Experience and practice with standardized acceptance test procedures for windings of rotating machinery

European Standards for rotating machines include rules for acceptance tests on high voltage winding insulation. The standard claims for dielectric loss and dielectric strength measurements and contains a thermal short time stability test of single bars or coils. This paper describes the test methods and the values of the acceptance limits. Examples will be shown how dielectric loss measurements serve successfully as a tool for maintaining uniform manufacturing results using different methods of modern insulation production. Problems, limits and benefits of applicating the described test procedures will be discussed and an international standard recommended.