Siemens SIRIUS 3RN2 Thermistor Motor Protection Relay 3RN2011-1BA30, 24 V AC/DC, 1 NO + 1 NC, Screw Terminals, DIN Rail

The Siemens 3RN2011-1BA30 thermistor motor protection relay stands out with its direct PTC thermistor sensing, offering precise thermal monitoring without additional transducers. It operates on 24 V AC/DC and provides one NO and one NC auxiliary contact for flexible signaling.

Highlights

• Monitors up to 6 PTC thermistors in series
• Auto, manual, or remote reset modes
• Screw terminals for secure wiring
• 35 mm DIN rail mounting
• IP20 protection for control cabinet use

In daily use

This relay protects motors from overheating by continuously measuring winding temperature via embedded thermistors. When the temperature exceeds the response threshold, the relay trips and opens the control circuit. The reset function can be configured for automatic restart or manual acknowledgment, depending on safety requirements.

Full specifications

• Supply voltage: 24 V AC/DC
• Auxiliary contacts: 1 NO + 1 NC
• Rated insulation voltage: 300 V
• Rated impulse withstand voltage: 4 kV
• Operating temperature: -25 to +60 °C
• Storage temperature: -40 to +80 °C
• Power consumption: 1.5 W (DC), 1.5 VA (AC)
• Electrical service life: 10,000,000 switching cycles
• Mechanical service life: 30,000,000 switching cycles

Final note

Ideal for industrial motor protection where direct temperature sensing is required, the SIRIUS 3RN2 relay ensures reliable operation and long service life.