Auxiliary Contact Block for 3RT2 and 3RH2
The Siemens 3RH2911-2HA31-Z X95 is an auxiliary switch block that mounts on the front of 3RT2 contactors and 3RH2 contactor relays, providing 3 normally-open and 1 normally-closed contact set for signaling or interlocking in a motor control center. The contacts are rated for switching control circuits and are terminated with spring-loaded (cage-clamp) terminals, which speeds wiring and resists loosening under vibration compared to screw terminals.
Lifecycle and Sourcing
RoHS compliance is confirmed from October 2009 onward, and the part carries no export control restrictions (AL: N / ECCN: N), simplifying cross-border procurement.
Contact Configuration and Wiring
The contact arrangement is 3 NO + 1 NC, with the NC contact on the first pole position (current path identified as 1 NC, 1 NO, 1 NO, 1 NO). This is a common pattern for signaling a contactor's energized state while providing one break contact for safety interlocks. Spring-loaded terminals accept solid or ferruled stranded conductors without needing a screwdriver torque check, which is useful in high-vibration environments like compressor or pump panels.