The Siemens 3RN1011-2BB00 is a thermistor motor protection evaluation unit from the SIRIUS family, designed to monitor motor winding temperature via PTC thermistors and trip on overheat. It operates on 24 V AC/DC supply and provides two changeover (CO) contacts for alarm and trip signaling.
Rated 24 V AC/DC means the unit accepts either AC or DC control voltage at 50 or 60 Hz without reconfiguration — simplifies panel wiring where a mixed-voltage control circuit exists. The 2 CO contacts give you two independent form-C relay outputs, enough to drive a separate alarm lamp and a PLC input or contactor coil. The reclosing lockout function prevents automatic restart after a motor overtemperature trip, which is critical for applications where a hot restart could damage windings or equipment. This is a safety feature, not a convenience timer.
Width is 22.5 mm, depth 91 mm, height 103 mm. Fastening is screw and snap-on mounting.
The substance prohibition date of 05/28/2009 indicates RoHS compliance per EU Directive 2002/95/EC. The reference code according to IEC 81346-2 is K, classifying it as a controlgear or protective device in system documentation. No UL, CSA, or CE mark is explicitly listed in the available data, but Siemens SIRIUS components typically carry CE marking for the European market; verify specific approvals for your jurisdiction before specifying.