The ABB 1SVR740712R1400 is a CM-MSS.31 thermistor motor protection relay — it monitors PTC thermistor sensors embedded in motor windings and trips the contactor if the winding temperature exceeds the sensor threshold. That makes it the component that keeps a motor from cooking itself under overload, stalled-rotor, or blocked-vent conditions where a standard bimetallic overload relay might not react fast enough.
The CM-MSS.31 sits in a DIN-rail enclosure alongside the motor starter combination — typically between the contactor and the PLC digital output that resets the trip. The PTC input loop is a low-voltage, low-current circuit; noise pickup on unshielded sensor wiring can cause nuisance trips, so keep the sensor pair twisted and routed away from VFD output cables. The relay output is a single-pole changeover rated for the control voltage in the panel.