An overhung cast iron pulley transmits 7.5 kW at 400 r.p.m. The belt drive is vertical and the angle of wrap may be taken as 180°. Find: (a) Diameter of the pulley. The density of cast iron is 7200...

Extracted text: An overhung cast iron pulley transmits 7.5 kW at 400 r.p.m. The belt drive is vertical and the angle of wrap may be taken as 180°. Find: (a) Diameter of the pulley. The density of cast iron is 7200 kg/m3. (b) Width of the belt, if the coefficient of friction between the belt and the pulley is 0.25. (c) Diameter of the shaft, if the distance of the pulley centre line from the nearest bearing is 300 mm (d) Dimensions of the key for securing the pulley on to the shaft. (e) Size of the arms six in number. The section of the arms may be taken as elliptical, the major axis being twice the minor axis. The following stresses may be taken for design purposes: Shaft and key: Tension – 80 MPa Shear – 50 MPa : Tension – 2.5 MPa : Tension – 4.5 MPa : Tension – 15 MPa Belt Pulley rim Pulley arms