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RBE Series Frameless Motors

The RBE Series is a proven direct-drive platform, with many years of application success in defense, semiconductor, machine tools, industrial automation, medical, robotics and other industries. The frameless configuration is supplied as a rotor and stator component that can be integrated directly into the machine, using the same bearings to support both the load and the motor. This design eliminates shaft, bearings, endbells, and couplings to reduce volume, weight and complexity.

Limited availability outside North America



  • 10 frame sizes from 21.3mm to 239mm OD
  • Continuous torque range from .01 N-m to 38 N-m
  • Peak torque range from .03 N-m to 200 N-m
  • Speeds up to 35,000 rpm
  • Standard and custom windings to match speed/torque performance requirements
  • RBEH housed models come with stainless steel shafts and can include any combination of Hall sensors, encoder or resolver as rotor position feedback devices
  • RBE frameless models use the load’s own shaft and bearings, and can include integral Hall sensors, and additional position feedback devices such as encoders or resolvers can be added as separate components


  • Low cogging for smooth low-speed rotation
  • Brushless design allows significant reductions in rotor inertia and increases in acceleration
  • Improved cooling and efficiency provides increased performance in a wide variety of operating conditions
  • Frameless configuration reduces machine size and maintenance requirements since load and motor use same set of bearings

Get Started

Count on Kollmorgen support to help you design and build a successful machine and keep it reliably productive, anywhere in the world. Our co-engineering experts will work with you to tailor a perfect-fit solution for your motion requirements.

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Technology Brief
Title Language(s) Date Size
Kollmorgen RBE Servostar technical publication English 26 Feb 2018 335.02 KB Copy URL
Title Language(s) Date Size
Motors with Servostar S Catalog EN 2003 English 12 Sep 2013 334.27 KB Copy URL
Title Language(s) Date Size
RBE Series Motors Brochure EN 2003 English 12 Sep 2013 503.84 KB Copy URL
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