What sits in the 22.5 mm slot
The ABB 1SVR730712R2200 is a thermistor motor protection monitoring relay — a single-sensor PTC guard with 2 c/o (SPDT) output contacts, screwed onto a 22.5 mm DIN-rail housing that takes the same footprint as a standard timer or interface relay inside a motor control cabinet (cites:,). Function-wise it covers the three jobs a thermistor relay has to do: one sensor circuit for a PTC probe embedded in the motor winding, short-circuit detection across the probe loop, and dynamic interrupted-wire detection — with auto/manual or remote reset selectable so the panel builder decides whether the relay latches or auto-restarts on a thermal trip (cites:).
Ratings that decide the fit
Two SPDT contacts is the useful number: one pole drives the upstream contactor coil to drop the motor, the second pole feeds the PLC discrete input or a fault beacon — so the integrator gets an independent trip path and an alarm path from a single device, rather than splitting the logic across two auxiliary relays (cites:). Sealing is split: IP50 on the housing face (finger-safe against casual contact once DIN-mounted) and IP20 at the screw terminals, which is the standard expectation for an enclosed cabinet — this is a control-panel device, not a field-side one (cites:).
Where it lives on the line
In a typical motor control circuit the CM-MSS line sits between the contactor coil and the PLC: PTC probes in the motor windings feed the single sensor circuit, the relay trips the contactor on overtemperature, and the second SPDT pole raises a fault flag back to the SCADA — a compact DIN-rail block that consolidates probe monitoring, trip logic, and the reset mode into one module (cites:,).