Siemens 1FK7084-2AF71-1QA0 SIMOTICS S 1FK7-CT 3.1 kW 20 Nm 3000 rpm Servo Motor

The Siemens 1FK7084-2AF71-1QA0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated 3.1 kW, delivering 20 Nm standstill torque (M0, 100K duty) at a 3000 rpm rated speed with an 8-pole, 6.5 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 -2AF71 code sets this motor to a 3000 rpm rated speed within the 1FK7-CT frame, the higher-speed winding versus the -2AC71 version rated to 2000 rpm at the same 20 Nm standstill torque; the trade-off shows directly in the 1.66 Nm/A torque constant here against a higher constant on the 2000 rpm winding, so more current is needed for the same torque at low speed. The -1QA0 suffix means no integrated brake, keeping moment of inertia at 32.5 kgcm2 and motor weight at 18.3 kg, lower than the brake-equipped configuration in this frame, which improves the 1.01 ms mechanical time constant for fast reversing moves. Choose this non-brake configuration for horizontal axes or applications where an external brake or a self-locking mechanism already holds position when the drive is de-energized; for vertical or gravity-loaded axes, the holding-brake version of this motor is the safer choice. The 93,000 Nm/rad torsional stiffness supports stiff, high-bandwidth position loops at the 3000 rpm rated speed.