AC servo motor
Siemens SIMOTICS S-1FK7
Long-established compact permanent-magnet servo motor range for SINAMICS S120, available in Compact, High Dynamic and High Inertia versions with a wide choice of encoders.
Key specifications
| Ingress protection | IP64 to IP65 |
|---|---|
| Rated torque | 0.08–37 Nm |
| Standstill torque (max) | 48 Nm |
| Rated speed | 2000-6000 |
| Power | 50–8,200 W |
| Frame sizes | 20, 100 mm |
| Feedback | single-turn absolute, multi-turn absolute, incremental, resolver |
| Overload | 300% |
Summarised in our own words from Siemens AG's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1 · Source 2 · Source 3
Notes on this data
Standstill torque: CT 0.2-48 Nm, HD 1.3-28 Nm, HI 3-48 Nm; rated torque 0.08-37 Nm (2022 brochure). Lifecycle: individual Generation 1 article numbers show PM410 'product cancellation' (from 01.10.2019) in Siemens Industry Mall with stated successor '1FK7 Generation 2'; the 1FK7 family (Gen 2) remains in the SINAMICS S120 portfolio. No Siemens notice found that 1FK7 as a whole is discontinued.
Specify Motion is not affiliated with Siemens AG. Siemens and SIMOTICS S-1FK7 are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Alternatives that meet or exceed these figures
Engineers often come to us with a Siemens part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Kinco's current-generation AC servo motor line, matched to the JD2 and FD5P PRO drives. Small-inertia 40-80 mm frames run at 3000 rpm on 220 V; large-inertia 130 and 180 mm frames are 1500 rpm machines reaching 47.8 Nm rated and 7.5 kW, with 23-bit multi-turn absolute encoders as standard.
| Published maximum | SIMOTICS S-1FK7 | SMK Series AC Servo Motors (SMK40S/60S… |
|---|---|---|
| Rated torque | 37 Nm | 47.8 Nm meets or exceeds |
| Peak torque | — | 119.5 Nm |
| Speed | — | 6,000 rpm |
| Power | 8,200 W | 7,500 W |
Kinco's established AC servo motor range from 40 to 180 mm frames, covering 50 W to 7.5 kW and up to 48 Nm rated torque. Standard feedback is a 2500-line incremental encoder with Hall commutation, with absolute options and a resolver on the 180 mm frame. Pairs with FD2S and CD2S drives.
| Published maximum | SIMOTICS S-1FK7 | SMH Series AC Servo Motors (SMH40S-SMH… |
|---|---|---|
| Rated torque | 37 Nm | 48 Nm meets or exceeds |
| Power | 8,200 W | 7,500 W |
A complete AGV drive wheel combining servo motor, drive, reducer, brake and polyurethane tyre in one unit on 24-60 VDC with CANopen. Three published sizes (150, 165 and 180 mm wheels) give 3.6-40 Nm rated and up to 99 Nm peak at the wheel, for mobile robots carrying up to 1 tonne.
| Published maximum | SIMOTICS S-1FK7 | iWMC Integrated Servo Wheel |
|---|---|---|
| Rated torque | 37 Nm | 40 Nm meets or exceeds |
| Peak torque | — | 99 Nm |
| Power | 8,200 W | — |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Other ac servo motor series
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