(1) Seruice factor. Select from the table for service factors [S], S,= 1.5.
(2) Design horsepower. HP,=HP,xS,=lOx1.5=15h.p.
(3) Initial chain selection. Given the design horsepower (15 h.p.), the horsepower vs speed chart [S] suggests a no. 50 single strand roller chain. The teeth number of the small sprocket is calculated. By virtue of eqns (1 I) and (12), we found n = 20.046 and n = 141.84. Select n = 20.
Therefore, a no. 50 roller chain together with a 20-tooth small sprocket is used as the initial selection.