4 NO auxiliary switching in a 45 mm S00 frame
The 3RH2344-1DW40 is a SIRIUS auxiliary contactor — four normally-open instantaneous contacts in a size S00 housing that fits a 45 mm wide DIN-rail footprint. A built-in varistor clamps the coil suppression, so you do not need an external RC snubber or freewheeling diode on the DC coil side. The magnet coil draws 4 W at DC, which keeps the heat rise low inside a crowded panel.
The DC switching capacity is given as a time range of 7–13 ms, which covers the arc extinction window for most control loads. Mechanical endurance is 10 million operations typical; the AC switching frequency is 10,000 cycles per hour. That makes it a fast mover for high-cycle signalling applications like conveyor interlocks or valve position feedback.
No direct successor or cross-reference is listed; the 3RH2344-1DW40 is the standard variant with varistor suppression and 4 NO contacts in size S00. For a panel originally built around a different auxiliary contactor, compare the 45 mm width and the 4 NO configuration — if the footprint and contact count match, it drops in without rewiring.