Factors Contributing to Improving Electric Service by Means of High-Speed Switching and Utilization of Stored Energy

The quality of electric service as reflected through variations in motor speeds resulting principally from voltage surges is about as important to many manufacturing processes as is the continuity of such service. This paper sets forth the effects of voltage surges on an extremely speed-sensitive manufacturing process and describes how the effect can be minimized to the extent of becoming harmless. Test data are given which show the effects of voltage surges, of varying duration and magnitude, on the process, and the voltage surge is shown engraved in the finished product as the purchaser sees it. The maximum tolerable driving motor speed variation, without impairment to the product, is established and means are described for preventing a greater variation irrespective of the voltage surge intensity. An alarm system is described which is capable of instantly responding when variations in speed exceed tolerable limits. Use of a synchronous condenser, to supply energy during the interim of severe voltage disturbances or brief power failures, is effective in preventing motor-speed variations from exceeding the tolerable limits. These and other recent improvements will provide highly reliable electric service for the requirements of those manufacturing proccesses which are very exacting as to speed variations.