Basics of Configuring Drives

The key to many motion applications is in sizing the drive components lying between the motor and load. Here are the basics. • The overall design determines basic drive mechanisms. • Motor-gearing combinations typically determine gear reduction ratios and other key parameters. Wikipedia page on gear ratios, It can be difficult to specify drive components that transform power from a motor into a form that is useful for the load. The overall design may dictate use of basic drive mechanisms such as spindles, gearing, or belts. But the motor or motor/gearing combination determines the parameters that are optimum. These parameters can include spindle pitch, gear reduction ratios, and other factors. Drive-system components, in turn, influence the dynamic response, control quality, and positioning accuracy. The promulgation of automation has thrust many engineers into the role of specifying drive parameters. So it can be useful to examine the equations that describe how drives transform one form of mechanical power into another: Linear-motion drives convert a motor's rotary motion into linear motion. Rotary drives convert motor rotation into some other kind of rotation, typically either at a different speed ratio or with an intermittent motion. Linear drives include leadscrews, conveyor belts, cranes, and rack-and-pinion drives. Rotary drives include all types of gearheads and (toothed) belt constructions. It typically takes just a few parameters to describe the conversion of power in such drives. The more common ones include reduction ratios, efficiency calculations, mass inertia, and a description of mechanical play. indicates the ratio between the angular velocity at the input ω ) and the angular velocity at the output  ω ). In linear motion drives, we define the reduction ratio as the ratio between ω ) and the output velocity . For calculating input speed the following equations apply: • i π/30 • n The reduction ratio for rotary transformation is given as a dimensionless ratio between two speeds of rotation.