The Siemens 3RT2023-1AC20-Z X95 is a size S0 power contactor from the SIRIUS 3RT2 series, rated for AC-3e/AC-3 duty at 9 A and 4 kW at 400 V. The 24 V AC coil operates on 50/60 Hz, and the screw-terminal block carries 1 NO + 1 NC auxiliary contacts for feedback or interlocking. The AC-3 rating means it's sized for starting and stopping squirrel-cage motors under load — the 9 A at 400 V translates to about a 4 kW motor, typical for small pumps, fans, or conveyors in a control panel.
Size S0 mounts on standard DIN rail or panel with two screws. The 24 V AC coil draws from a control transformer — verify the VA burden if sharing a transformer with PLC outputs or other contactors. Screw terminals accept up to 4 mm² stranded wire; torque to 1.2 Nm. The 1 NO + 1 NC auxiliary block is fixed, not field-swappable, so plan the feedback wiring around those contacts.