The Siemens 3RT1015-1AN61 is a SIRIUS power contactor in frame size S00, designed for switching three-phase motor loads up to 4 kW at 690 V in AC-3 duty, or 3.5 kW at 500 V. It's a standard building block for motor starters in industrial control panels. Rated operational current in AC-3 at 400 V is not explicitly listed, but the 4 kW at 690 V and 3.5 kW at 500 V ratings indicate it handles motor starting currents typical of a 4 kW (approx. 5.5 HP) motor at 690 V, or a 3.5 kW (approx. 4.7 HP) motor at 500 V. For AC-4 duty (plugging, inching), the rated current at 400 V is 6.5 A — a lower continuous rating reflecting the higher thermal stress of frequent reversing or jogging.
IP20 on the front and at the terminals means finger-safe for the panel builder, but not washdown-rated — keep it inside a cabinet.
Screw terminals accept 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or max. 2x (0.75...4 mm²) solid/stranded, or AWG equivalents 2x (20...16), 2x (18...14), 1x 12.