The Siemens 3RT2047-3AL20 is a 3-pole power contactor from the SIRIUS 3RT family, rated for AC-3e/AC-3 duty at 110 A — that's the motor-switching current for a 55 kW load at 400 V. The 230 V AC coil pulls in on 50 or 60 Hz, so it works straight off a standard control transformer without a rectifier. Size S3 frame means it fits the SIRIUS mounting rail alongside overload relays and busbar adapters.
Main circuit lands on screw terminals — solid for power wiring with ring or fork lugs. Control and auxiliary circuits use spring-loaded terminals, which means you can land the coil and aux wires without a screwdriver; strip 8 mm, push in. The built-in 1 NO + 1 NC auxiliary block covers basic feedback and interlocking without needing a separate add-on.