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Question 2 [60 marks] Figure 1 below shows a conveyor belt has been driven by a motor through a compound gearbox which has an efficiency of 88%. The gears have a module of 8 mm and pressure angle of 20°. Gear 1 and 3 have 20 teeth each while gear 2 and 4 have 75 teeth each. The conveyor drum requires a torque of 200 Nm and rotates at approximately 100 rpm. The conveyor belt operates for 12 hours per day and experiences minor and light shock load. You are required to find the following: (a) A suitable 3-phase Brook Crompton motor to drive the conveyor belt. (b) A suitable Fenaflex coupling to connect the motor and the gearbox input shaft. The tangential, separating and total forces acting between gear 1 and 2. (c) (d) The diameter of the drum shaft, given that the total pull on the conveyor belt amounts to 1000 N and the separating force on gear 4 is 333 N as shown on the free body diagram in Figure 1.2 below. Assume that the drum shaft has a keyway and commercial steel is used. (e) A pair of NTN deep groove ball bearings for the drum shaft, if the shaft diameter is 40mm. The minimum bearing life (L10h) required is 50,000 hours. Assume that there is axial load of 120N acting on the bearings. Gear 2 Gear 3- 150 mm, 600 mm Ø30mm- Convevor Drum 1000N Tension due to conveyor Drum Shaft Belt Motor Coupling- Figure 1.1 Figure 1.2 Gear 1- Gear 4 Bearing A- 333 N 1000 N th C A D R₁ Re 2 本 Bearing A