For a given fractional change of speed. If the displacement of the sleeve is high, then the governor is said to be
A Governor is said to be sensitive when it readily responds to a small change of speed. The movement of the sleeve for a fractional change of speed is measure of sensitivity.
Effect of friction, at the sleeve of a centrifugal governor is to make it
Friction at the sleeve makes the governor less sensitive.
The term “effort of governor” refers to
The effort of a governor is the mean force exerted at the sleeve for a given percentage change of speed.
Which one of the following statements is correct? A governor will be stable if the radius of rotation of the balls
For stable governor
F = Ar - B
and F = mrω2
For a governor running at constant speed, what is the value of the force acting on the sleeve
When governor is running at constant speed, then the net force acting of sleeve is zero.
The problem of hunting of a centrifugal governor becomes very acute when the governor becomes
Sensitiveness of a governor is a desirable quality. However, if a governor is too sensitive, it may fluctuate continuously above and below the mean position, it is called hunting of governor.
The nature of the governors is shown by the graph between radius (r) of rotation and controlling force (f). Which of the following is an isochronous governor?.
For isochronous governor
f = ar
Hence plot will be
In a governor, the controlling force curve shows a relationship between
Controlling force curve is plotted between controlling force at y-axis and radius of rotation at x-axis.
The angular speed of a watt’s governor when its height is 20 cm, will be equal to
where, h = height of governor
N = RPM
In a spring-controlled governor the controlling force curve is straight line. The balls are 400 mm apart when the controlling force is 1600 N and they are 240 mm apart when the force is 800 N. To make the governor isochronous the initial tension must be increased by
The controlling force curve of a spring controlled governor is straight line and thus can be expressed as
f = ar+ b
when f = 1600 N, r = 400 mm
when f = 800 N, r = 240 mm
1600 = a(0.4) + b ...(i)
800 = a(0.24) + b ...(ii)
By solving (i) and (ii) we get
a = 5000 N/m
b = -400 N
To make the governor isochronous, the controlling force line must pass through the origin. This is possible only if the initial tension is increased by 400 N.