Graham Ring Roller Variable Speed Transmission

Due to increasing demand for our core competency product, the Graham Ring Roller will no longer be offered by Motor Specialty Inc.

If you are interested in purchasing the complete inventory and intellectual property, please contact

As Motor Specialty Inc. phases out this product, any remaining inventory you need to maintain for your existing units may be available for a limited time through


Product Overview

If you require precise speed control, constant torque and reliability in a mechanical package then the Ring Roller traction drive is your answer.

Quick Specs

Cast iron or aluminum
Precision ball
C.W., C.C.W., Reversible
Shaft Diameter
N29 series .625"-.750"150 series .750"-1.125"
Shaft Extension
Single or double
N29 series 0-8750 150 series 0-2800
Horsepower Range
N29 series 1/6 HP thru 1/4 HP 150 series 1/4 HP thru 1.5 HP


  • Thirty-five turn micrometer hand-wheel
  • Unmatched accuracy
  • Overload protection
  • Wide choice of controls
  • Linear speed setting mechanism
  • Rolling motion
  • Torque producing elements made of ball bearing steel operate in mist of traction lube in sealed
  • housing
  • Infinite speed range
  • Full torque available to zero RPM
  • Control ring contacts tapered rollers
  • Completely mechanical
  • Wide choice of input/output configurations


  • Multiple input speeds
  • Multiple speed reducer options
  • Speed corrector
  • Built in motor
  • Mechanical reversing
  • Spring loading


  • Precise speed setting to 1 part in 3500
  • Will hold speed .1 to 1% of maximum speed under stead load
  • No pulsing or drifting
  • Protects itself and driven machine against damage
  • Mechanical, pneumatic, & electrical controls for manual, remote or automatic speed control
  • Standard controls gives near linear speed change. Exact linear control optional.
  • High efficiency
  • Low maintenance. Nothing to adjust or replace at frequent intervals
  • Can operate at any output speed from full speed forward, to zero RPM, to full speed reverse
  • No need to oversize drive for low speed operation
  • Step-less speed control
  • Efficient operation over wide temperature range-30°F to 120°F ambient
  • Safe in hazardous environments when used with explosion proof motor
  • Input shaft, C-Face, integral motor designs to meet all requirements
  • Right angle reducers, helical reducers, and spur gear reducers and increasers provide the
  • output torque and speed range required



  • Welding machines
  • Position welders
  • In-Feed attachment for wood-working machines
  • Vibration testing machines
  • Feeder systems and conveyors
  • Business forms printing presses
  • Lapping machines
  • Camera tracker
  • Boiler tube cleaners

Technical Drawings

Series N29 Dimensions

N29 Series Drawing

Series 150 Dimensions

150 Series Drawing


Motor Performance Curves

Series N29 Performance Specs

N29 Series Performance

Series 150 Performance Specs

150 Series Performance