The Siemens 3RT2024-1BB40-1AA0 is a SIRIUS 3RT series power contactor, 3-pole, rated AC-3e/AC-3 at 12 A and 5.5 kW at 400 V. The coil is 24 V DC. It carries 1 normally-open and 1 normally-closed auxiliary contact, and terminates via screw terminals in the S0 frame size, intended for upright mounting.
The AC-3e/AC-3 rating at 12 A and 5.5 kW at 400 V means this contactor is sized for switching three-phase induction motors under starting and running conditions — the standard duty for a contactor in a motor control center. The 24 V DC coil is common in PLC-driven panels where a 24 VDC control supply is already present; the DC coil holds in without the hum of an AC coil, and its dropout voltage is typically well below 24 V, giving noise immunity on the control line. The S0 frame size dictates the DIN-rail footprint and the terminal spacing; at 115 x 93 x 57 mm packaged, it fits standard panel layouts.
Integration notes
The screw terminals accept the usual panel-building wire range for a 12 A contactor. The auxiliary contact block is integrated — 1 NO + 1 NC — so no separate add-on block is needed for basic feedback to the PLC. The upright mounting position is specified for proper arc quenching; horizontal mounting would derate the switching capacity.