SIRIUS power contactor, size S0 — 3RT6027-1BM40
The Siemens 3RT6027-1BM40 is a SIRIUS power contactor in the size S0 frame, rated for motor switching up to 27.5 kW at 400 V at 60 °C ambient. It mounts on a 35 mm DIN rail per DIN EN 50022 with a snap-on or screw fastening, and takes 45 mm of panel width. The screw-type terminals on both main and auxiliary circuits accept 2x (0.5 to 2.5 mm²) solid or stranded, or AWG 16 to 8 for the main contacts. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C.
What the ratings mean for your panel
The AC-3e maximum switching frequency of 750 cycles per hour governs motor starting duty — this contactor handles frequent starts without overheating, but the AC-4 maximum of 250 1/h applies when plugging or inching. The 27.5 kW at 400 V at 60 °C is the real-world motor power you can switch in a warm cabinet; at 690 V it reaches 47.5 kW. The 10 million mechanical cycles typical life means this contactor outlasts most equipment it controls, making it a strong candidate for a critical spare.
Panel integration notes
At 45 mm wide and 107 mm deep, this size S0 contactor fits standard 35 mm DIN rail. Side-by-side mounting is permitted, so you can gang multiple units without spacing. The screw terminals are rated for pollution degree 3, suitable for industrial control panels. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when fitting into tight enclosures.