The Siemens SIRIUS 3RT2027-2AL20-ZX95 is a Size S0 power contactor — the S0 frame is the mid-size in the SIRIUS contactor family, balancing panel space with a 45 mm width and a 97 mm depth. It mounts via screw fixing or snap-on onto 35 mm standard mounting rail per DIN EN 60715; the mounting position allows +/-180° rotation on a vertical surface and can be tilted forward/backward by +/- 22.5° on a vertical surface. The coil connection uses spring-type terminals — no screw tightening needed, which speeds wiring in panel builds. Auxiliary switch is included.
Switching frequency and endurance by duty class
The contactor's maximum switching frequency depends on the utilization category: AC-1 (resistive loads) at 1 000 cycles/hour, AC-2 (slip-ring motors) at 750 cycles/hour, AC-3 (squirrel-cage motors) at 750 cycles/hour, AC-3e (enhanced AC-3) also at 750 cycles/hour, and AC-4 (inching/plugging) at 250 cycles/hour. The lower AC-4 limit reflects the higher electrical stress during inching duty.
Wire range and environmental limits
Solid and stranded wire both accept 1... 10 mm²; the auxiliary contact terminals accept 2x (0.5... 2.5 mm²) solid or stranded. The arcing time is 10... 10 ms at AC.