(Solved): 2. In a multiple vee belt drive shown in Figure B4 the included angle of the vee is \( 120^{\circ} ...

2. In a multiple vee belt drive shown in Figure B4 the included angle of the vee is \( 120^{\circ} \), the diameters of pulleys are \( D_{1}=450 \mathrm{~mm} \) and \( D_{2}=200 \mathrm{~mm} \). The distance between the pulleys centres \( \mathrm{d}=0.5 \mathrm{~m} \). Each belt has a cross-section area of \( 100 \mathrm{~mm}^{2} \), the mass per meter length \( 100 \mathrm{~g} / \mathrm{m} \) and the maximum allowable stress in the belt material \( \sigma=4 \mathrm{~N} / \mathrm{mm}^{2} \). The coefficient of friction between the pulley and the belt is \( 0.35 \). The driver pulley \( \mathrm{D}_{2} \) rotates at \( 1600 \mathrm{rpm} \) in clockwise direction. Determine: a) the tight and slack sides of the belt, b) the driver pulley lap angle, (3 marks) (3 marks) c) the effective coefficient of friction between the pulleys and the belts, (3 marks) d) the angular velocity of the driven pulley and the belt speed, (4 marks) e) the maximum allowable tension in the belt, (4 marks) f) the extra tension due to centrifugal effect in the high speed drive, (4 marks) g) the minimum number of the belts to transmit power of \( 18 \mathrm{~kW} \) without slip. (4 marks) Total 25 marks