Reversing contactor assembly — built from two 3RT2028-2AG20 contactors
The 3RA2328-8XB30-2AG2 is a Siemens SIRIUS reversing contactor assembly in the S0 frame size, supplied as a factory-matched pair of 3RT2028-2AG20 contactors with mechanical and electrical interlock already integrated.
Duty ratings that govern the motor match
At 400 V the assembly is rated 18.5 kW in AC-3 (starting squirrel-cage motors, switching off running motors) and 11 kW in AC-4 (plugging, inching, reversing under load) — the AC-4 figure is the one to size against if the application cycles direction under full load. The 110 V coil (50/60 Hz) means it pulls in on a standard control transformer secondary. Mechanical life is 10 million operations typical — the contactor pair is rated for the full reversing duty cycle without derating the mechanical endurance.
Dimensions are 114 mm high, 90 mm wide, 97 mm deep. Clearance requirements: 6 mm upwards, 6 mm forwards, 6 mm downwards, 6 mm at the sides, and 0 mm backwards — the back sits flush against the mounting surface.
The spring-clamp terminals and S0 footprint mean it drops into existing Siemens reversing-starter layouts without rewiring the main power circuit.