 Hello everyone, myself Sachin Rathod working as an assistant professor in Mechanical Engineering Department from Alchemy Stop Technology, Svalapur. Today we are discussing the bit that is the selection of the belt part 8 from the course machine design one. The learning outcome of this session is the learner will be able to design the V belt from the manufacturing catalog. So just we will consider one case study from which you will get how to select the V belt for particular application mm. So this is the given data, the power is 5 kilowatt, the speed of the input shaft is 1440 rpm, the speed of output shaft is 970 rpm, the centre distance between two shaft is 500 rpm, sorry the centre distance between the two shaft is 500 mm, the service is 24 hours per day we have to use and the diameter of the smaller pulley is 150 mm. So as per the given data, we have to find out the proper type of the V belt. So we will go by the steps, the step number one is determine the correction factor according to the service from the table. So from these tables, we have to find out the service factor. So the service factor totally depend upon the applications. So the power is 5 kilowatt, the speed of the input shaft that is the speed of the faster shaft is 1440 rpm and we have to run the fan for 24 hours per day. So we have to run the compressor and we are having the normal torque which is having the service of 24 hours per day. So from these tables, you can easily find out the value of the FA is 1.2. So we are getting the procedure how to find out the service factor from this manufacturing catalog. The step number two, find out the design power for the V belt. So the design power for the V belts were calculating by using the equation FA into transmitted power. So FA value as we are getting from the previous slide is 1.2 and the transmitted power is 5 kilowatt. So design power is equal to 6 kilowatt. Step number three, determine the cross section of the belt based on design power and higher speed of the shaft in rpm from the following table. So we have to find out which cross section of the V belt we have to consider for the given application of the shaft. So this is a table I have taken from the manufacturing data book. So in which the horizontal line or the horizontal axis indicating the design power and the vertical line that the y axis is indicating the speed of the faster shaft. So as the design power is 6 kilowatt, the design power is 6 kilowatt, so we have to draw one vertical line, so like this way. So this line is indicating the 6 kilowatt power and the speed of the faster shaft is 1440 rpm. So we have to draw one horizontal line that is indicating the speed of 1440 rpm. So we have to find out the intersecting point, the intersecting point is lying at this junction. It indicates that we have to use the B belt drive. So it is ranging in between these two lines. So the B belts we have selected, the cross section of the belt we have to select as a B belt. Next the dimension of the cross section. So as we have selected the B belt, the cross sections that is the pitch width, so in these figures we are getting the pitch width, the top width and the height of the V belt. So we are getting the pitch width is 14, the nominal top width is 17 mm and the nominal height is 11 mm. So these are the cross section of the V belt that is having the B type cross sections, so which is having the 40 degree angle. And from these tables you are getting the recommanded minimum pitch diameter of the pulley is 200 and the permissible minimum pitch diameter is 125. So you can select the value in between these two, either you can select 125 or you can go for the 200 mm or you can select in between these two values. So you have to prefer the pitch diameter of the pulley. So as we have selected the B belt, we can select the width, so we can select the preferred pitch diameter as 125 or 200 or you can select in between these two values. That if I selected 150, it is okay, the pulley will not get fell. Either you can select 125, 130 to 140, 150, 160, 170, 180, 190 or 200. So that I have selected the diameter of the pulley, that is smaller pulley is 150 mm. So small d is equal to 150 mm. Now calculate the value of the diameter of the larger pulley that is the capital D as we are knowing the value of the n1, n2 and small d, put that value you will get the value of capital D. So that is a 222.68 mm. So we have to find out the diameter of the larger pulley from the standard data book. So this is a catalog from which we have to select the diameter of the larger pulley. As we are getting the diameter of the larger pulley is 222.68, we have to check out whether the diameter is there in that table or not. So it is not there in this table. So you can go for 224 instead of the 222.64, you can prefer the diameter of the larger pulley as 224 mm. So capital D is equal to 224 mm. So calculate the pitch length of the belt. So the pitch length of the open belt drive, we can calculate by using this equation. Just put the value of capital D, small d and c in this equation, you will get the length of the open belt drive. That we are getting the length of the open belt drive is 1590.22 mm. In the step number 6, select the standard pitch length. As we are designing the V belt drive, we have to find out the standard pitch length. So you can pause this video and you can think about this, why it is necessary to select the standard pitch length. As we are getting the length of the belt is 1590.22, why it is necessary to find out the standard pitch length. So this is a standard table from which we have to select the pitch length of the belt. So we have selected the B belt drive and as we are getting the length of the belt is 1590.22, so we have selected the length of the belt is 1560 mm. So this is a standard length we have selected, that is L is equal to 1560 mm. So you have to find out the correct center distance c by considering the standard pitch length. So as we are changing the pitch length, definitely the center distance will get changed. So again we have to put down the value of length and calculate the c distance. So as we are changing the length, we have selected the length from the standard data book, put that value of the length and again find out the center distance. So you will get the center distance is equal to 484.85 mm. So determine the correction factor for the belt pitch length in the step number 8. So this is a table from the manufacturing data book, calculate the correction factor. So as we are having the B belt which is having the length 15060 mm, the load or the belt pitch length correction factor is 0.92. So we are getting the value of the FC is 0.92. In the step number 9, calculate the angle of contact for the smaller pulley. So we are having the equation for finding the wrap angle alphas. Put the value of capital D, small d and c, you will get the wrap angle is equal to 171.25 degree or we can consider it is a 171 degree. So from the standard data book, calculate the contact factor FD. So this is a table from which we have to calculate the arc of contact factor FD. So as we are having the alpha else is 171, so you are the correction factor FD is 0.98. So in the step number 11, calculate the power rating of the belt from the manufacturing data book. So as we are knowing the speed of the faster shaft is 1440 rpm, so the speed of the faster shaft is 1440 rpm and the diameter of the smaller pulley is 150 mm. So you can select it as a 3.83. Again we have to check out the additional power increment of the belt that is a speed ratio. The speed ratio we are getting by the equation speed of the input shaft divided by the speed of the output shaft we are getting 1.485, so it comes here that is a 1.35 to the 1.51. So the value is 0.36, so these two value we are getting for finding the power rating. So the power rating is equal to 3.83 plus 0.36, so total power rating is 4.19 kW. So by knowing that power rating and the power you can calculate the number of the belt. So number of the belts we are calculating by using the equation P into F A divided by P R into F C into F D. Just put that value you will get the number of the belt is 1.59. So you have to take the whole number therefore the number of the belts required are the two. So the final design solution will be obtained as the diameter of the smaller pulley is 150 mm, diameter of the larger pulley capital D is equal to 224 mm. The belt specification is B1560 LP V belt, the number of the belts required are two. The center distance C is equal to 484.85 mm. So these are the design solutions for your the particular application. So I have taken a reference as a design of machine element book authored by VB Bhandari. Thank you.