The Siemens 3RK1315-6NS71-0AA5 is a SIRIUS direct motor starter — a self-contained unit that combines a contactor and overload relay in one housing, sized for motor loads up to 4 kW at 400 V or 5 hp at 460/480 V. It's a CLASS 10 trip, meaning it will disconnect the motor within 10 seconds at 7.2× the full-load current — fast enough to protect a standard induction motor from locked-rotor heat buildup without nuisance tripping on startup. Runs on 24 V DC control power (20.4 to 28.8 V operating range, max 31.6 V) and talks AS-Interface for fieldbus integration. Four digital inputs are built in, addressable via an M12 plug — handy for picking up limit switches or pushbuttons right at the starter without a separate I/O block. The enclosure is IP65, so it's sealed against dust and water jets — fine for washdown areas, outdoor conveyor drives, or any spot where a panel isn't practical. Mount it vertical, horizontal, or flat; screw fixing to the machine frame or a subplate. Dimensions: 294 mm wide, 215 mm tall, 159 mm deep.
Integration & wiring
Main power connects via a HAN Q4/2 plug per ISO 23570 — a standard industrial connector that's quick to mate and strain-relieves the cable. The control and AS-Interface link use M12 connectors; keep the AS-i bus termination at the last device on the line. With a width of 294 mm, it takes up a fair bit of real estate on a subplate. Plan for side clearance if you need to access the M12 plugs or the HAN connector. The screw-fixing pattern is straightforward — four screws into the mounting surface. Rated for pollution degree 3, so it's suited for industrial environments with conductive dust or occasional condensation. Vibration resistance is 2g at 7 mm amplitude; shock resistance is 12g for 11 ms — typical for machine-mounted gear near a press or conveyor.
Timing & protection
The starter has a built-in ON-delay of 25 ms and OFF-delay of 35 ms — these are fixed, not adjustable. They prevent contact chatter during fast voltage dips or bus transitions, but don't rely on them for sequenced starting; that's what the AS-Interface network is for.