The Siemens 3RH1921-2DE11-Z X95 is a first lateral auxiliary switch with one normally-open and one normally-closed contact, encapsulated and marked solid-state compatible. It uses spring-type terminals and mounts directly onto 3RT1 contactors. The "first lateral" position means it clips onto the left side of the contactor (viewed from the front), occupying the first auxiliary slot. The solid-state compatible encapsulation means the contact gap and creepage are designed to handle the low-energy switching of PLC or solid-state relay inputs without contact welding or signal bounce issues.
RoHS compliance is confirmed since March 1, 2017. REACH candidate list information is available per the manufacturer's standard declaration.
The 1 NO + 1 NC contact arrangement covers the basic feedback pair most motor starter circuits need: the NO signals the contactor is closed (run status), the NC signals it's open (stopped or tripped). Encapsulation means it's sealed against dust ingress in the panel — no contact cleaning needed over the equipment life. Spring-type terminals (cage clamp) are faster to wire than screw terminals and hold better under vibration — relevant if this goes into a panel on a conveyor line or compressor skid. No special tool beyond a small flat-blade screwdriver to open the cage. The "first lateral" designation matters for multi-auxiliary stacks: if you need more than one auxiliary block, the second one goes on the right side (or stacks outward). Plan your contactor layout accordingly.