Motor starter for AS-Interface lines — what fits in the panel
The 3RK4320-3LQ51-0BA2: CLASS 10 trip means it will clear a stalled rotor before the winding insulation cooks, which matters for conveyors and pumps that can jam. It communicates over AS-Interface (not PROFINET or PROFIBUS DP), so this goes on an AS-i network segment. Two digital inputs are built in, and there's a motor brake output (24 V DC) available — handy for holding brakes on vertical-axis drives without a separate contactor. IP54 enclosure means it handles dust and splashing water — fine for a machine-side cabinet but not washdown zones.
Mounting and panel fit — the numbers that matter
Dimensions: 245 mm wide by 215 mm high by 205 mm deep. That's a substantial footprint — it won't squeeze into a shallow junction box. That helps when the back panel is already crowded. The short-circuit protection is designed for circuit-breakers upstream — not fuses — so coordinate the branch circuit protection accordingly. Rated operating frequency is 80 operations per hour minimum, which is fine for intermittent starting duty but not for rapid cycling. If the panel runs hot near the top, derate or relocate. The unit is a direct starter with electromechanical contacts — no solid-state switching here, so coil buzz and contact wear are part of the maintenance cycle.