Ratings and fit for the BOM line
The Siemens 3RT2024-2DB44-3MA0 is a SIRIUS 3RT power contactor rated for AC-3e/AC-3 duty at 12 A, switching 5.5 kW at 400 V across three poles. The 24 V DC coil includes a plugged-in varistor for suppression. The auxiliary contact block carries 2 NO + 2 NC contacts, factory-integrated as a captive auxiliary switch. The AC-3 rating governs motor switching — starting and disconnecting induction motors under load. The 24 V DC coil is standard for PLC-driven panels; the varistor handles the back-EMF from the DC coil, so no external flyback diode is needed across the coil terminals. The captive auxiliary switch means the 2 NO + 2 NC block is physically locked to the contactor — it cannot be separated during maintenance, which keeps the auxiliary wiring intact when swapping the main contactor.