What it is and what it does
The Siemens 3RV2031-4WA10-ZW97 is a SIRIUS motor protection circuit breaker designed to protect motors against overload and short-circuit. It is rated Trip Class 10, meaning it will trip within 10 seconds at a locked-rotor current—fast enough to protect standard induction motors from thermal damage during start-up stalls. Its interrupting capacity is 30 kA at 400 V, which covers most industrial distribution panels fed by a transformer of that voltage class. At 690 V it still breaks 2 kA, so it handles fault clearing in mixed-voltage motor control centers. Built-in phase failure detection is a critical feature: if one supply phase drops, the breaker opens before single-phasing can cook the motor winding. No ground-fault detection on this variant, so pair it with a separate ground-fault relay if the installation requires it.
Mounting and integration
Snap-on mounting onto 35 mm DIN rail per DIN EN 60715, with screw fixing also supported. Width is 55 mm, depth 149 mm, height 140 mm. Clearance requirements: 50 mm upwards, 50 mm downwards, 10 mm at the side, zero forwards or backwards. That side clearance is tight—useful when packing multiple breakers in a row on a DIN rail. Main circuit terminals are M6 screw-type, accepting 2x 1–35 mm² or 1x 1–50 mm² solid or stranded copper. Strip and torque per Siemens guidelines; the M6 size is common across the SIRIUS 3RV2 frame.