Two pulleys on two shafts are connected by a flat belt. The driving pulley is 250 mm in diameter and runs at 150 rpm. The speed of the driven pulley is 90 rpm. The belt is 120 mm wide, 5 mm thick and weighs 1000 kg/m3. Assuming a slip of 2% between the belt and each pulley, determine the diameter of the driven pulley and the total effective slip in the belt drive.
Answers
Answer:
1. Two pulleys on two shafts are connected by a flat belt. The driving pulley is 250 mm in diameter and runs at 150 rpm. The speed of the driven pulley is to be 90 rpm. The belt is 120 mm wide, 5 mm thick and weighs 1000 kg/m3. Assuming a slip of 2%
between the belt and each pulley, determine the diameter of the driven pulley. Also,
find the total effective slip.
2. Two pulleys mounted on two parallel shafts that are 2 m apart are connected by a crossed belt drive. The diameters of the two pulleys are 500 mm and 240 mm. Find
the length of the belt and the angle of contact between the belt and each pulley. Also, find the power transmitted if the larger pulley rotates at 180 rpm and the maximum permissible tension in the belt is 900 N. The coefficient of friction between the belt and the pulley is 0.28.
3) A belt having a cross-section of 100mm x10 mm transmits maximum power with an angle of lap 160° on the smaller pulley. The density of the belt material is 1000 kg/m3
and the coefficient of friction is 0.25. The permissible tension in the belt is 1.5
N/mm2. Determine the maximum power transmitted by the belt.
4. A V-belt weighting 1.6 kg/m has an area of cross-section of 750 mm2. The angle of
lap is 165° on the smaller pulley which has a groove angle of 40°, and µ= 0.12. The
maximum safe stress in the belt is 9.5 N/mm2. What is the power that can be
transmitted by the belt at a speed of 20 m/s.
5. A rope drive transmits 40 kW at 120 rpm by using 15 ropes. The angle of lap on the
smaller pulley which is 300 mm in diameter is 165°. Coefficient of friction is 0.25 and
the angle of groove is 40°. The rope weighs (50 x 10-6) G2 kg per metre length of rope and working tension is limited to 0.14G2 N where G is the girth(circumference) of rope in mm. Determine the initial tension and the diameter of each rope.
6. A chain drive is used for speed reduction from 240 rpm to 110 rpm. The number of
teeth on the driving sprocket is 22. The centre to centre between the two sprockets is 540 mm and the pitch circle diameter of the driven sprocket is 480 mm. Determine the number of teeth on the driven sprocket, pitch and length of the chain.
7. Part 1: The following data in Table 1 refer to an open belt drive. Taking into
consideration the centrifugal tension, determine the following parameters when the linear velocity of the belt is 10 m/s.
(a) The initial tension.
(b) The power transmitted.
Parameters
Values
Diameter of the larger pulley
400 mm
Diameter of the smaller pulley
200 mm
Distance between the two pulleys
Explanation: