The ABB CM‑MSS (SVRR) is a DIN-rail motor protection relay that monitors winding temperature via PTC thermistor sensors. Designed for single-motor protection, it offers reliable overload protection by opening its SPDT contacts when the PTC sensor exceeds ~. kΩ, with shorted/broken sensor detection. Ideal for industrial motors, pumps, or HVAC systems.

Key Features & Specifications

Model / P/N: CM‑MSS / SVRR
Supply Voltage: – VAC ±%, / Hz
Control Supply Range: – VAC/DC series also exists; this one is specifically – VAC
Sensor Circuit: Monitors single PTC sensor; trips above ~. kΩ, resets below ~. kΩ
Sensor Fault Detection: Detects short-circuit (< Ω) or open circuit, indicated by flashing red LED
Output Contacts: × SPDT (form C); rated  A @  VAC
Reset Options: Manual front-button, auto-reset, or remote reset via terminal
LED Indicators: Green = supply OK; Red = fault
Mounting & Dimensions: . mm wide ( module), . × . × . mm; ~. kg
Approvals: UL , CSA, GL, GOST, CE; thermal & phase safety per IEC/EN ‑
Durability: Engineered for continuous motor operation; used and new units available on eBay around USD –

ABB – CM-MSS (1SVR430811R1300) – Thermistor Motor Protection Relay, 220-240 VAC

ABB – CM-MSS (1SVR430811R1300) – Thermistor Motor Protection Relay, 220-240 VAC