 myself, Sachin Rathore working as assistant professor in mechanical engineering department from Washington stop technology solar room. Today, we will see the next part of the selection of the belt that is the selection of the belt part 9 from the course machine design 1. The learning outcome of this students will able to design the flat belt from the manufacturing catalog. So, this is the problem statement for the flat belt drive so that the sentence is or the problem statement is it is required to select the flat belt drive to connect the two transmitting shaft rotating at 800 rpm and the 400 rpm respectively. So, we have to convert the speed from 800 rpm to the 400 rpm. The center to center distance between the shaft is approximately 3 meter and the belt drive is open type. The power transmitting by the belt is 30 kilowatt and the load correction factor is 1.3. The belt should operate at velocity between 17.8 to 22.9 meter per second. The power transmitting capacity of the belt per mm width per ply at 180 arc of contact and the at the belt velocity of 5.08 meter per second is 0.0147 kilowatt. So, just they have considers one there are the two types of the belt one is a 4th belt and the high speed belt from that they have selected the belt. Select the preferred diameter and the specify the belt. So, this is the problem statement from which we have to select the proper type of the belt. So, this is a given data that is the type of the belt is flat belt drive the input speed output speeds center distance load correction factor and the power they had given us. So, from this data we have to specify the belt. So, in that step number one calculate the pitch diameter of the pulley. So, they are given as the range of the belt which is ranging from 17.5 to 22.9. So, just we have considered the belt velocity is 18 meter per second by considering this belt velocity calculate the diameter of the pulley that we are knowing the equations v is equal to pi d n by 60. As we are knowing the speed of the input shaft and the output shaft calculate the value of small d just put the value of n1 is 800 mm velocity is 18 mm calculate the small d. So, we are getting the small d value is 429.72 mm. So, we have to check whether that diameter of the pulley is in the standard data book or not. So, we had observed that it is not in that book standard data. So, you can select the diameter of the pulley as 450 mm. So, from the standard manufacturing data take d is equal to 450 mm. So, in the next step you can calculate the diameter of the larger pulley by using the equation n1 by n2 is equal to capital D by small bd. As the speed is inversely proportional to the diameters you can easily calculate the diameter of the larger pulley. So, by putting the value of small d n1 and n2 you will get the value of capital D as 900 mm that also available in the design data book. So, you can directly take capital D is equal to 900 mm. Now, the step number 2 calculate the corrected velocity of the belt. The corrected velocity of the belt is calculated by using the equations v corrected is equal to pi d n1 by 60. So, as in the previous slide we had considered the velocity of the belt is 18 meter per second and we had calculated the diameter of the smaller pulley. Now, I have taken the diameter of the smaller pulley from the design data book put that value of this diameter of the smaller pulley you will get the corrected velocity. So, the corrected velocity we are getting as 18.849 meter per second. Now, step number 3 calculate the load correction factor FA. So, FA value they had given us 1.3. So, you can pause this video and you can think about this if they had not given us the load correction factor then how to find out the load correction factor. So, you can think about this. Now, the step number 4 calculate the angle of contact for the smaller pulley. So, we are having this equation by using this equation you can calculate the alpha s value just put the value of capital D small d and c you will get the value of alpha s. Now, by knowing the value of the wrap angle you have to calculate the contact factor fd that is arc of contact factor from the manufacturing data book. So, this is the manufacturing data from which we have to calculate the value of arc of contact factor. So, you have to use the interpolation formula to calculate the value of factor. So, if you observe this table you have to calculate the value of the factor at the angle of 171.397 so, which is lying in between 170 and 180 we have to calculate the factor the value of this factor at 171.397. So, just I will explain how to use the interpolation formula for finding the factor. So, this is a very simple method to find out the factor. So, just consider one scale on which the two values are there that is a value 171.80 the factor for the 170 is 1.04 just I have written as it is and the 180 angle the factor is 1 and we have to calculate the factor at 171.397 just I have considered that factor is x. So, you have to use the interpolation formula so, how to use that interpolation formula see that. So, in the left hand side 171.397 minus 170 divided by x minus 1.04 just I will use the pointer so, 171.397 minus 170 divided by x minus 1.04 is equal to 180 minus 170 divided by 1 minus 1.04 so, only one unknown is there in that equation so, you can easily find out that factor. So, just I have rewritten this equation you can easily calculate the value of the x. So, the x value we are getting as 1.034 this x value is nothing but the factor fd the arc of contact factor fd for the angle of 171.39. So, like this way we are calculating the value of the fd is equal to 1.034 in the step number 6 calculate the design power. So, design power is calculated by using this equation pd is equal to p into fa into fd put this value you will get the value of design power. So, the design power we are getting 40.326 kilowatt the step number 7 calculate the power rating of the belt means the power transmitting capacity of the belt. So, the power transmitting capacity of the belt is calculated by using this equation. So, already they are given us for a speed of 5.08 meter per second the power is 0.0147 for the fort belt. So, we have to calculate the power rating for your actual belt. So, for the actual belt the v corrected velocity is 18.849 put this value you will get power rating of your actual belt. So, the power rating we are getting as 0.05454 kilowatt. Now, the next step step number 8 calculate the width of the belt. So, the width of the belt we are calculating by using this equation w is equal to pd divided by pr into number of the ply as we are knowing the value of the pd and pr we have to calculate the w and number of the ply by using this table. So, this is nothing but the number of the ply number of the ply is 1, 2, 3, 4 just I have taken an example how to show the number of the ply and this is nothing but the total width. So, you have to find out number of the ply and the width. So, we are having these two parameter pd and pr, the pd and pr we are knowing just put the number of the ply value. So, if I have considered the number of the ply is 3 put here the value is 3 calculate the w calculate the w. So, we are getting the value of the width w is equal to 246.46 mm. We have to check this first row the value is not ranging the value of the width for the 3 ply is up to 76. So, we cannot consider the 3 ply. Now, go for the 4 ply just put the value of the number of the ply is equal to 4 calculate the width. So, here width we are getting as a 184. So, check out the second row if the number of the ply is 4 the value is up to 152. So, 184 is not lying. So, do not consider the number of the ply as 4. Now, the next value number of the ply is equal to 5 find out the width if the width is 147.87 we are getting just check out the fourth row sorry third row if the ply is 5 the value is up to 152. So, we can consider the width of the belt is 152 and the number of the ply is 5. So, like this way we are calculating the width is 152 and the number of the ply is 5. So, in the step number 9 calculate the length of the bed length of the open bed drive is calculate a bios in this equation. So, just put the value of capital D small d and c you will get the length of the open builder. So, the final solutions will be the design solutions will be obtained as diameter of the smaller pulley is 450, diameter of the larger pulley is 900, the width of the belt is 152 mm, number of the ply is 5 and the length of the belt is 8137.45 mm. So, this is a belt specification according to this solution. So, I have taken the reference as a design of machine element by VB Bhandari. Thank you.