Review Questions

REVIEW QUESTIONS

1. Enumerate the various types of belts used for the transmission of power.

2. Discuss the merits and demerits of belt, rope and chain drives for transmission of power.

3. Explain the following terms: (i) Slip; and (ii) Creep in belts.

4. Deduce an expression for the length of a belt in (i) an open belt drive; and (ii) a cross belt drive.

5. Derive the expression for the total length of the belt required to connect any two pulleys of radius r1 and r2 through open belt drive. Take the distance between axes of pulleys as 'd'.

[Hint: Refer Section 8.9.1]

[A.U., Nov/Dec 2009]

6. Show that the tension ratio in a flat belt drive is

[A.U., Nov/Dec 2011]

[Hint: Refer Section 8.10.1]

7. Derive an expression for the centrifugal tension in a belt drive and show that it is equal to one third the maximum tension for maximum power transmission.

8. What is the effect of centrifugal tension on power transmission by flat belt?

9. Establish the tension ratio for V-belt or rope drive.

10. Prove or disprove the following statement: "A V-belt drive with same coefficient of friction and angle of wrap as a flat-belt drive will transmit less than flat-belt drive".

[Ans. A V-belt drive with same μ and θ as a flat-belt drive will transmit more power than the flat-belt drive, because of the wedging action in the grooved pulleys. Note that tension ratio for V-belt drive is T1/T2 = eμ. θ cosec β . Say, with a wedging angle 2β = 38° and assumed values of θ = 165° and μ = 0.3, the limiting ratio of tensions for V-belt drive is 5.865 as against 1.778 for flat-belts. Thus the V-belt drive will transmit more power than that of the flat-belt drive with same μ and θ.]