What this coupling relay does in a control panel
The 3RH2122-2MB40-0KT0 is a SIRIUS coupling relay — essentially an auxiliary contactor that bridges the PLC output to the main contactor coil or other loads in the control cabinet. It's sized in the S00 frame, the smallest footprint in the SIRIUS family, so it fits where panel space is tight. The coil pulls 24 VDC at 1.6 W both on pickup and hold — no inrush spike to sag the DC bus. That matters when you're running a string of these off a single 24 VDC power supply; the steady-state draw is predictable and low. The 2 NO contact configuration gives you two isolated signal paths per relay.
Mounting and panel fit — DIN rail and clearances
Mounts on 35 mm standard DIN rail with either screw or snap-on fastening. Dimensions are 70 mm high, 45 mm wide, 73 mm deep. The S00 frame keeps the width under 50 mm, so you can pack several side-by-side on a single DIN rail segment.
Lifecycle and sourcing — still in active production
Sourced to order against the BOM quantity through independent distribution.