Download Lab Experiment: Determining Friction Coefficient of Belt and Pulley (EDJ28503) and more Thesis Machine Design in PDF only on Docsity! Laboratory Manual EDJ28503 – Machine Mechanism Elements LABORATORY MANUAL EDJ 28503 MACHINE MECHANISM ELEMENTS LAB 2 Belt Friction NAME : MATRIC NO. : DATE : LECTURER : MRS. RAHATON AZIRAH BINTI RAMLI PLV : MRS. SHARIFAH NURUL HUSNA BINTI SYED HANAPI Mark: Laboratory Manual EDJ28503 – Machine Mechanism Elements Experiment: Belt Friction Objective: To determine the coefficient of friction between belt and pulley. Apparatus: 1 Belt friction apparatus. 2 Set of weights • The apparatus consists of a pulley with groove to anchor v and flat belt. • One groove is provided for applying torque to the system. • Two types of belts are provided, one Vee and the other a flat belt. Stud Load that causes tension at one end of the belt Pulley Load to generate torque Belt under test Holes to anchor stud Laboratory Manual EDJ28503 – Machine Mechanism Elements Intergrating Equation (3) gives loge (T1 / T2) = μθ or (T1 / T2) = eμθ …………………..(4) The torque exerted on the driving pulley = (T1 – T2) * r1………………….(5) For the this experiment T1 is the equal to the load applied at the hook end T2 is obtained from equation (5) By plotting the graph of loge (T1 / T2) versus θ the coefficient μ can be found. Laboratory Manual EDJ28503 – Machine Mechanism Elements Procedure: 1 Decide on the angle θ and record the angle 2 Screw the stud to the mounting hole corresponding to this angle. 3 Hang a load hanger at the hook end of the belt 4 Wound a cord round the pulley to apply torque to the system 5 Hang a load hanger at the free end of the cord 6 Apply tension to the belt by applying load on the hanger. 7 Place small weights on the torque hanger and observed the pulley. If the pulley does not move, remove the load from the hanger. Increase the load and place it again on the hanger. Repeat until the load on the hanger is able to rotate the pulley. 8 To get a more accurate result, adjust the last load on the hanger that causes the pulley to rotate (decrease the load) and record the smallest load that causes the rotation. This is the load that provide the torque just sufficient to overcome friction of the belt. 9 Record the tension in the belt and the weight on the torque hanger. 10 Increase the tension in the belt and repeat step 8 to 11 for a few more load increment. 11 Choose another angle θ and repeat the experiment. Laboratory Manual EDJ28503 – Machine Mechanism Elements Results: 1. Flat belt Radius of the pulley = 75 mm Record your observations in Table 1 below Table 1: θ = radians Angle of Contact, θ radian Load on Belt T1 N Load on Torque Hanger, WT N 60° 5 10 15 20 75° 5 10 15 20 90° 5 10 15 20 105° 5 10 15 20 For each angle of contact plot the graph of T1 versus WT Obtain the slope of each graph to the average belt tension T1 and T2 for each case Torque = WT * r …… …..(1) Where WT = load on the torque hanger r = radius of the pulley. Torque = (T1 – T2) * r …………..(2) Therefore, WT * r = (T1 – T2) * r Or T2 = (T1 – WT) From the plot of T1 versus WT, the slope of the graph represent T1 per unit WT Therefore, slope = (T1 / 1.0) Or average tension in the belt, T1 = slope of graph and WT = 1.0 Hence average tension in the belt, T2 = slope of graph – 1.0
