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The RBE Series from Kollmorgen is a proven platform offering many years of direct drive motor solutions in various industries such as defense, semiconductor, machine tools, industrial automation, medical, and robotics. The frameless configuration is provided as a rotor and stator component that are integrated directly with the load where the same bearings which support the load also support the motor. This configuration eliminates shaft, bearings, endbells, and couplings offering reduced volume, weight, and complexity.
As the saying goes, these motors are ‘oldies but goodies’ and continue to be viable solutions where relatively high torque and low speed, pancake type motor configurations are required.
Be sure to also check out our new KBMTM series motors which represent the latest in high performance frameless brushless motor products with a more extended product range and standard options.
North America
Limited availability outside North America
Companion Products 
KBM Series Frameless

The KBM™ series offers high performance, long life and simple installation in a motor kit that can...


  • 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
Title Language(s) Date Size Email
Motors with Servostar S Catalog EN 2003 English 12 Sep 2013 334.27 KB
Kollmorgen Automationslösungen Katalog German 09 Apr 2017 11.17 MB
Technology Brief
Title Language(s) Date Size Email
Kollmorgen RBE Servostar technical publication English 26 Feb 2018 335.02 KB
Title Language(s) Date Size Email
RBE Series Motors Brochure EN 2003 English 12 Sep 2013 503.84 KB