Panel fit and mounting constraints
The 3RH2244-2BB40: Its 45 mm width and 121 mm depth mean it occupies one standard modular unit on the rail, leaving room for adjacent devices in a crowded panel.
Rated current and contact configuration
This contactor carries 4 normally-open instantaneous contacts. That derating curve means the contactor's thermal capacity is the limiting factor at higher voltages — not the contact material itself. For a 400 V control circuit, budget 3 A per contact as the continuous rating. The coil is 24 VDC with a closing power and holding power of 4 W each. That low holding power means the coil won't overheat in a sealed enclosure, but the inrush at pickup is the same 4 W — no extra surge to stress a 24 VDC power supply.
The substance prohibition date of October 1, 2009 aligns with RoHS compliance for that vintage. Arcing time is 10-15 ms at AC and 7-13 ms at DC. That arc duration is short enough to avoid contact welding in most inductive load applications, but the DC arcing time is tighter — factor that into the contactor's DC switching capability.