Test Methods of Rotating Machines

Experimental results and development of testing apparatus and methods are described in three Sections without items overlapped with other papers in this issue. The first Section contains non-destructive test methods which include an automatic measurement of tan6, an automatic insulation analyzer (AIA) and a portable tester using trapezoidal voltage application. The second Section contains experimental results using very low frequency voltage as a high-potential proof test. The last Section contains experimental results of a potential grading method at electrode edges which is effective for dielectric breakdown tests of HV coil insulation performed in air.