The Siemens 1FK2104-4AK11-0MB0 is a SIMOTICS S-1FK2 HD servo motor out of the 1FK2 servomotor family built to drive SINAMICS S120 converters, with a stall torque M0 of 1.27 Nm and a rated output PN of 0.6 kW at nN=6000 rpm on a 380-480 V bus — or 0.4 kW at 3000 rpm when run on a 200-240 V bus (cites:). The holding brake, IP65 sealing, a cylindrical shaft D19x40 mm, and an AM22DQC 22-bit + 12-bit multiturn absolute encoder via DRIVE-CLiQ (connector size M17) are the headline integrator-facing features (cites:).
Ratings that drive the fit decision
The 0.6 kW / 6000 rpm / 380-480 V point is the high-speed envelope that the application profile (high-speed indexing, small-part feeders) needs to land on (cites:); the lower 0.4 kW / 3000 rpm on 200-240 V is the same motor on a North-American 240 V or Asian 200 V supply, so the BOM does not need a voltage-special variant to cover both mains (cites:). Stall torque M0=1.27 Nm sets the lower bound of the torque envelope at zero speed — the sizing conversation starts here, not the rated point (cites:).
Mechanical and feedback integration
The shaft is a cylindrical D19x40 mm profile rather than a keyed or conical variant — gearbox and coupling selection must match the D19 journal and the 40 mm length, and any radial load has to be checked against the shaft-bearing limit in the datasheet drawing (cites:). Feedback is AM22DQC, a 22-bit single-turn + 12-bit multiturn absolute encoder carried over DRIVE-CLiQ; the wiring is the matching M17 power connector plus M17 DRIVE-CLiQ plug, so the cabinet-side harness has to terminate at M17, not the older M23 encoder style used on 1FK7-class predecessors (cites:).
Compliance and documentation posture
The part is declared RoHS-compliant since 01-07-2006 and carries the standard REACH Art. 33 disclosure obligation — Siemens publishes the candidate-list update through the dedicated Reach Information channel (cites:, cites:). Export-control classification is AL:N / ECCN:N_CNDU, which is the routine no-license-required posture for this class and does not gate a standard cross-border shipment (cites:).