Star-delta assembly for 15 kW motor starting
The Siemens 3RA2425-8XF32-1BB4 is a factory-assembled SIRIUS star-delta contactor assembly for wye-delta starting of three-phase motors. It ships with two 3RT2026-1BB40 contactors and one 3RT2024-1BB40 contactor, plus the RS assembly kit 3RA2923-2BB1 — everything needed for the transition from star to delta is integrated on the mounting plate. The S0 contactor frame size keeps the assembly compact — 135 mm wide, 101 mm high, 181 mm deep — fitting standard 35 mm DIN rail with screw and snap-on fastening.
Motor power ratings and duty cycle
The 15 kW rating at 400 V AC-3 is the headline figure for standard 400 V mains — this is the motor power the assembly can switch under starting duty. Maximum switching rate under AC-3 duty is 1,000 operations per hour, with a mechanical life of 10 million cycles typical for the contactors. The coil closing power at DC is 13.8 W, and the coil terminals are screw-type — no special control voltage wiring beyond standard 24 V DC.
Mounting and wiring constraints
Clearance requirements: 6 mm upwards, forwards, downwards, and to the side, with 0 mm backwards — the assembly can sit flush against the back panel. All terminals are screw-type — no spring-cage tooling required.