Lifetime Estimation of Enameled Wires Under Accelerated Thermal Aging Using Curve Fitting Methods

Abstract

Estimating the lifetime of enameled wires using the conventional/standard test method requires a significant amount of time that can endure up to thousands of testing hours, which could considerably delay the time-to-market of a new product. This paper presents a new approach that estimates the insulation lifetime of enameled wire, employed in electrical machines, using curve fitting models whose computation is rapid and accurate. Three curve fit models are adopted to predict the insulation resistance of double-coated enameled magnet wire samples, with respect to their aging time. The samples' mean time-to-failure is estimated, and performance of the models is apprised through a comparison against the conventional 'standard method' of lifetime estimation of the enameled wires. The best prediction accuracy is achieved by a logarithmic curve fit approach, which gives an error of 0.95% and 1.62% when its thermal index is compared with the conventional method and manufacturer claim respectively. The proposed approach provides a timesaving of 67% (83 days) when its computation time is compared with respect to the 'standard method' of lifetime estimation.INDEX TERMS Neural network, curve fitting, insulation lifetime, thermal aging, accelerated aging test, insulation resistance and dissipation factor.

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

“…A simple imitation of the winding insulation are wire pairs. Therefore, most publications deal with the study of the insulation issue on wire pairs [3], [44]- [46], [49], [68], [77], [79], [89]. In contrast, there are very few contributions dealing with flat wire/hairpin windings [90]- [94].…”

“…As a result, this aspect is not further discussed here. In summary, it can be stated that, despite a large number of publications, there is more dissent than consent about the influencing factors and their impact on measurable aging [43], [77], [119]- [121] tan(δ) ↑ [117], [121] IR ↓ [89], [119]- [122] electrical voltage type PDIV [2], [60], [68], [108], [112], [113], [123]-[125] ↔ [43], [76] polarity [35], [76], [108], [109] ↔…”

“…In the standard 60172 [133] the Arrhenius equation and linear regression are used. Besides the conventional curve fitting (( 18) -( 21)), in [89] a neural network was trained with the Bayesian regularization backpropagation (BRP) algorithm. Good results were obtained, so modern methods can also be applied.…”

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.…”

A Study on the Predictive Maintenance Algorithms Considering Load Characteristics of PMSMs to Drive EGR Blowers for Smart Ships

“…Thermal aging of the motor, due to these phase currents, is also a major cause of winding turn faults. The existing studies performed accelerated life evaluation using sample coils to predict the remaining life of motor windings [26][27][28]. They cannot predict the remaining life, depending on the load on the system.…”