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Testing Laboratory

QA and R&D

Most suppliers of rotating machines and motors apply partial discharge and loss factor measurements in-line with their quality assurance program and final acceptance tests. Measurement results can help to improve the system design or can help researches in finding suitable insulation materials.

Testing Laboratory

The quality of the stator winding insulation system should be verified according to the following brief description of the test procedure.

The test requires an AC power source capable of supplying PD-free 50 or 60Hz variable voltage up to at least the rated line-to-ground voltage of the insulation system under test. Partial discharge measurements are taken in voltage steps up to the rated line-to-ground voltage of the insulation system to measure the discharge inception voltage (DIV) and the discharge extinction voltage (DEV). The maximum PD magnitude at line-to-ground voltage should be less than 50pC.


IEEE 268-2000
"IEEE Recommend Practice for Measurement of Power Factor Tip-Up of Electric Machinery Stator Coil Insulation"

"Test of insulation of bars and coils of high-voltage machines"

IEC 60894-1987
"Guide for a test procedure for the measurement of loss tangent of coils and bars for machine windings"

Connection Diagram with ICMflex

ICMflex connected to a single stator bar under test