Journal ArticleDOI
Failure mechanism of winding insulations in inverter-fed motors
TLDR
In this article, the failure of magnet wires under repetitive pulses is attributed to a single factor but is a result of the combined effects of partial discharge, dielectric heating, and space charge formation.Abstract:
The failure of magnet wires under repetitive pulses as seen in inverter-fed motors cannot be attributed to a single factor but is a result of the combined effects of partial discharge, dielectric heating, and space charge formation. Voltage overshoots produced by PWM drives may be above discharge inception voltage. Partial discharge may therefore be present in inverter-fed motors. In addition to partial discharge, pulses with a fast rise time and high frequency enable the insulation to generate local dielectric heating, which increases the local temperature. The degradation rate of the insulation is therefore increased. Furthermore, the fast rise and fall of pulses make it possible for space charges to accumulate in the winding insulation and on its surface.read more
Citations
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Journal ArticleDOI
Relation between space charge accumulation and partial discharge activity in enameled wires under PWM-like voltage waveforms
TL;DR: In this article, the relation between partial discharge quantities (e.g., inception voltage, repetition frequency, amplitude) and electrical properties, associated with charge accumulation, which can be directly evaluated through space charge measurements.
Journal ArticleDOI
Bringing an insulation to failure: the role of space charge
TL;DR: The goal is to show how much space charge can contribute directly or indirectly, through local electric field magnification or alteration, to increase ageing rate or even trigger more energetic, thus faster, degradation processes in insulation design and electrical apparatus long-term performance/reliability.
Journal ArticleDOI
Progress in electrothermal life modeling of electrical insulation during the last decades
TL;DR: In this article, the authors highlight the achievements during the last decades in life modeling under electrothermal stress, considering both Phenomenological and physical models, considering also a statistical approach, with applications to experimental results.
Journal ArticleDOI
Progress in and prospects for electrical insulating materials
Shengtao Li,Shihu Yu,Yang Feng +2 more
TL;DR: The performance of electrical equipment and devices is determined to a great extent by the properties of their insulating materials as mentioned in this paper, such as electrical breakdown strength, thermal conductivity, temperature resistance, corona resistance, and specific energy storage in dielectrics.
Journal ArticleDOI
Effect of rise time on PD pulse features under repetitive square wave voltages
TL;DR: In this article, the influence of repetitive square wave voltage rise time on partial discharge pulse characteristics in the ultra-high frequency range was investigated using single-point contact crossed pairs with a wide range of rise times, from 200 ns to 400 μs.
References
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Proceedings ArticleDOI
Analysis of the impact of pulse-width modulated inverter voltage waveforms on AC induction motors
TL;DR: In this article, the effects of the voltage waveform on the performance of a PWM adjustable speed drive on an AC motor were investigated. But the authors did not reveal any new technology or major breakthrough pertaining to the impact of pulse-width modulated (PWM) adjustable speed drives operating on AC motors.
Proceedings ArticleDOI
Failure mechanism of the interturn insulation of low voltage electric machines fed by pulse controlled inverters
TL;DR: In this paper, the authors investigated the relationship between the PD inception voltage and velocity of the resulting electrical ageing, depending on the voltage characteristics, insulation design and temperature of the interturn insulation.
Journal ArticleDOI
Implications for the application of adjustable speed drive electronics to motor stator winding insulation
J.A. Oliver,G.C. Stone +1 more
TL;DR: In this paper, it is shown that the surges created by ASDs will not pose a threat to properly designed and manufactured insulation, however, as ASDs become more popular in the higher voltage ranges, we will have to watch carefully to ensure that insulation problems do not increase.
Journal ArticleDOI
Investigation of the effect of repetitive voltage surges on epoxy insulation
TL;DR: In this paper, the aging of epoxy electrical insulation by unipolar, repetitive voltage surges has been investigated to determine whether such surges can precipitate premature failure of high-voltage motor windings and gas insulated switchgear spacers.
Proceedings ArticleDOI
Improved magnet wire for inverter-fed motors
TL;DR: The inverter pulse resistant magnet wire, Thermaleze Q', was developed and introduced to the market in September 1995 and has been proved to be a greatly improved product for inverter-fed motor applications.