An 8 mm thick leather open belt connects two flat pulleys. The smaller pulley is 30 cm diameter and runs at 200 r.p.m. The angle of lap of this pulley is 1600, and the coefficient of friction between the belt and the pulley is 0.25. The belt is on the point of slipping when 3.5 h.p. is transmitted Safe working stress in the belt material is 16 kg. per sq. cm. Determine the required width of the belt for 20% overload capacity. Initial tension may be taken equal to mean of the driving tensions. Make a neat proportionate sketch of the pulley.
It is proposed to increase the power transmitting capacity of the drive by adopting one of the following alternatives:
(a) by increasing initial tension by 10%
(b) by increasing the coefficient of friction to 0.3 by applying a dressing to the belt.
Examine the two alternatives and recommend the one which, you think, will be more effective. How much power would the drive transmit adopting either of the alternatives?