Siemens 1FK7084-2AC71-1QA0 SIMOTICS S 1FK7-CT 3.1 kW 20 Nm 2000 rpm Servo Motor

The Siemens 1FK7084-2AC71-1QA0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated 3.1 kW with 20 Nm standstill torque at 100K and a 2,000 rpm rated speed. It runs on a 600 V DC link, uses natural cooling, and carries an IP64 enclosure with an absolute 20-bit single-turn DRIVE-CLiQ encoder (AS20DQI). This variant ships without a holding brake.

Selection Notes

At 20 Nm this is the highest standstill torque in the 1FK7-CT family covered here, built on the same 80 mm shaft height as the 12 Nm and 16 Nm frames but with a longer lamination stack — 32.500 kgcm² inertia and 18.3 kg net weight versus 15.6-15.9 kg for the 16 Nm motors. The 93,000 Nm/rad torsional stiffness and 2.36 Nm/A torque constant fit direct-drive or low-ratio geared axes that need high torque at moderate speed rather than high rpm.

Applications

Typical use: heavier direct-coupled axes on machine tools, winders, and material-handling equipment where 20 Nm standstill torque at 2,000 rpm matches the load without a gearbox.