The Siemens 3RN1011-2CK00 is a thermistor motor protection evaluation unit designed to monitor motor winding temperature via PTC thermistors. It provides one normally open and one normally closed auxiliary contact (1 NO + 1 NC) and is rated for 230 V AC at both 50 Hz and 60 Hz. Spring-loaded terminals simplify wiring — no screwdriver needed for clamping, which speeds panel assembly and reduces torque variability. The 22.5 mm width matches standard single-module DIN-rail enclosures, so it occupies one slot in a crowded control cabinet.
For existing panels that carry the 3RN1011-2CK00, sourcing is through surplus or broker channels against an RFQ. No last-time-buy window is stated; the replacement is a direct functional fit.
The 91 mm depth leaves clearance for wiring ducts; the 103 mm height fits standard 120 mm enclosure depth. The unit includes a reclosing lockout function, meaning that after a motor overtemperature trip, the output contacts will not re-energise until the fault condition clears and the lockout is manually reset — a standard requirement for preventing automatic restart of a hot motor.