Avoiding the runaround with direct-drive rotary motion

Here's a look at the pros and cons of various direct-drive rotary systems. Manager Danaher Motion Wood Dale, Ill. Frameless DDR motors are best suited to high-performance applications where space is limited or weight is critical. Housed DDR motors are best suited for use on machines that do not include existing bearings, such as indexing and rate tables. Cartridge DDR motors are a new category of directdrive technology. They combine the performance benefits of frameless DDR motors with the ease of installation of a full-frame motor, and cost less than conventional DDR systems. Their unique bearingless design lets systems mount-and-run in less than 30 min. Direct-drive rotary (DDR) systems are available in frameless, housed, and the newly developed cartridge motor format. Although many engineers are familiar with the basics of selecting conventional servo systems, the rules are a bit different when selecting a DDR system. Most servosystems use a conventional