Proell Governor

The Proell governor has the balls at B and C to the extension of the links DF and EG, as shown in Figure 14.6(a). The arm PF and GQ are pivoted at P and Q, respectively. Consider the free body diagram of half of the governor as shown in Figure 14.6(b). The instantaneous centre (I) lies on intersection of the line PA produced and the line from D drawn perpendicular to the axis.

Figure 14.6 Force Analysis in Proell Governor

Taking moment about instantaneous centre (I), we get

Multiplying and dividing by FM

Putting

Example 14.4: A Proell governor has equal arms length of 400 mm. The upper and lower ends of the arms are pivoted on the axis of the governor. The extension arms of the lower links are each 60 mm long and parallel to the axis when the radii of rotation of the balls are 180 and 240 mm. The mass of each ball is 10 kg and mass of the central load is 80 kg. Determine the range of the speed of the governor.

Solution:

Let

N₁ = minimum speed at radius r₁ = 180 mm

N₂ = minimum speed at radius r₂ = 240 mm

 

Now at minimum speed,

At maximum speed,