1. Controlling force in the porter governors is due to which of the following components?
a) Spring
b) Weight of sleeve
c) Weight of governor
d) Piston effort
Explanation: The controlling force is provided by the weight of the sleeve and balls as in Porter governor and by the spring and weight as in Hartnell governor
2. Controlling force in the Hartnell governors is due to which of the following components?
a) Weight of balls
b) Weight of sleeve
c) Spring
d) Piston effort
Explanation: The controlling force is provided by the weight of the sleeve and balls in case of Porter governor and by the spring and weight in case of Hartnell governor
3. If the mass of the ball is 7.5 kg and the controlling force is 200N with an angular velocity of 100 rpm, find the radius.
a) 24 cm
b) 28 cm
c) 30 cm
d) 20 cm
Explanation: F=m.ω2.r
200 = 7.5 (2πx100/60)2.r
Therefore r = 0.243m.
4. If the mass of the ball is 25 kg and the controlling force is 450 N with an angular velocity of 150 rpm, find the radius.
a) 7.2 cm
b) 7.9 cm
c) 8.3 cm
d) 12.3 cm
Explanation: F = m.ω2.r
450 = 25 (2πx150/60)2.r
18 = 246.7.r
Therefore r = 0.072m.
5. Control force diagram enables to examine stability and sensitivity of the governor.
a) True
b) False
Explanation: When the graph is drawn between the controlling force (Fc) as y-axis and radius of rotation of the balls (r) as x-axis, then the graph obtained is known as controlling force diagram of the governor. This diagram enables the stability and sensitiveness of the governor to be examined and also shows clearly the effect of friction.
6. Which of the following quantities cannot be examined from controlling force diagram?
a) Sensitivity
b) Stability
c) Effect of friction
d) Power of governor
Explanation: The graph between the controlling force (Fc) as y-axis and radius of rotation of the balls (r) as x-axis is known as controlling force diagram. This diagram enables us to examine the stability and sensitiveness of the governor along with the effect of friction.
7. Let r represent the radius of rotation, then for stability of a spring controlled governor, which of the following relation regarding controlling force is true? (a, b are constants)
a) Fc = ar-b
b) Fc = ar +b
c) Fc = ar
d) Fc = a
Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the stability of spring controlled governors is given by the following equation:
Fc = ar-b.
8. If the line intersects the Controlling force axis in positive direction in the controlling force diagram of the spring controlled governor, then it is stable.
a) True
b) False
Explanation: . If the line intersects the Controlling force axis in negative direction in the controlling force diagram of the spring controlled governor, then it is stable.
Fc = ar-b
9. Let r represent the radius of rotation, then for an unstable spring controlled governor, which of the following relation regarding controlling force is true? (a,b are constants)
a) Fc = ar-b
b) Fc = ar +b
c) Fc = ar
d) Fc = a
Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the unstability of spring controlled governors is given by the following equation:
Fc = ar+b.
10. Let r represent the radius of rotation, then for an isochronous spring controlled governor, which of the following relation regarding controlling force is true? (a,b are constants)
a) Fc = ar-b
b) Fc = ar +b
c) Fc = ar
d) Fc = a
Explanation: The relation between the controlling force (FC) and the radius of rotation (r) for the instability of spring controlled governors is given by the following equation:
Fc = ar