The 3RT2316-1AK60: The 4 kW AC-3 rating at 400 V is the number that decides motor fit — it tells you the contactor can switch a 4 kW induction motor under full-load starting and running without welding contacts. The 9 A rated operational current at 400 V is the thermal current for that same duty. The coil draws 0.24 A at both 50 and 60 Hz, so the control transformer sizing is straightforward. The S00 frame keeps the panel footprint tight — 45 mm wide, 58 mm high, 73 mm deep. Side-by-side mounting is allowed, with a 6 mm gap to adjacent devices.
Main circuit terminals are screw-type; the magnet coil also uses screw terminals. Wire sizes: solid 2x (0.5–1.5 mm²) or 2x (0.75–2.5 mm²); stranded 0.5–4 mm². Auxiliary contact terminals accept 20–12 AWG.