Siemens 3RN2010-1CW30 Thermistor Motor Protection Relay

Siemens 3RN2010-1CW30 Thermistor Motor Protection Relay is a compact thermistor-based protection device designed to guard motor windings by measuring winding temperature and interrupting the control circuit if overheating is detected. Housed in a 17.5 mm-wide compact evaluation unit with screw terminals, it provides one normally open and one normally closed contact and operates from 24 to 240 V AC or DC with Auto RESET. The unit offers galvanic isolation and two LEDs (Ready and Tripped) for clear status indication, and its enclosure carries an IP20 protection rating. It is designed for use with a bimetallic switch in motor protection schemes and draws about 0.9 W of power at the rated current. The device supports surge resistance up to 4 kV and an insulation voltage of up to 300 V, with robust reliability including typical mechanical switching life of around 10 million cycles and electrical endurance up to 100,000 AC-15 cycles at 230 V. By directly monitoring winding temperature, this Siemens SIRIUS 3RN2 relay helps prevent winding damage from overheating and provides a reliable, low-profile solution for protecting small to medium motors in automation panels.