کنفرانس بین المللی ماشین و محرکه های الکتریکی

صفحه اصلی / The 5th International Conference on Electrical Machines and Drives

Pre-Impregnation High Voltage Testing of Random-Wound Stators for Early Detection of Insulation Defects

نویسندگان :

Ali Alaeddini¹ Fatemeh Ramezani² Mahdi Khademnahvi³ Mansour Torabi⁴

1- R&D Department, MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj, Iran 2- R&D Department, MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj, Iran 3- R&D Department, MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj, Iran 4- R&D Department, MAPNA Generator Engineering and Manufacturing Co. (PARS) Karaj, Iran

کلمات کلیدی :

Random-wound stator،Electrical insulation،Pre-impregnation high-voltage test،Global vacuum pressure impregnation (GVPI)

چکیده :

Random-wound stator windings are widely used in low-voltage rotating machines, where insulation integrity is critical to ensuring long-term reliability. Conventional pre-impregnation tests such as insulation resistance, polarization index, and surge tests are often insufficient for identifying hidden defects in random-wound stator ground insulation that may be temporarily covered after resin impregnation. This study investigates the application of a reduced-level DC high voltage test as a diagnostic method ro detect insulation defects prior to impregnation without overstressing the insulation. Two permanent magnet synchronous motors rated at 80 kW and 46 kW were tested under controlled factory conditions. While conventional tests did not reveal any faults, the pre-impregnation DC high voltage test successfully detected hidden defects, including damaged wire enamel and misplaced wires, which were confirmed through visual inspection. After localized repair, the stators passed both pre- and post-impregnation tests, validating the effectiveness of this approach. The findings demonstrated that pre-impregnation DC high voltage testing can serve as a practical and reliable quality assurance method, reducing the risk of costly post-impregnation failures and improving the long-term service life of random-wound machines.