Understanding The Vibration Forces In Induction Motors.

LecturePg. 67-76Squirrel cage induction motors have been used extensively in industry for over 50 years. While it appears that vibration problems are more pronounced nowadays, certain basic construction features have always existed and have created considerable difficulty from the initial stages of motor development. As induction motor theory has never changed, the electromechanical forcing functions have always existed and created vibration problems. In fact, some of the most complete and best references on vibration in induction motors were written 30 to 40 years ago. It appears, however, that only recently has the induction motor been critically reviewed by mechanical engineers and rotating machinery specialists. Motors are now being treated for what they are-extremely complex rotating machines having not only the associated mechanical forces, but electromagnetic and electromechanical forces as well. The basic operating principles of motors are discussed as well as the lateral vibration forcing functions encountered when troubleshooting motor vibration problems. All motors described herein are squirrel cage, polyphase, 60Hz design