An open belt connects two flat pulleys. The pulley diameters are 300 mm and 450 mm and the corresponding angles of Cap are 160o and 210o.
The smaller pulley runs at 200 r.p.m. The coefficient of friction between the pulley and belt is 0.25. It is taken that the belt is on the point of slipping when 3 KW is transmitted. To gain the power transmitted two alternatives are suggested, namely
(i) increasing the coefficient of friction by 10% by the application of a suitable dressing to the belt and
(ii) increasing the initial tension by 10%.
Which of these two process would be more effective ? Determine the percentage increase in power possible in each case.