Thermal Degradation Phenomena of Polymer Film on Magnet Wire for Electromagnetic Coils

Abstract

Polymer film insulation degradation is a major problem for electric machines which leads to short circuits, overheating and eventually the occurrence of catastrophic failure. Electrical insulation materials provide the vital function of turn-to-turn, phase to phase, and phase-to-ground electrical isolation for the electromagnetic coils and windings. This paper investigates the characterisation of early-onset degradation of thin-film magnet wire insulation at elevated temperatures from 200 to 275 • C. Sample specimens were analysed after ageing for 100 hours in terms of their physical properties [surface roughness, mass], chemical properties [Fourier Transform Infra-Red (FTIR) spectroscopy], dielectric properties [capacitance and dissipation factor] and electrical properties [voltage breakdown strength and resistance]. The results show that the specimen roughness and mass increase and decrease uniformly, respectively, with increased ageing temperature. Similar degradation results trends with respect to ageing temperature for the dielectric properties and electrical insulation strength is documented. The paper also reports an extended ageing study which investigates early breakdown voltage (EBV) on sample specimens over a much longer time duration, that of up to 1600 hours.

Evaluation of High-Frequency Current Ringing Measurements for Insulation Health Monitoring in Electrical Machines

“…In this section, the current ringing is obtained for different stator winding conditions, using the experimental setup described in Section III. The change of stator winding insulation with aging is studied in [23]- [26], where the focus was on the wire insulation. In [14], [17], [21], and [27], the whole stator winding was subjected to accelerated aging tests and a decrease of parasitic capacitances was observed.…”

Accelerated Aging Procedure and Online Method for Stator Insulation Monitoring of Induction Motors

“…Nevertheless, in many cases, accelerated aging is applied only to a specific part of the stator insulation. In [3], [18] and [19], the accelerated aging is applied only to the magnet wire that is used in the stator winding, whereas in [20]- [22] a twisted pair is aged. These tests evaluate the wire or the turn-to-turn insulations, but not the whole winding insulation.…”

Influence of Nanoparticles on the Dielectric Response of a Single Component Resin Based on Polyesterimide

“…Thus, the type of nanoparticles incorporated, not only the polymer matrix itself, also has an influence on the resulting dielectric properties of the investigated NCs. Research and development of new polymer nanocomposite materials creates new opportunities in nanotechnology suitable for industrial [ 19 ] and medical applications [ 20 ].…”