Siemens 3RT2017-1VB42 SIRIUS 3RT contactors, 3-pole, up to 250 kW. Siemens 3RT2017-1VB42 is the exact printed commercial reference for a contactor / contactor accessory in the SIRIUS 3RT Contactors range. Siemens' official product description is: power contactor, AC-3e/AC-3, 12 A, 5.5 kW / 400 V, 3-pole, 24 V DC, 0.85-1.85* Uc, with integrated diode, auxiliary contacts: 1 NC, screw terminal, frame size: S00, no auxiliary switch can be added.