SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING When o is divided by 2T and multiplied by 60, we obtain rpm(n).Iherefore m=n/n=r/r,=d/d 6.10 That is, the speed ratio of two cylinders in rolling contact is equal to the inverse ratio of their radii or diameters. in consistent units The drawback inherent to a friction drive. such as that described above, is that it is liable to slip when power of any consequence is transmitted. It can be used only for very small torque applications, such as phonograph turntable drives and the like diameter直径SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING When ω is divided by 2π and multiplied by 60,we obtain rpm (n). Therefore, mω = n1 /n2 = r 2 /r1 = d2 /d1 6.10 That is, the speed ratio of two cylinders in rolling contact is equal to the inverse ratio of their radii or diameters, in consistent units. The drawback inherent to a friction drive, such as that described above, is that it is liable to slip when power of any consequence is transmitted. It can be used only for very small torque applications, such as phonograph turntable drives and the like. diameter 直径