(1) Service factor. Select from the table for service factors [8], S, = 1.0.
(2) Design horsepower. HP, = HP, x S, = 3010.746 x 1.0 = 40.2145 h.p.
(3) Initial chain selection. Given the design horsepower, the horsepower vs speed chart [8] suggests a no. 80 single strand roller chain. The teeth number of the small sprocket is calculated and found to be n = 20. Therefore, a no. 80 roller chain together with a 20-tooth
small sprocket is used as the initial selection.
(4) Selection of large sprockef. Given the velocity ratio, V, = 750/250, the teeth number of the large sprocket is then N = V, x 20 = 60. Note that the teeth number of the two sprockets in Ref. [lo] were I7 and 51 owing to dmerent values of ratings.
(5) Spare limifation. With the input of the sprocket diameters, it was found that the initial selection for chain 80 with n = 20 does not meet the specified space limit. An alternate design was then made.