The Siemens 3RA1436-8XB20-1BB4 is a SIRIUS wye-delta contactor assembly — three contactors of size S2 pre-configured on a common mounting plate, wired for star-delta motor starting. The assembly mounts via screw fixing on a vertical surface, rotatable ±180° and tiltable ±30° front-to-back, which gives panel builders flexibility in enclosure layout without derating the contactors. The main current circuit is 3-pole with screw-type terminals, and the assembly accepts an auxiliary switch extension. Side-by-side mounting clearance is 0 mm, so the assembly can be packed tight against neighbouring gear without additional spacing.
At 690 V the same duty drops to 63 kW, and at 500 V it is 55 kW. The overload relay adjustment range spans 0.8 to 1.1 times the full-scale value at 50 Hz, and 0.85 to 1.1 at 60 Hz, so the thermal protection can be dialled to match the motor nameplate. The control supply is 24 V DC only — no AC coil option on this variant. The surge suppressor is omitted from the assembly, so if your panel has inductive loads on the same control transformer, plan for a separate suppression diode or RC snubber across the coil.