What it is and what it does
The Siemens 3RV1021-0GA15-ZW97 is a SIRIUS motor protection circuit breaker designed for motor protection. It provides overload and short-circuit protection for motors up to 0.18 kW at 400 V, with a continuous current rating of 0.63 A and a Class 10 trip characteristic. Class 10 means the breaker trips within 10 seconds at 7.2× the rated current, matching the thermal time constant of standard induction motors during a locked-rotor event. This prevents nuisance tripping on startup while still protecting the motor winding. The unit includes phase failure detection, which disconnects the motor if one phase is lost — a common cause of single-phasing damage in three-phase motor loads.
Breaking capacity and short-circuit performance
Rated breaking capacity is 100 kA at 240 V, 400 V, 500 V, and 690 V AC — a flat high-fault curve that covers most industrial distribution panels without needing upstream current-limiting fuses. The rated insulation voltage is 690 V, matching the maximum operating voltage of the main contacts.
Mounting and integration
Mounts via screw and snap-on onto a 35 mm standard mounting rail per DIN EN 50022. The 45 mm width fits a standard 45 mm module slot in a motor control center or panel. Dimensions: 45 mm wide, 97 mm high, 96 mm deep. The 96 mm depth means it will clear most standard 120 mm deep enclosures without a sub-panel extension. Mounting position is any orientation; no derating required for side-by-side or inverted mounting. Front face is IP20 rated — touch-safe for panel installation, but not suitable for washdown environments without an additional enclosure.
Terminal capacity and wiring
Main current circuit terminals are screw-type, accepting solid conductors: 2× (0.5…1.5 mm²) and 2× (0.75…2.5 mm²). Stranded conductors: 2× (1…2.5 mm²) and 2× (2.5…6 mm²). This covers most motor feeder cables up to 6 mm². Auxiliary switch is transverse design, rated at 1 A at 24 V, 0.5 A at 230 V, and 0.15 A at 60 V — sufficient for signaling to a PLC input or contactor coil.
Environmental and lifecycle
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Shock resistance is 25g / 11 ms, suitable for machine-mounted applications with moderate vibration. Mechanical endurance of the main contacts is 100,000 operations typical; maximum switching frequency at AC-3 duty is 15 operations per hour.