What this reversing contactor assembly is — and what it replaces in a panel
The 3RA2318-8XB30-2AP0: This is a Siemens SIRIUS reversing contactor assembly — two mechanically interlocked contactors in one housing, so a single motor can be driven forward and reverse without a separate reversing starter or external interlocks. The supplied contactors inside are two 3RT2018-2AP02 units, size S00 frame. At 480 V it delivers 14 A; at 600 V, 11 A. The horsepower ratings span 3 hp at 200/208 V up to 10 hp at 460/480 V and 575/600 V. Mechanical life is rated at 10 million operating cycles — the interlock is a mechanical bar, not a relay, so there's no timing drift between the forward and reverse contactors.
Termination, wire sizes, and clearance — what fits in the enclosure
Both the main current circuit and the magnet coil use spring-loaded terminals (cage clamp style). No screwdriver torque to set — just strip and push. The envelope is 84 mm high, 90 mm wide, 83 mm deep — size S00 frame. Clearance requirements: 6 mm upwards, 6 mm downwards, 6 mm to the side, 6 mm forwards, 0 mm backwards (flush to the rail). That 0 mm rear clearance means it can sit tight against a back panel or a busbar shield. Vibration resistance is 11.4 g at 5 ms and 7.3 g at 10 ms for both AC and DC excitation.
Lifecycle and sourcing — active, quoted to order
RoHS compliance date is 10/01/2009 — the assembly meets the EU RoHS directive from that date forward.