1FK7 – The Most Compact, Cost-Effective, Synchronous Servomotor

Featuring natural cooling and a rugged, maintenance-free design, the 1FK7 synchronous servo motor is ideal for motion control applications where a final position must be reached very quickly with ultimate precision. High Dynamic models have the ability to speed up and slow down very quickly. With high torques of up to 108 Newton meters and a particularly favorable torque-inertia ratio, the 1FK7 motor achieves a very high dynamic response, which means shortened cycles and less wear on the motor, resulting in decreased machine downtime. Servo motors 1FK7 are available in IP ratings 64 to 67 with a high overload capability (up to 3 times rated torque) and rotatable connectors.

A Motor in a Month

There are now two programs for getting you a new or replacement SIMOTICS S-1FK7 servomotor in 4 weeks.

Siemens still offers over 100,000 1FK7 Generation 2 servomotor configurations in 4 weeks or less via drop ship to addresses in the USA.
> Learn more here

There's now a new program, SIMOTICS S-1FK7 preferred servomotors, featuring a more focused selection available for all countries with delivery in less than four weeks.

> This flyer tells you about this and other benefits of the 1FK7 Preferred program

Special Features and Options

Key Attributes



Absolute or incremental encoders

All the advantages of Siemens electronic

nameplate DRIVE-CLiQ

Available with or without holding brake

400 / 480V or 230V ratings

Keyed or plain shaft

Geared with planetary, bevel, offset-shaft,

worm, or helical gears

Available in Compact, High Dynamic or High Inertia design models

1FK7 Compact (CT) servomotors

Space-saving installation through very high-power density

Exceptional short design

Wide range of motors in shaft heights 20 to 100 mm

1FK7 High Dynamic (HD) servomotors


Intended for highly-dynamic applications with

low-load inertia

Most rapid acceleration due to low rotor inertia

Higher productivity du to shortened cycle times

1FK7 High-Inertia (HI) servomotors



Very good production quality in applications with

high-load inertia

Very good control capability of high-load inertias

or widely varying load inertias

For constant speed or interpolating applications with high-load inertia

Technical Data

Compact (CT)

High Dynamic (HD)

High Inertia (HI)

Shaft Heights

20 – 100 mm

36 – 80 mm

48 – 80 mm

Rated speed *

2,000 – 6,000 rpm

2,000 – 6,000 rpm

2,000 – 6,000 rpm

Rated power *

0.07 – 11 HP / 0.05 – 8.2 KW

0.8 - 5.1 HP / 0.6 - 3.8 kW

0.5 - 4.2 HP / 0.4 - 3.1 kW

Rated torque *

0.06 - 27 lb-ft / 0.08 - 37 Nm

0.7 - 13 lb-ft / 0.9 - 18 Nm

0.9 - 11 lb-ft / 1.2 - 15 Nm

* Depending on specific motor version and type

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