Diamond enriched lamination and winding insulation for electrical machines

2019 ◽  
Vol 38 (4) ◽  
pp. 1245-1252
Author(s):  
Aron Szucs ◽  
Zlatko Kolondzovski ◽  
Jan Westerlund ◽  
Juha Vahala
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
System Analysis ◽  
Electrical Machines ◽  
Production Costs ◽  
Electrical Machine ◽  
Paradigm Change ◽  
Electrical Insulator ◽  
Content Type ◽  
Winding Insulation

Purpose The thermal management of electrical insulations poses a challenge in electrical devices as electrical insulators are also thermal insulators. Diamond is the best solid electrical insulator and thermal conductor. This can lead to a paradigm change for electrical machine winding and lamination insulation design and thermal management. The paper introduces these techniques and discusses its effect for the design of electrical machines and its potential consequences for electromagnetic analysis, for example, in multi-physics modelling. The diamond winding insulation is patent-pending, but the diamond enriched lamination insulation is published for the benefit of the scientific community. Design/methodology/approach The windings of electrical machines are insulated to avoid contact between the coil and other conductive components, for example, the stator core. The principle of using mica tape and resin impregnation has not changed for a century and is well established to produce main insulation on a complex conductor shape and size. These insulations have poor heat-conducting properties. Similarly, the insulation of laminated steel sheets comprising the stator and rotor restrict heat flow. Diamond-based insulation provides a new path. Increased thermal conductivity means reduced temperature rise and the reduced thermal time constants in multi-physics simulations and system analysis. Findings The largest benefit of a diamond-based core insulation is in electrical machines in which the losses are conducted axially to the coolant. These are machines with radial ducts and effective cooling in the end regions. The main benefit will be in reducing the number of radial ducts that positively affect the size, production costs and the copper losses of the machine. The increased thermal conductivity of the diamond insulation system will reduce the thermal constants noticeably. These will affect system behavior and the corresponding simulation methods. Originality/value Diamond insulation can lead to a paradigm change for electrical machine winding and lamination insulation design and thermal management. It might also lead to new modeling requirements in system analysis.

Towards design of electrical machines from given air gap field

2017 ◽  
Vol 36 (1) ◽  
pp. 332-349
Author(s):  
Arto Poutala ◽  
Saku Suuriniemi ◽  
Timo Tarhasaari ◽  
Lauri Kettunen
Keyword(s):  
Cauchy Problem ◽  
Solution Process ◽  
Cauchy Data ◽  
Air Gap ◽  
Electrical Machines ◽  
Work Flow ◽  
Electrical Machine ◽  
Design Work ◽  
Content Type ◽  
Standard Design

Purpose The purpose of this paper is to introduce a reverted way to design electrical machines. The authors present a work flow that systematically yields electrical machine geometries from given air gap fields. Design/methodology/approach The solution process exploits the inverse Cauchy problem. The desired air gap field is inserted to this as the Cauchy data, and the solution process is stabilized with the aid of linear algebra. Findings The results are verified by solving backwards the air gap fields in the standard way. They match well with the air gap fields inserted as an input to the system. Originality/value The paper reverts the standard design work flow of electrical motor by solving directly for a geometry that yields the desired air gap field. In addition, a stabilization strategy for the underlying Cauchy problem is introduced.

scholarly journals Thermally Induced Mechanical Stress in the Stator Windings of Electrical Machines

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2113 ◽  
Author(s):  
Bishal Silwal ◽  
Peter Sergeant
Keyword(s):  
Mechanical Stress ◽  
Temperature Cycling ◽  
Electrical Machines ◽  
Electrical Machine ◽  
Thermally Induced ◽  
Stator Windings ◽  
Mechanical Models ◽  
Set Up ◽  
Winding Insulation ◽  
Main Factor

The lifetime of an electrical machine mainly depends on the thermal overloading. Modern day applications of electrical machines on one hand require compact machines with high power density, while on the other hand force electrical machines to undergo frequent temperature cycling. Until recently, in the case of electrical machines, the main factor related to the degradation of the winding insulation was thought to be the thermal oxidization of the insulation materials. It has now been revealed that thermal overloading can also induce mechanical stress in the windings of electrical machines, which over time could lead to fatigue and degradation. In this paper, a comprehensive study of the thermally induced mechanical stress in the windings of an electrical machine is presented. The study is performed using combined thermo-mechanical models. The numerical results are validated by experiments on a segmented stator winding set-up.

scholarly journals Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4144
Author(s):  
Yatai Ji ◽  
Paolo Giangrande ◽  
Vincenzo Madonna ◽  
Weiduo Zhao ◽  
Michael Galea
Keyword(s):  
Power Density ◽  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Electrical Machines ◽  
Design Stage ◽  
Switching Frequency ◽  
Special Focus ◽  
Electrical Machine ◽  
Engineering Approach

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

Evaluation of compression-recovery and thermal characteristics of multilayer bedding textiles

2020 ◽  
Vol 32 (5) ◽  
pp. 631-643
Author(s):  
Sedat Özer ◽  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Thermal Conductivity ◽  
Sleep Quality ◽  
Thermal Comfort ◽  
Sleep Duration ◽  
Human Body ◽  
Design Methodology ◽  
Thermal Characteristics ◽  
Air Permeability ◽  
Content Type ◽  
Thermal Comfort Properties

PurposeDesign of bedding textiles that contact the human body affects the sleep quality. Bedding textiles contribute to comfort sense during the sleep duration, in addition to ambient and bed microclimate. The purpose of this study is to evaluate the effects of different layer properties on the compression recovery and thermal characteristics of multilayer bedding textiles.Design/methodology/approachIn this study, woven and knitted multilayer bedding textiles were manufactured from fabric, fiber, sponge and interlining, respectively. Different sponge thickness, fiber and interlining weight were used in the layers of samples. Later, the pilling resistance, compression and recovery, air permeability and thermal conductivity of multilayer bedding textiles were investigated.FindingsThe results indicated that samples with the higher layer weight and thickness provide better compression recovery and lower air permeability properties. It was also found that knitted surfaces show the higher air permeability than the woven surfaces depending on the fabric porosity. Layer properties have insignificant effect on the thermal conductivity values.Originality/valueWhile researchers mostly focus on thermal comfort properties of garments, there are limited studies about comfort properties of bedding textiles in the literature. Furthermore, compression recovery properties of bedding textiles have also a great importance in terms of comfort. Originality of this study is that these properties were analyzed together.

scholarly journals Ceramic-like Composite Systems for Winding Insulation of Electrical Machines

2020 ◽  
Author(s):  
Soren Miersch ◽  
Ralph Schubert ◽  
Thomas Schuhmann ◽  
Uwe Schuffenhauer ◽  
Markus Buddenbohm ◽  
...  
Keyword(s):  
Electrical Machines ◽  
Composite Systems ◽  
Winding Insulation

scholarly journals Study of the Turning Nickel Base Alloy Pyromet® 31V (SAE HEV8)

2011 ◽  
Vol 278 ◽  
pp. 312-320 ◽  
Author(s):  
Marcos Valério Ribeiro ◽  
André Luís Habib Bahia
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Strength ◽  
High Temperatures ◽  
Base Alloy ◽  
Production Costs ◽  
Machining Parameters ◽  
Nickel Base Alloy ◽  
Low Thermal Conductivity ◽  
Nickel Base ◽  
Coated Carbide

Considering the constant technological developments in the aeronautical, space, automotive, shipbuilding, nuclear and petrochemical fields, among others, the use of materials with high strength mechanical capabilities at high temperatures has been increasingly used. Among the materials that meet the mechanical strength and corrosion properties at temperatures around 815 °C one can find the nickel base alloy Pyromet® 31V (SAE HEV8). This alloy is commonly applied in the manufacturing of high power diesel engines exhaust valves where it is required high resistance to sulphide, corrosion and good resistance to creep. However, due to its high mechanical strength and low thermal conductivity its machinability is made difficult, creating major challenges in the analysis of the best combinations among machining parameters and cutting tools to be used. Its low thermal conductivity results in a concentration of heat at high temperatures in the interfaces of workpiece-tool and tool-chip, consequently accelerating the tools wearing and increasing production costs. This work aimed to study the machinability, using the carbide coated and uncoated tools, of the hot-rolled Pyromet® 31V alloy with hardness between 41.5 and 42.5 HRC. The nickel base alloy used consists essentially of the following components: 56.5% Ni, 22.5% Cr, 2,2% Ti, 0,04% C, 1,2% Al, 0.85% Nb and the rest of iron. Through the turning of this alloy we able to analyze the working mechanisms of wear on tools and evaluate the roughness provided on the cutting parameters used. The tests were performed on a CNC lathe machine using the coated carbide tool TNMG 160408-23 Class 1005 (ISO S15) and uncoated tools TNMG 160408-23 Class H13A (ISO S15). Cutting fluid was used so abundantly and cutting speeds were fixed in 75 and 90 m/min. to feed rates that ranged from 0.12, 0.15, 0.18 and 0.21 mm/rev. and cutting depth of 0.8mm. The results of the comparison between uncoated tools and coated ones presented a machined length of just 30% to the first in relation to the performance of the second. The coated tools has obtained its best result for both 75 and 90 m/min. with feed rate of 0.15 mm/rev. unlike the uncoated tool which obtained its better results to 0.12 mm/rev.

scholarly journals The Impact of Thermal Degradation on Properties of Electrical Machine Winding Insulation Material

2016 ◽  
Vol 52 (4) ◽  
pp. 2951-2960 ◽  
Author(s):  
Malgorzata Sumislawska ◽  
Konstantinos N. Gyftakis ◽  
Darren F. Kavanagh ◽  
Malcolm D. McCulloch ◽  
Keith J. Burnham ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Electrical Machine ◽  
Insulation Material ◽  
Winding Insulation ◽  
The Impact
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