The Siemens 3RA2115-1CA15-1AK6 is a non-fused direct motor starter from the SIRIUS 3RA2 family, size S00. It ships as a pre-assembled unit: the 3RT2015-1AK61 contactor and 3RA1921-1DA00 link module are included, so panel builders get a single order code for the motor branch instead of sourcing contactor, overload relay, and wiring separately. Rated 750 W at 400 V (AC-3) and 1.1 kW at 500 V, this starter handles small induction motors — pumps, fans, conveyors — in control panels up to 690 V AC-3 maximum. Snap-mounts onto a DIN rail or screws to a backplate with an additional push-in lug. The S00 frame (45 mm wide, 167.2 mm tall, 97.1 mm deep) keeps the panel footprint tight.
No official successor part is published because none is needed — the 3RA2 series remains the current SIRIUS motor-starter platform. If a buyer is cross-referencing from an older SIRIUS 3RV or third-party starter, the functional match depends on the S00 frame size and CLASS 10 characteristic, not on a direct order-code swap.
That suits standard squirrel-cage motors with moderate acceleration times — common for pumps and light conveyors. For high-inertia loads (centrifuges, crushers) that need longer start times, a CLASS 20 or CLASS 30 overload would be required. The supplied contactor 3RT2015-1AK61 has an AC-3 rating of 690 V maximum. Verify the line-to-line voltage stays within that ceiling; the motor nameplate must also match the 750 W (1 hp at 460/480 V) capability. The thermal overload adjusts to the motor FLA, not the contactor size — set it per the motor nameplate. Not rated for outdoor installation without additional enclosure protection.
Snap-on DIN rail mounting per EN 60715 is the standard method; screw-mounting via the push-in lug is an option when DIN rail is not available. The S00 frame requires 45 mm of DIN rail width. Clearance: 20 mm upward, 10 mm downward, 9 mm at the sides — no extra space needed forward or backward. Main contact wiring accepts 0.5 to 4 mm² solid or stranded, or 2× (0.75 to 2.5 mm²) for paralleled conductors. Control voltage for the contactor coil is 93.5–121 V at 50 Hz or 96–132 V at 60 Hz — confirm the control transformer taps match before energizing.