ABB – 1SVR730722R1400 – CM‑MSS.21S Thermistor Motor Protection Relay, 24–240 VAC

The ABB CM‑MSS.21S (1SVR730722R1400) is a DIN‑rail thermistor-based motor protection relay designed to safeguard motors and generators from overheating. It supports PTC thermal sensors and provides advanced features like short-circuit and wire-break detection, automatic reset, and ATEX certification—ideal for industrial environments.

Key Features:

• Model: CM‑MSS.21S / 1SVR730722R1400  

• Supply Voltage: 24–240 V AC/DC  

• Sensor Input: Single PTC thermistor circuit (DIN EN 44081/2)  

• Outputs: 1 N/O + 1 N/C (SPDT), 4 A @ 250 VAC / 4 A @ 24 VDC  

• Fault Detection: Overtemperature, short-circuit, open-wire; auto-reset on recovery  

• Indicators: Green power, yellow relay status, red fault LEDs  

• ATEX Certified: Suitable for hazardous area use  

• Mounting & Wiring: 22.5 mm DIN-rail; screw-terminals with cage technology; IP50 housing, IP20 terminals  

• Operating Temp: −25 °C to +60 °C; withstands 4‑kV impulse, IEC 60947‑8 certified  

• Dimensions: 22.5 × 85.6 × 103.7 mm, weight ~126 g