PROFIBUS DP. That means it connects to the AS-i yellow flat cable via a standard piercing technique — no shielded twisted pair, no termination resistors. The unit has two integrated digital inputs for local sensors (e.g., limit switches or presence detectors) and a motor brake output rated for 24 V DC / 3 A. The main circuit connection uses tab terminals, so you'll need mating fast-on connectors for the motor and power cables.