Assume that the motor and coupling characteristics represented in Figure 19.11 correspond to a well engineered installation incorporating a 10-kW, 1750-rpm motor. A similar but smaller installation is being considered, for which the power requirements are 50 percent less. Accordingly, a 5-kW, 1750-rpm motor and a smaller, but geometrically similar, fluid coupling will be used. By what factor could the diameter of the fluid coupling be reduced? If the 5-kW power source used in the new installation rotates 3500 rpm, by what factor could the coupling diameter be reduced?
