A review of thermal conductivity of epoxy composites filled with AlN or BN

Samek, Josef; Ondrůšek, Čestmír; Kurfurst, Jiri

doi:10.1109/eeeic.2017.7977576

Cited by 9 publications

(3 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2.5 W/(mꞏK) being achievable with high levels of filling [21] - [23]. In [24] - [27] the use of ceramic fillers is examined for high-voltage machines up to a filling level of 25 vol.-%, which doubles the thermal conductivity of the impregnating material from 0.3 W/(mꞏK) to 0.6 W/(mꞏK). As such, the excess temperature of the winding can be reduced by approx.…”

Section: B State Of Research -Ceramic-like Insulation Of Electrical M...mentioning

confidence: 99%

Development of Polymer-Ceramic Composite Materials for the Winding Insulation of Highly Utilized and Energy-Efficient Electrical Machines

Miersch,

Schubert,

Schuhmann

et al. 2023

IEEE Open J. Ind. Applicat.

View full text Add to dashboard Cite

The electromagnetic utilization of an electrical machine can be increased by raising the current density, with a limitation resulting from the maximum permissible temperature of the winding insulation. Conventional insulating materials only have a low specific thermal conductivity, which results in large temperature gradients in the winding cross-section and consequently hotspots. The article presents the development and characterization of ceramic-like composite materials based on filled polysiloxanes for the dip coating of lamination stacks and the impregnation of the winding of electrical machines. The specific equivalent thermal conductivity is determined on composite winding samples, the thermal cycle stability is examined and the microstructure is analyzed with the scanning electron microscope. The manufacturability and the partial discharge behavior are examined based on test samples. The results of tests on an electric traction machine are used to show the potential for increasing the power density.

show abstract

Section: B State Of Research -Ceramic-like Insulation Of Electrical M...mentioning

confidence: 99%

Development of Polymer-Ceramic Composite Materials for the Winding Insulation of Highly Utilized and Energy-Efficient Electrical Machines

Miersch,

Schubert,

Schuhmann

et al. 2023

IEEE Open J. Ind. Applicat.

View full text Add to dashboard Cite

show abstract

“…For instance, in [18] slot liners of different porosity are tested so that they can be partially impregnated with the more conductive resin. Other studies focus on the resin thermal properties: with the use of suitable additives the thermal conductivity can be increased [19] still preserving other important characteristics. The resin, in fact, must have low viscosity for a high impregnation rate, thermal expansion coefficient as close as possible to the windings and the stator, and high glass transition temperature for avoiding abrupt changes in thermal expansion coefficient while the motor is in operation.…”

Section: Sensitivity Analysismentioning

confidence: 99%

Thermal management of a Formula E electric motor: Analysis and optimization

Cavazzuti

Gaspari

Pasquale³

et al. 2019

Applied Thermal Engineering

View full text Add to dashboard Cite

show abstract

“…This improvement results in temperature reduction in stator winding. Thus, thermal conductivity and machine efficiency can be improved as well [91]. By using the insulation nanocomposites materials, improvements in the insulation lifetime, breakdown voltage, thermal conductivity are expected.…”

Section: Section V Polymer Nanocompositementioning

confidence: 99%

Survey of Insulation Systems in Electrical Machines

Hemmati

El-Refaie

2019

2019 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

View full text Add to dashboard Cite

Insulating materials and insulation systems design have been gaining more attentions as more electrical machines tend to operate in harsher environments for various applications. Harsh environments include high temperature, humidity, erosion, low air pressure, etc. This paper discusses recent advances in insulation systems for electrical machines. Insulation tests as well as test standards that have been used to evaluate insulation systems and detect insulation failures will be discussed. Insulating materials used for a wide range of industrial applications such as wind turbine generators, aerospace hybrid/electric powertrain, and hydro generators have been summarized. For the emerging high-altitude, highvoltage aerospace applications, partial discharge and its impact on insulation systems will be discussed. Finally, polymer nanocomposite materials with excellent thermal conductivity and dielectric strength are highlighted as an outlook. SECTION I. Introduction Due to the continued growth of renewable energys, the number of electrical machines used worldwide has significantly increased. Insulation system is a very critical component of electrical machines. Insulation breakdown can lead to failures, which eventually result unpredicted downtime and negative financial impacts and in some applications can be a safety hazard. For some specific industries where uninterruptible operation is required, the unpredicted downtime is unacceptable. The unpredicted downtime for an offshore oil plant would be $25,000/h [1]. The dielectric strength of electrical insulation materials has been gradually improved over the years. By introducing new materials in the past 20 years for instance, the dielectric strength of ground-wall insulation nearly doubled [2]. Electrical, mechanical, thermal, and ambient stresses can cause insulation degradation which consequently leads to insulation failure [3], [4]. Insulation failure causes short circuits in the stator winding and consequently high currents could pass through the defected stator winding [5]. A survey on 1141 induction motors with power ratings above 200 hp shows that around 30% of motor failures are due to insulation failures [6]. With advances in sensors, digital signal processing, diagnosis methods and test standards, insulation failures can be detected [7], [8]. Through online estimation of material degradation and lifetime in early stages, insulation systems of electric machines can be protected from further aging while unpredicted downtime could be avoided through scheduled maintenance. Even though insulation system is a passive component in an electrical machine which does not produce torque, insulation build/thickness (which represents the key thermal resistance in electrical machine)can have significant impact on the machine cooling and hence electrical loading and torque production. There have been several efforts to minimize insulation thickness for design compactness, low manufacturing cost and high efficiency [3]. The two main functions of insulation systems in electr...

show abstract

A review of thermal conductivity of epoxy composites filled with AlN or BN

Cited by 9 publications

References 31 publications

Development of Polymer-Ceramic Composite Materials for the Winding Insulation of Highly Utilized and Energy-Efficient Electrical Machines

Development of Polymer-Ceramic Composite Materials for the Winding Insulation of Highly Utilized and Energy-Efficient Electrical Machines

Thermal management of a Formula E electric motor: Analysis and optimization

Survey of Insulation Systems in Electrical Machines

Contact Info

Product

Resources

About