1PH8 - The Compact, Synchronous Servomotor for High-Power Applications

1PH8 Motors

Siemens 1PH8 synchronous servo motors excel in demanding, high-power applications. Their high-power density allows a small footprint and supplies high torque at medium rotor inertia. The synchronous servo design generates 30 to 40 percent more torque and power than its already compact 1PH8 induction cousin, which is about 30% smaller than standard NEMA or IEC induction motors.

The servo design of the 1PH8 has the same outer dimensions as the induction design allowing simple future upgrades. Servo motors 1PH8 are available in IP rating 55 and 65 with a high overload capability (up to 3 times rated torque) and rotatable connectors or terminal boxes.

Special Features and Options

Key Benefits



Forced-ventilated or water-cooled

Absolute or incremental encoders

All the advantages of Siemens electronic nameplate


Keyed or plain shaft

Horizontal or vertical mounting

Bearing options for increased cantilever forces

or increased speed range

Efficient and secure power cabling

Freedom for the OEMs R&D Department
The 1PH8 servomotor offers 100% interface compatibility to the 1PH8 high performance induction motor, allowing simple power upgrades from the induction design to the higher power dense servo design

Outstanding Production Quality
Very high motion control capability through high radial eccentricity; very low torque ripple and high resolution encoder systems

Easy-to-Install / Easy-to-Service
Through rotatable connectors and terminal boxes, electronic nameplate and free choice of air flow direction

Space Saving
With the cooling options, forced-ventilated and water-cooled, the power density is outstanding in the high-power servo market

Technical Data

Shaft heights

132 to 225 mm

Rated speed *

700 – 3,600 rpm

Rated power *

21 - 416 HP / 15.7 - 310 kW

Rated torque *

69 - 1,217 lb-ft / 94 - 1,650 Nm

* Depending on specific motor version and type

Need more Technical?

Typical Applications

  • Converting, e.g. coilers, winders or cross cutters

  • Machine tools, e.g. main spindles

  • Metalforming, e.g. main drive at servo presses

  • Plastics, e.g. screws on electrical injection molding machines

  • Printing Systems, e.g. print cylinders

  • Textiles, e.g. fleece handling or web stretching

  • All types of high-power and/or high-dynamic path and speed control applications

Information About Other Siemens Servo Motors

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