Siemens 1FK7101-2AC71-1QA0 SIMOTICS S 1FK7-CT 4.3 kW 27 Nm 2000 rpm Servo Motor

The Siemens 1FK7101-2AC71-1QA0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated 4.3 kW, delivering 27 Nm standstill torque (M0, 100K duty) at a 2000 rpm rated speed with an 8-pole, 9.7 A design. It is naturally cooled, IMB 5 flange-mounted, and fitted with an absolute single-turn 20-bit encoder on a DRIVE-CLiQ interface, IP64-rated, without a holding brake.

Selection Notes

The -2AC71 code sets this motor to a 2000 rpm rated speed within the 1FK7-CT line, against the -2AF71 winding rated to 3000 rpm at the same 27 Nm standstill torque; the 2.15 Nm/A torque constant on this 2000 rpm winding gives more torque per amp than the higher-speed alternative. The -1QA0 suffix means no integrated brake, so moment of inertia stays at 79.0 kgcm2 and motor weight at 23.0 kg, lower than the brake-equipped configuration in this frame, which helps keep the 1.62 ms mechanical time constant responsive. Choose this non-brake configuration for horizontal axes or where an external holding mechanism already covers position retention when power is removed; for vertical or gravity-loaded axes, the holding-brake version of this motor is the correct choice. The 164,000 Nm/rad torsional stiffness and 60-minute thermal time constant, higher than the smaller 1FK7084 and 1FK7100 frames in this comparison, support sustained torque output at this power level.