The Siemens 3RT1045-1AL20-ZX95 is a SIRIUS power contactor in the S3 frame size, rated for 45 kW at 500 V in AC-3 duty — that's the motor-switching current class, so it handles a 45 kW induction motor on a 500 V line. Side-by-side mounting is allowed, which keeps panel width tight when you're stacking multiple contactors for a multi-motor group.
Fastens with screws or snaps onto 35 mm and 75 mm standard mounting rail — that's the standard DIN-rail footprint, so it drops into any IEC panel without adapters. The main circuit uses screw-type terminals; solid wire accepts 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and up to 2x (0.75 to 4 mm²). Stranded connections go up to 2x (10 to 50 mm²).
Duty ratings and mechanical life
AC-4 (plugging/reversing) maxes at 300 ops/h.
Dimensions and mounting clearances
Height 146 mm, width 70 mm, depth 139 mm — that's the envelope for the S3 frame.