Siemens 1FK7101-2AC71-1QB0 SIMOTICS S 1FK7-CT 4.3 kW 27 Nm 2000 rpm Holding Brake Servo Motor

The Siemens 1FK7101-2AC71-1QB0 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 plus an integrated holding brake, for IP64-rated position retention on vertical axes.

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 favors low-speed torque density. The -1QB0 suffix adds the integrated holding brake, which raises moment of inertia to 87.0 kgcm2 and motor weight to 27.5 kg compared with the non-brake configuration in this frame, so the added inertia needs to be folded into the drive's tuning at this 1.62 ms mechanical time constant. Pick this brake configuration for vertical or gravity-loaded axes that must hold position when the servo drive de-energizes; on a horizontal axis without a fail-safe holding requirement, the non-brake version in the same frame carries less inertia. The 116,000 Nm/rad torsional stiffness and 60-minute thermal time constant still support sustained-torque duty cycles once the brake mass is accounted for.