SIRIUS 3RT23 4-Pole Contactors Siemens SIRIUS 3RT23 Contactors are 4-pole AC-1 contactors with current up to 160A. The Siemens SIRIUS 3RT23 Contactors are designed for switching motors and feature screw or spring-load terminals. 3RT23 4-Pole Contactors offer high contact reliability, prolonged endurance, and usability in extreme conditions that characterize SIRIUS 2 devices.