1. When the governor is too sensitive, then which of the following process occurs?
a) Hunting
b) More stability
c) Less variation in speed
d) Increased steadiness
Explanation: Hunting is a process in which the speed of the engine is continuously fluctuating above and below the mean speed. This is something which happens when a governor is too sensitive.
2. The effort of a governor is the _________ force exerted at the sleeve for a given percentage change of speed.
a) Maximum
b) Minimum
c) Mean
d) Reciprocal of
Explanation: The effort of a governor is the mean force exerted at the sleeve for a given percentage change of speed or lift of the sleeve.
3. When there is no force on the sleeve, then the governor must be running steadily.
a) True
b) False
Explanation: When a governor is running steadily then it is under the condition that it experiences no force on its sleeve. Forces acting on the sleeve results in change of speed of the governor
4. Resistance in a sleeve which results in opposing the motion is caused by _______
a) Change of speed
b) Change of weight
c) Isochronism
d) Change in type of governor
Explanation: When the speed at which the governor is undergoing motion changes, there is a resistance at the sleeve which opposes its motion.
5. Power of a governor depends on which of the following factor?
a) Mean effort
b) Maximum effort
c) Minimum effort
d) Weight of the engine
Explanation: The power of a governor is the work done at the sleeve for a given percentage change of speed. It is the product of the mean value of the effort and the distance through which the sleeve moves.
6. Find the power of the governor if the Mean effort is 50 N and sleeve lift is 100 mm.
a) 5N-m
b) 25N-m
c) 250N-mm
d) 50N-mm
Explanation: Power is given by
(mean effort) x (sleeve lift)
= 50×0.1 N-m
= 5N-m.
7. If the sleeve lift is 80 mm and Power generated by the governor is 6 N-m, then find the mean effort.
a) 7.5 N
b) 15 N
c) 20 N
d) 30 N
Explanation: Power is given by
mean effort x sleeve lift
6 = 0.8xmean effort
6/0.8 = 7.5 N.
8. If the mean effort is doubled and the sleeve lift is halved, If P was the original power then what will be the power post the changes?
a) 2P
b) P
c) 4P
d) P/2
Explanation: Power is given by:
mean effort x sleeve lift
since power is directly proportional to the sleeve lift and mean effort, hence doubling one factor and reducing the other to half has no effect on the power.
9. Power of a governor is the work done by the sleeve for a given percentage change in speed.
a) True
b) False
Explanation: Power of the governor is the work done at the sleeve for a given percentage change of speed. It is important to note that the work should be done at the sleeve and not at any other part of the governor.
10. For a porter governor, Each arm has a length of 250mm and pivoted on the axis of rotation. Sleeves carry a mass of 25kg and each ball’s mass is 5Kg. Radius of rotation: 150mm at the beginning of lift and 200mm at the maximum speed of governor. Find range in speed neglecting friction in rpm.
a) 25
b) 35
c) 45
d) 15
Explanation: For minimum position, h1 = 200 mm
N12= (m+M)/m x 895/h1 = 26850 rpm
For maximum position,
h2=150 mm
N22 = (m+M)/m x 895/h2 = 35800 rpm
Range = N2 – N1 = 25 rpm