Viscous Speed Governor

motion control device, door rate control, viscous speed governor

VSG's Provide Simple and Fast Door Control 

The simple, lightweight rugged construction of a viscous speed governor (VSG) provides reliable performance for numerous industrial type applications. The VSG controls the rotation of shafts and hinged loads by using a silicone-based viscous shearing technology. An inner-rotor is surrounded by silicone fluid within the unit's stationary housing. As the shaft rotates, the inner-rotor shears the silicone fluid inside providing resistance and smooth motion control. Fluid viscosity of each VSG is selected after considering variables such as the components size, weight, spring assist and desired cycle time. 
Ideally suited for the Rolling Overhead and Fire Door Control

In new and retrofit applications, a single VSG can be installed on rolling doors by simply mounting the unit to the keyed door shaft per the original door manufacturer’s instructions. Unlike noisy ratcheting devices, the VSG requires no adjustments during installation or while in-service and can control the closing and opening speed of most large overhead type doors. Multiple viscous speed governors can be used to handle over-sized doors.

Currently in use by most major door manufacturers, the patented VSG meets numerous industry standards outlined by Underwriters Labratory, Warnock Hersey and Factory Mutual. It has passed the 3-hour fire door burn test and conforms to multiple required industry standards. 
  • Safely and quietly controls rotary motion
  • Provides consistent speed control through 360º of rotation, in both directions
  • Handles linear motion via simple rack and pinion integratio
  • Industry standard shaft and keyway mounting configurations
  • Wide range of ambient operating conditions - indoor or outdoor, -40º F to +200ºF (-40º C to +95ºC)
  • Customer-specified performance over a wide range of operating RPM
  • Maintenance-free - no adjustments required