FOREWORD The standards appearing in this publication have been developed by the Motor and Generator Section and approved for publication as Standards of the National Electrical Manufacturers Association. They are intended to assist users in the proper Selection and application of motors and generators. These standards are revised periodically to provide for changes in user needs, advances in technology, and changing economic trends. All persons having experience in the selection, use or manufacture of electric motors and generators are encouraged to submit recommendations that will improye the usefulness of these standards.