Graham Ring Roller Variable Speed Transmission


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

N29 Series Drawing


150 Series Drawing


Motor Performance Curves

N29 Series Performance


150 Series Performance