SIRIUS 3RA2 non-fused motor starter, Size S0
The Siemens 3RA2125-0GA23-0AK6 is a SIRIUS non-fused motor starter, Size S0, configured as a direct starter — meaning it combines a contactor and overload relay in one unit for simple on/off motor control with thermal and magnetic protection. The magnetic short-circuit trip handles fault clearing. It ships with a 3RT2023-1AK60 contactor, a 3RV2011-0GA15 circuit-breaker (Size S00), and a 3RA2921-1AA00 link module — all pre-assembled and wired internally. The auxiliary switch option is built in, so adding feedback to a PLC or safety relay is straightforward.
Motor ratings and duty — CLASS 10, 690 V AC-3
The AC-3 rated maximum is 690 V — this is the voltage ceiling for switching squirrel-cage motors under full load. At 400 V the unit handles 180 W; at 690 V it handles 250 W. The operating frequency is 50 to 60 Hz, with the coil rated 88–121 V at 50 Hz and 96–132 V at 60 Hz. The 6 kV rated surge voltage resistance (impulse withstand) means the starter can handle transient spikes on the line without flashover — important for industrial environments with switching surges from nearby drives. Pollution degree 3 rating means it's suitable for environments with conductive or dry non-conductive pollution — typical for control panels near production floors, not clean rooms.
Mounting and clearances — DIN rail or screw-mount
Snap-mounts onto 35 mm DIN rail (EN 60715) or screw-mounts with an additional push-in lug. The vertical mounting position is specified — horizontal mounting would affect the bimetallic trip curve and is not recommended. Dimensions: 45 mm wide, 97.1 mm deep, 193.1 mm high. Clearance requirements: 30 mm upward, 10 mm forward, 10 mm downward, 9 mm at the side, 0 mm backward (flush to the panel backplane). These matter for heat dissipation and for accessing the auxiliary switch wiring. Operating temperature range is -20 to +60 °C — standard for indoor panel installation. Storage range is -50 to +80 °C; transport range is -55 to +80 °C.