The operation of induction motor affected by stress factor causes insulation degradation. This degradation can be observed from changes in insulation characteristics, including electrical, physical, and chemical. This study aimed to evaluate the insulation resistance (IR) and polarization index (PI) since the induction motor condition was good until burned out. Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX) testing was also carried out to analyze changes in microstructure, morphological characteristics, and chemical composition in stator windings. In addition, X-ray powder diffraction (XRD) testing was presented to validate that the damaged insulation was caused by the given stress. To accelerate degradation of insulation, induction motor in service condition was subjected by a lot of pressure simultaneously, including thermal, moisture, and salt contamination. The accelerated aging testing was gradually conducted according to three schemes with different pressure levels. The results showed that the applied stresses could accelerate the insulation aging. A significant decrease of IR and PI values was found in the third scheme, as the IR value was less than 5 MΩ and the PI value was 0.6 (danger category). The insulation failure was achieved at a total duration of testing for 222 hours. The results of SEM-EDX and XRD testing showed the presence of mineral deposits from water vapor, salt contaminants, cracks, and fracture on the insulation surface. Intisari-Pengoperasian motor induksi yang dipengaruhi oleh faktor tekanan dapat menyebabkan degradasi isolasi. Degradasi tersebut dapat diamati dari perubahan karakteristik isolasi, meliputi elektris, fisik, dan kimiawi. Makalah ini bertujuan untuk mengevaluasi nilai tahanan isolasi dan indeks polarisasi sejak kondisi motor induksi baik hingga rusak. Pengujian SEM-EDX juga dilakukan untuk menganalisis perubahan mikrostruktur, karakteristik morfologi, dan komposisi kimia pada isolasi belitan motor. Di samping itu, pengujian XRD dilakukan untuk memvalidasi bahwa kerusakan isolasi disebabkan oleh tekanan yang diberikan. Untuk mempercepat degradasi isolasi, motor induksi dalam kondisi beroperasi diberikan banyak tekanan secara simultan, meliputi termal (karena beban lebih), kelembapan, dan kontaminasi garam (sebagai partikel konduktif). Pengujian dilakukan secara bertahap menurut tiga skema dengan tingkat tekanan yang berbeda-beda. Hasil menunjukkan bahwa pemberian tekanan secara simultan mampu mempercepat umur isolasi. Penurunan nilai IR dan PI yang signifikan ditemui pada pengujian skema 3, sebagaimana nilai IR kurang dari 5 MΩ dan nilai PI sebesar 0,6 (kategori berbahaya). Kegagalan isolasi tercapai pada total durasi pengujian selama 222 jam. Hasil pengujian SEM-EDX dan XRD menunjukkan adanya endapan mineral dari uap air, kontaminan garam, retakan, dan patahan pada permukaan isolasi. Kata Kunci-Indeks polarisasi (PI), degradasi isolasi motor, SEM-EDX, tahanan isolasi (IR), XRD.
