# Machine Dynamics Questions and Answers – Belt Transmission Dynamometer-Froude or Throneycraft Transmission Dynamometer

This set of Machine Dynamics online test focuses on “Belt Transmission Dynamometer-Froude or Throneycraft Transmission Dynamometer”.

1. Which of the following is a function of a belt transmission dynamometer?
a) Measure the difference in tension of the belts
b) Measuring speed of an engine
c) Measuring power of an engine
d) Measuring friction

Explanation: The tangential force on the pulley which is driven is equal to the difference between the tensions in the tight and slack sides of the belt. A belt dynamometer is inserted to measure directly the difference between the tensions of the belt.

2. Belt transmission dynamometer is an absorption dynamometer.
a) True
b) False

Explanation: Belt transmission dynamometer uses the energy from the engine to do useful work, unlike absorption dynamometer where this energy gets converted into heat. Hence it is a transmission dynamometer.

3. Which of the following dynamometers work in a similar way to belt transmission dynamometer?
a) Epicyclic train dynamometer
b) Rope brake dynamometer
c) Prony brake dynamometer
d) Froude or Throneycroft Transmission Dynamometer Dynamometer

Explanation: Rope brake and Prony brake dynamometers are absorption dynamometers hence they function differently. Froude or Throneycroft Transmission Dynamometer Dynamometer is another name for belt transmission dynamometer.

4. Brake power of an engine is independent of the following quantity _______
a) Difference in band torques
b) Diameter of puller
c) Speed of engine
d) Friction

Explanation: Braking power of the engine is given by the equation:
B.P = (T1-T2)πDN/60
hence it is independent of friction.

5. For a belt transmission dynamometer, if the diameter of pully is doubled and speed of rotation is halved, then the new braking power will be ________
a) Halved
b) Doubled
d) Remain same

Explanation: Braking power of the engine is given by the equation
B.P = (T1-T2)πDN/60
if Diameter is doubled and speed is halved it will have no effect in the existing brake power.
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6. Calculate brake power from the following data:
T1 = 1500N
T2 = 800N
Diameter of pulley = 30cm
Speed of engine shaft = 600rpm
a) 6.5 kW
b) 13 kW
c) 3.2 kW
d) 7 kW

Explanation: B.P = (T1-T2)πDN/60
T1 = 1500N
T2 = 800N
D = 0.3 m
N = 600 rpm
therefore BP = 6.5 kW.

7. To prevent the rotation caused by frame, which of the following quantity is added?
a) Weight at a distance
b) Weight at the centre
c) Ball bearings
d) Welded joints

Explanation: The frame causes a rotation in an anticlockwise direction, to prevent this rotation a weight is added at a certain distance from the shaft.

8. Brake power of an engine is directly proportional to the speed of engine.
a) True
b) False

Explanation: Brake power of an engine depends on the following factors:
Difference in tension of the bands, Speed of engine and diameter of pulley.
It is given by the equation : B.P = (T1-T2)πDN/60.

Sanfoundry Global Education & Learning Series – Machine Dynamics.