Siemens SIMOTICS S-1FK7 AC servo motor

Key specifications

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.

Siemens SIMOTICS S-1FK7 replacement and alternative options

Use these supply-network options as a starting point for an engineering check. We can also help source the original Siemens part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.

Servo wheel drive

Kinco iWMC Integrated Servo Wheel

Limited published data: 1 figure compared

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	—

Check this option and request pricing →View product details →

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.

What an AC servo motor is

An AC servo motor is a permanent-magnet synchronous motor designed for closed-loop control of position, speed and torque. A wound stator is driven by a servo drive with sinusoidal three-phase current, while magnets on the rotor follow the rotating field. A high-resolution encoder or resolver on the shaft feeds position back to the drive, which adjusts current many thousands of times a second. The result is precise, dynamic motion with high peak torque, typically about three times the continuous rating for short periods.

When engineers choose an AC servo motor

Choose an AC servo for machine axes needing fast, accurate motion under varying loads, such as packaging, robotics, machine tools and printing. Compared with steppers, servos keep torque at high speed and cannot silently lose position. The trade-offs are cost and set-up: a servo needs a matched drive, feedback and tuning. For simple, low-speed indexing with a steady load, a stepper may be cheaper. For very low speeds and high torque, a gearbox or direct-drive motor may be needed.

How to specify the Siemens SIMOTICS S-1FK7

Send these with your enquiry and an engineer can confirm the right SIMOTICS S-1FK7 variant or an equivalent:

• Continuous and peak torque (Nm)
• Rated and maximum speed (rpm)
• Load inertia and inertia ratio
• Supply voltage: 230 V single-phase or 400 V three-phase
• Feedback: incremental or absolute encoder, resolution (bits)
• Holding brake, IP code and shaft options
• Flange size and mounting (mm)

Common mistakes to avoid

• Sizing on peak torque without checking RMS torque over the cycle
• Ignoring load-to-motor inertia ratio, which makes tuning hard
• Forgetting the brake is for holding, not dynamic stopping
• Using a motor and drive pair that the supplier has not matched

Typical applications

Siemens SIMOTICS S-1FK7: frequently asked questions

Further reading: How to select a servo motor · Servo vs stepper · Servo and stepper motors

Other ac servo motor series