Calabrese Elisa, Raimondo Marialuigia, Catauro Michelina, Vertuccio Luigi, Lamberti Patrizia, Raimo Raffaele, Tucci Vincenzo, Guadagno Liberata
Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
Department of Engineering, University of Campania "Luigi Vanvitelli", Via Roma 29, 81031 Aversa, Italy.
Polymers (Basel). 2023 Mar 9;15(6):1374. doi: 10.3390/polym15061374.
This paper undertakes the thermal and electrical characterization of three commercial unsaturated polyester imide resins (UPIR) to identify which among them could better perform the insulation function of electric motors (high-power induction motors fed by pulse-wide modulation (PWM) inverters). The process foreseen for the motor insulation using these resins is Vacuum Pressure Impregnation (VPI). The resin formulations were specially selected because they are one-component systems; hence, before the VPI process, they do not require mixing steps with external hardeners to activate the curing process. Furthermore, they are characterized by low viscosity and a thermal class higher than 180 °C and are Volatile Organic Compound (VOC)-free. Thermal investigations using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) techniques prove their excellent thermal resistance up to 320 °C. Moreover, impedance spectroscopy in the frequency range of 100 Hz-1 MHz was analyzed to compare the electromagnetic performance of the considered formulations. They manifest an electrical conductivity starting from 10 S/m, a relative permittivity around 3, and a loss tangent value lower than 0.02, which appears almost stable in the analyzed frequency range. These values confirm their usefulness as impregnating resins in secondary insulation material applications.
本文对三种商用不饱和聚酯酰亚胺树脂（UPIR）进行了热性能和电性能表征，以确定它们中哪一种在电动机（由脉宽调制（PWM）逆变器供电的大功率感应电动机）的绝缘功能方面表现更佳。使用这些树脂进行电机绝缘的预想工艺是真空压力浸渍（VPI）。之所以特别选择这些树脂配方，是因为它们是单组分体系；因此，在VPI工艺之前，它们不需要与外部固化剂混合步骤来启动固化过程。此外，它们的特点是低粘度、热等级高于180°C且无挥发性有机化合物（VOC）。使用热重分析（TGA）和差示扫描量热法（DSC）技术进行的热研究证明了它们在高达320°C时具有优异的热阻。此外，还分析了100 Hz - 1 MHz频率范围内的阻抗谱，以比较所考虑配方的电磁性能。它们的电导率从10 S/m开始，相对介电常数约为3，损耗角正切值低于0.02，在分析的频率范围内几乎保持稳定。这些值证实了它们作为浸渍树脂在二次绝缘材料应用中的实用性。
