Siemens 1FK7100-2AC71-1QA0 SIMOTICS S 1FK7-CT 3.0 kW 18 Nm 2000 rpm Servo Motor

The Siemens 1FK7100-2AC71-1QA0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated 3.0 kW, delivering 18 Nm standstill torque (M0, 100K duty) at a 2000 rpm rated speed with an 8-pole, 7.1 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 larger-frame motor to a 2000 rpm rated speed within the 1FK7-CT line, against the -2AF71 winding rated to 3000 rpm; the 2.14 Nm/A torque constant on this 2000 rpm winding gives more torque per amp than the higher-speed alternative, useful where drive current is the limiting factor. The -1QA0 suffix means no integrated brake, so moment of inertia stays at 54.0 kgcm2 and motor weight at 17.6 kg, lower than the brake-equipped configuration in the same frame, which keeps the 1.95 ms mechanical time constant as low as this design allows. Choose this non-brake configuration for horizontal axes or where an external holding mechanism is already in place; for vertical or gravity-loaded axes, the holding-brake version of this motor is the correct choice to prevent drift on an E-stop. The 183,000 Nm/rad torsional stiffness is the highest in this comparison set, supporting stiff position loops even with the larger 100 mm shaft height frame.