The Siemens 3RA2125-1KA24-0AK6 is a SIRIUS non-fused motor starter — a direct-on-line (DOL) combination that integrates a contactor and a thermal bimetallic overload relay in a single size S0 package. It is designed for starting and protecting three-phase induction motors under AC-3 duty.
Snap-mounted onto a DIN rail or screw-mounted with an additional push-in lug. Mounting position is vertical only. Dimensions: 45 mm wide × 193.1 mm high × 97.1 mm deep. The S0 feeder size and S00 circuit-breaker size mean it fits standard Siemens panel layouts alongside other SIRIUS components. Clearance requirements: 30 mm upwards, 10 mm forwards, 10 mm downwards, 9 mm at the side, and 0 mm backwards — plan your enclosure depth and ventilation accordingly.
The 3RA2125-1KA24-0AK6 is rated for a maximum operating voltage of 690 V AC-3. Motor power output varies by supply: 5.5 kW at 400 V, 7.5 kW at 500 V, and 10 hp at 575/600 V. The coil is AC-operated with a rated control voltage range of 88…121 V at 50 Hz and 96…132 V at 60 Hz — confirm your control transformer taps match these bands. The supplied contactor is a 3RT2024-1AK60; the link module is 3RA2921-1AA00. The main circuit wiring accepts stranded conductors from 1…10 mm² (two per terminal 2.5…6 mm²).