KEVOS® MAKEOS · Mechanics

Fly-ball (Porter) Governor Height and Sensitivity

At what height does this fly-ball governor run at this speed, and how sensitive is it?

Height of a loaded (Porter) or simple conical-pendulum fly-ball governor at a given speed, the sleeve movement between two speeds, and the coefficient of speed variation used to compare governor sensitiveness.

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How this tool works

Inputs, units and where to find them

InputUnitTypical source
Mass of one ballkgMass of one fly-ball.
Central load (0 = simple governor)kgMass of the central sliding load on the spindle (Porter governor); 0 for an unloaded Watt governor.
Governor speedrpmSpeed of the governor spindle.
Maximum speed of the control rangerpmHighest speed within the governor’s range of action.
Minimum speed of the control rangerpmLowest speed within the range.

Method and formulas

  1. h = (g ÷ ω²) × (c + w) ÷ w — the handbook’s h = 2933 ÷ n² × (c + w) ÷ w in feet; c = 0 gives the simple pendulum governor.
  2. Coefficient of speed variation C = (M − M₁) ÷ m, with m the mean speed.
  3. Example: 2 kg balls with a 10 kg load run at a height of 134.14 mm at 200 rpm.

Limitations

  • Arms pivoted on the spindle axis with equal arm and link lengths; friction is neglected.
  • Spring-loaded (Hartnell) governors need a spring force balance instead.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Check the sleeve travel of a centrifugal governor
  • Compare loaded and simple governors for a speed range
  • Restore or replicate a mechanical speed regulator

Who it is for

  • Machine designers
  • Maintenance engineers
  • Automation engineers

What you get

  • Governor height at the speed
  • Sleeve height change across the range
  • Coefficient of speed variation

Interpreting the result

  • A larger central load raises the working speed for the same height and makes the governor usable at higher speeds.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3453–3455. Topic reference; no source tables or recommended settings are reproduced.

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Open the Fly-ball (Porter) Governor Height and Sensitivity calculator