WATT GOVERNER

WATT GOVERNER

The simplest form of a centrifugal governor is a Watt governor, as shown in Fig.  It is

basically a conical pendulum with links attached to a sleeve of negligible mass. The arms of the

governor may be connected to the spindle in the following three ways :

1. The pivot P, may be on the spindle axis as shown in Fig. 18.2 (a).

2. The pivot P, may be offset from the spindle axis and the arms when produced intersect at

O, as shown in Fig. 

3. The pivot P, may be offset, but the arms cross the axis at O, as shown in below Fig

ω = Angular velocity of the arm and ball about the spindle axis in rad/s,
r = Radius of the path of rotation of the ball i.e. horizontal distance from the centre of the ball to the spindle axis in metres,
FC = Centrifugal force acting on the ball in newtons = m.ω2.r, and
h = Height of the governor in metres.

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It is assumed that the weight of the arms, links and the sleeve are negligible as compared to

the weight of the balls. Now, 

the ball is in equilibrium under the action of

1. the centrifugal force (FC) acting on the ball,

 2. the tension (T) in the arm, and 3. the weight

(w) of the bal

Taking moments about point O, we have;

FC × h  =  w × r  =  m.g.r

(or)

m.ω2.r.h = m.g.r

 (or)

 h = g /ω2

When g is expressed in m/s2 and ω in rad/s, then h is in metres. If N is the speed in r.p.m., 

then

$$ω = {2 π N\over 60}$$

$$h = {9.81\over (2πN/60)}.$$

$$ = {895\over N^2}.$$