AC servo motor
Siemens SIMOTICS S-1FT2 AC servo motor
Higher-performance sibling of the 1FK2 with forced-ventilation options, higher-resolution encoders and IP67 sealing, aimed at demanding motion on SINAMICS S210 and S120/S220.
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Need Siemens parts, a replacement or another suitable option? Send your part number or describe what the machine needs to do. We connect your requirement with experienced UK engineering and procurement support to help you get the right products, pricing and supply options. Your matched provider can take the enquiry through quotation and ordering to delivery and after-sales support.
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- One enquiry for components, complete axes and ongoing support
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What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Ingress protection | IP67 |
|---|---|
| Rated torque | 0.4–58 Nm |
| Rated speed | up to 6000 |
| Power | 260–15,700 W |
| Feedback | absolute encoder up to 26-bit resolution, DRIVE-CLiQ |
| Cooling | natural cooling or forced ventilation |
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
Notes on this data
Torque and power from the 1FK2/1FT2 product page key-specs table. Shaft heights, peak torque and max speed not published on pages checked.
Specify Motion is not affiliated with Siemens AG. Siemens and SIMOTICS S-1FT2 are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Engineer support
Speak to our engineers about your project
Our experienced engineers are on hand, ready to help with your project. Whether you need the Siemens SIMOTICS S-1FT2 itself, help sourcing it, or a modified or custom design built around your load, speed and space, tell us what the machine has to do and we'll come back with the right option.
- Help sourcing SIMOTICS S-1FT2 and spares for installed machines
- Modified and custom designs when a catalogue part doesn't fit
- Complete axis: motor, drive, gearing and feedback matched together
Typical applications
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-1FT2
Send these with your enquiry and an engineer can confirm the right SIMOTICS S-1FT2 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
Siemens SIMOTICS S-1FT2: frequently asked questions
Can you help replace Siemens SIMOTICS S-1FT2 or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the Siemens SIMOTICS S-1FT2?
Higher-performance sibling of the 1FK2 with forced-ventilation options, higher-resolution encoders and IP67 sealing, aimed at demanding motion on SINAMICS S210 and S120/S220. Published series figures include rated torque 0.4 Nm, rated torque 58 Nm, power 260 W, power 15,700 W. It is made by Siemens AG; Specify Motion can help source it or propose an equivalent.
Who makes the Siemens SIMOTICS S-1FT2?
The Siemens SIMOTICS S-1FT2 is made by Siemens (Siemens AG) and is listed here for engineers comparing options. Specify Motion is not affiliated with Siemens AG; brand names are used only to identify the product.
What is the rated torque of the Siemens SIMOTICS S-1FT2?
The published series minimum rated torque is 0.4 Nm. Individual models and sizes in the SIMOTICS S-1FT2 range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Siemens SIMOTICS S-1FT2?
We can assess suitable replacement options. Our engineers can review the original model and propose options for your load, speed and environment. An engineer confirms the fit against your application before recommending anything.
What is the inertia ratio in servo sizing?
The inertia ratio compares the load inertia reflected to the motor shaft with the motor's rotor inertia. High ratios make the axis harder to tune and slower to settle. Many engineers aim for below about 10:1, and lower for highly dynamic axes, using a gearbox to reduce reflected inertia where needed.
Do AC servo motors need an absolute encoder?
Not always. Incremental encoders need a homing routine after power-up, which is acceptable on many machines. Absolute encoders know their position at power-on, avoiding homing, which saves time and suits robots and multi-axis machines. Multi-turn absolute encoders track turns even when power is off.
Further reading: How to select a servo motor · Servo vs stepper · Servo and stepper motors
Other ac servo motor series
Engineer support
Our engineers are ready to help with your project
Tell us about your project and how you use the Siemens SIMOTICS S-1FT2: the load, speed, duty and environment. An experienced engineer will review it and reply, normally within one working day.
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