The Siemens 3RT7027-1AL20 is a Size S0 3-pole contactor from the SIRUS series, rated for AC-3 and AC-3e duty up to 690 V.
The AC-3 rated operational current is 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V — these are the motor-switching currents you size the contactor for, not the resistive (AC-1) rating. The maximum switching frequency is 800 operations per hour under AC-3 duty and 250/h under AC-4 (plugging/inching), so it handles moderate-speed cycling but isn't for high-frequency servo or reversing applications. Coil power draw is 0.72 W during closing and 0.24 W holding. Pollution degree 3.
Dimensions are 45 mm wide, 85.5 mm high, 91 mm deep — fits standard S0 footprint.
Protection coordination and wiring
For type 2 coordination, use gL/gG NH 3NA fuses rated 50 A. For type 1 coordination, use 125 A fuses.