Drive selection memo
Siemens SINAMICS G120C order code 6SL3210-1KE21-3UB0 is a compact variable-frequency drive rated for 5.5 kW output with a 150% overload capability for 3 seconds — enough headroom for short-duration load spikes on pumps, fans, or small conveyors without oversizing the frame. The input accepts 380-480 VAC three-phase, 47-63 Hz, unfiltered, so it connects directly to standard European or North American industrial mains without an external line filter for most installations. Built-in Safe Torque Off (STO) meets SIL 3 / PL e, eliminating the need for a separate safety relay in many guarding circuits — the drive itself breaks torque when the safety signal drops. Fieldbus is integrated as USS or MODBUS RTU on the same terminal block, so no option card is required for basic PLC communication. The I/O complement — 6 digital inputs, 2 digital outputs, 1 analog input, 1 analog output — covers start/stop, speed reference, and status feedback for a standalone machine cell.