Open AccessEvaluation of strand‐to‐strand capacitance and dissipation factor in thermally aged enamelled coils for low‐voltage electrical machines
Author(s) -
Madonna Vincenzo,
Giangrande Paolo,
Galea Michael
Publication year - 2019
Publication title -
iet science, measurement and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.418
H-Index - 49
eISSN - 1751-8830
pISSN - 1751-8822
DOI - 10.1049/iet-smt.2019.0071
Subject(s) - dissipation factor , materials science , capacitance , electromagnetic coil , electrical engineering , voltage , duty cycle , dissipation , reliability (semiconductor) , partial discharge , insulation system , dielectric , composite material , optoelectronics , engineering , physics , electrode , quantum mechanics , thermodynamics , power (physics)
The dissipation factor (i.e. tan δ ) and insulation capacitance (IC) measurements are conventional monitoring methods for assessing the aging level of insulation systems. These quantities provide an invaluable indication of the dielectric losses within the insulating materials. However, how these values are affected by the aging processes due to thermal stresses have until today never been investigated fully. Thus, this study exhibits the influence of thermal aging on tan δ and IC of windings for electrical machines (EMs). The work is performed for class 200, round enamelled magnet wire specimens. The study aims at improving the design process of EMs for short duty cycle applications; hence, its outcome might be included at the design stage for enhancing reliability and lifetime. Random wound coils are chosen in the performed study, because they are the most common winding arrangement for low‐voltage EMs, which are employed in a wide range of applications (e.g. from home appliances to aerospace motors). Based on the collected data, considerations regarding the impact of relative humidity on both the dissipation factor and IC are presented. Finally, the correlation between the partial discharge inception voltage and the diagnostic measurements is experimentally verified.