What this 24 VDC auxiliary contactor does that a standard power contactor cannot
The 3RH2140-2BB40-ZW96 is a SIRIUS auxiliary contactor, size S00, designed to switch control signals rather than motor loads — its 4 NO instantaneous contacts handle the logic-level interlocking and feedback loops that a power contactor's auxiliary block might not have the space or circuit count for. The 24 VDC coil draws 4 W both on closing and holding — no inrush spike to brown out a 24 V supply rail shared with sensors.