Scale Aspects of Electrical Machine Inductances

1995 ◽  
Vol 32 (2) ◽  
pp. 179-184
Author(s):  
H. C. J. De Jong
Keyword(s):  
Size Range ◽  
Electrical Machines ◽  
Electrical Machine ◽  
Wide Size Range

Scale aspects of electrical machine inductances Winding inductances have a natural trend to grow with increasing size. This may cause problems to electrical machines if, within a wide size range, the required per-unit values of certain reactances are more or less fixed. After having touched the transformer situation, two electrical machine solutions will be discussed: partial compartmentization of winding; interdependence of frequency and pole number.

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.

scholarly journals Effciency of an Electrical Machine in Electric Vehicle Application

2016 ◽  
Vol 11 (1) ◽  
pp. 20-29 ◽  
Author(s):  
S. B. Shah ◽  
B. Silwal ◽  
A. Lehikoinen
Keyword(s):  
Electric Vehicle ◽  
Standard Method ◽  
Operating Cost ◽  
Electrical Machines ◽  
Electrical Machine ◽  
Test Machine ◽  
Current Component ◽  
Element Analysis ◽  
Voltage Drops ◽  
Wide Range

Machines have always made life simpler, directly or indirectly. They have been developed for a very wide range of applications. For the per- formance analysis of any machine, one important parameter to be considered is the machine loss. This consideration has signifcances like determining the effciency of the machine which in turn infuences the operating cost, determining the heating of machine and for accounting the voltage drops or current component associated with the cause of the losses and many more. Losses in electrical machines can be categorized according to the causes or phenomena that produce them. The effciency of an electrical machine directly depends on different kind of losses in the machine. Therefore, in this paper we primarily focus on the losses in the machine. First, all possible losses, their causes and effects in an electrical machine have been explained. A brief account of calculating those losses has also been explained. The standard method of calculating the effciency follows after that. Finally, a fnite element analysis is performed for a test machine and the losses and the effciency of the test machine is stud- ied. Journal of the Institute of Engineering, 2015, 11(1): 20-29 

scholarly journals Modeling of Losses Due to Inter-Laminar Short-Circuit Currents in Lamination Stacks

2013 ◽  
Vol 3 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Sahas Bikram Shah ◽  
Paavo Rasilo ◽  
Anouar Belahcen ◽  
Antero Arkkio
Keyword(s):  
Boundary Layer ◽  
Short Circuit ◽  
Tangential Component ◽  
Electrical Machines ◽  
Electrical Machine ◽  
Induced Current ◽  
Layer Model ◽  
Boundary Layer Model ◽  
Fine Mesh ◽  
Additional Losses

Abstract The cores of electrical machines are generally punched and laminated to reduce the eddy current losses. These manufacturing processes such as punching and cutting deform the electrical sheets and deteriorate its magnetic properties. Burrs are formed due to plastic deformation of electrical sheets. Burr formed due to punching on the edges of laminated sheets impairs the insulation of adjacent sheet and make random galvanic contacts during the pressing of stacked sheets. The effect of circulating current occurs if the burrs occur on the opposite edges of the stacks of laminated sheets and incase of bolted or wielded sheets, induced current return through it. This induced current causes the additional losses in electrical machine. The existence of surface current on the boundary between two insulated regions causes discontinuity of tangential component of magnetic field. Hence, based on this principle, the boundary layer model was developed to study the additional losses due to galvanic contacts formed by burred edges. The boundary layer model was then coupled with 2-D finite element vector potential formulation and compared with fine mesh layer model. Fine mesh layer model consists of finely space discretized 950028 second order triangular elements. The losses were computed from two models and were obtained similar at 50 Hz. The developed boundary layer model can be further used in electrical machines to study additional losses due to galvanic contacts at the edges of stator cores.

The Mechanism of active capture of animal food by the Sergestid Shrimp Acetes Sibogae Australis

1998 ◽  
Vol 78 (2) ◽  
pp. 497-508 ◽  
Author(s):  
Lachlan Mcleay ◽  
C.G. Alexander
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Prey Capture ◽  
Size Range ◽  
The Third ◽  
Feeding Modes ◽  
In Captivity ◽  
Combined Actions ◽  
Wide Size Range ◽  
Scanning Electron

Combining the use of scanning electron microscopy and microcinematography with functional and behavioural observations has clarified many aspects underlying the feeding processes of the small planktonic sergestid shrimp Acetes sibogae australis. In captivity Acetes sibogae australis is an opportunistic feeder that uses four principal feeding modes to capture a wide size range of prey: Artemia nauplii (<0.33 mm), copepods (<1mm) and moribund Acetes (up to 25 mm). Prey capture is effected by combined actions of the first three pairs of pereiopods and the third maxillipeds before transfer to the more dorsal second maxillipeds. The second maxillipeds are the principal appendages used in securing, manipulating, sorting and rejecting prey before insertion into the vicinity of the inner mouthparts.

scholarly journals Conceptual Framework of Antecedents to Trends on Permanent Magnet Synchronous Generators for Wind Energy Conversion Systems

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2616 ◽  
Author(s):  
K. Padmanathan ◽  
N. Kamalakannan ◽  
P. Sanjeevikumar ◽  
F. Blaabjerg ◽  
J. B. Holm-Nielsen ◽  
...  
Keyword(s):  
Wind Energy ◽  
Energy Conversion ◽  
Conceptual Framework ◽  
Permanent Magnet ◽  
Electrical Machines ◽  
Special Focus ◽  
Electrical Machine ◽  
Synchronous Generators ◽  
Wind Energy Conversion ◽  
Permanent Magnet Synchronous Generators

Wind Energy Conversion System (WECS) plays an inevitable role across the world. WECS consist of many components and equipment’s such as turbines, hub assembly, yaw mechanism, electrical machines; power electronics based power conditioning units, protection devices, rotor, blades, main shaft, gear-box, mainframe, transmission systems and etc. These machinery and devices technologies have been developed on gradually and steadily. The electrical machine used to convert mechanical rotational energy into electrical energy is the core of any WECS. Many electrical machines (generator) has been used in WECS, among the generators the Permanent Magnet Synchronous Generators (PMSGs) have gained special focus, been connected with wind farms to become the most desirable due to its enhanced efficiency in power conversion from wind energy turbine. This article provides a review of literatures and highlights the updates, progresses, and revolutionary trends observed in WECS-based PMSGs. The study also compares the geared and direct-driven conversion systems. Further, the classifications of electrical machines that are utilized in WECS are also discussed. The literature review covers the analysis of design aspects by taking various topologies of PMSGs into consideration. In the final sections, the PMSGs are reviewed and compared for further investigations. This review article predominantly emphasizes the conceptual framework that shed insights on the research challenges present in conducting the proposed works such as analysis, suitability, design, and control of PMSGs for WECS.

The effect of oleic acid on the synthesis of Fe3−xO4 nanoparticles over a wide size range

2015 ◽  
Vol 17 (41) ◽  
pp. 27373-27379 ◽  
Author(s):  
Carlos Moya ◽  
Xavier Batlle ◽  
Amílcar Labarta
Keyword(s):  
Thermal Decomposition ◽  
Oleic Acid ◽  
Structural Properties ◽  
Acid Concentration ◽  
Size Range ◽  
Benzyl Ether ◽  
Oleic Acid Concentration ◽  
Wide Size Range

This work reports on the effect of the oleic acid concentration on the magnetic and structural properties of Fe3−xO4 nanoparticles synthesized by thermal decomposition of Fe(acac)3 in benzyl-ether.

Production, Characterization, and Deposition of Carbon Clusters

1990 ◽  
Vol 206 ◽  
Author(s):  
Y. K. Bae ◽  
D. C. Lorents ◽  
R. Malhotra ◽  
C. H. Becker ◽  
D. Tse ◽  
...  
Keyword(s):  
High Temperatures ◽  
Thermal Desorption ◽  
Size Range ◽  
Ion Source ◽  
Carbon Clusters ◽  
Heating Process ◽  
Cluster Ion Source ◽  
Semiconductor Clusters ◽  
Cluster Ion ◽  
Wide Size Range

ABSTRACTWe have developed a new cluster ion source that can generate intense beams of metal and semiconductor clusters of a very wide-size range. With the source, we have observed intense beams of carbon clusters with mean cluster sizes of up to 4000 atoms/clusters. However, we have found that for generating small fullerenes, such as C60 and C70, the recently discovered technique by Kraetschmer et al. is much more efficient. By improving the technique, we have generated gram quantities of C60 and C70 and systematically investigated their thermal desorption properties. During the heating process, we have discovered that at high temperatures the bulk fullerenes, fullerite, transformed to another form of carbon, which still evaporates at temperatures above 700 C, but does not dissolve in benzene.

Forming Load Calculation of Hot Precision Forging of Cylindrical Gears

2013 ◽  
Vol 456 ◽  
pp. 425-428
Author(s):  
Bin Zuo ◽  
Bao Yu Wang ◽  
Le Yi Yang
Keyword(s):  
Impact Factor ◽  
Size Range ◽  
Fe Simulation ◽  
Helical Gears ◽  
Forging Process ◽  
Cylindrical Gears ◽  
Forming Load ◽  
Precision Forging ◽  
Load Calculation ◽  
Wide Size Range

The Tooth Impact Factor was defined and introduced into the formula of forming load of closed-upsetting. Thus the formula for calculating the forming load of hot precision forging of cylindrical gears was put forward. The equation for the Tooth Impact Factor was fitted using the data from FE simulation of forging process in which gears with different modules were forged. Some forging tests for gears were conducted and the forming load was measured to ensure the validity of the formula. The tests also revealed that the formula is suitable for forming load calculation of hot precision forging of both spur and helical gears in a wide size range.

Experimental Observations on the Thermal Performance of a Rotating Coolant Circuit with Reference to the Design of Electrical Machine Rotors

1976 ◽  
Vol 190 (1) ◽  
pp. 561-570 ◽  
Author(s):  
W. D. Morris ◽  
F. M. Dias
Keyword(s):  
Energy Dissipation ◽  
Pressure Drop ◽  
Thermal Performance ◽  
Rotational Speed ◽  
Electrical Machines ◽  
Hydrodynamic Characteristics ◽  
Electrical Machine ◽  
Coolant Circuit

SYNOPSIS This paper presents the results of an investigation into the influence of rotation on the thermal and hydrodynamic characteristics of a rotating coolant circuit which has relevance to the design of cooled rotors for electrical machines. Tests conducted with a fixed pressure drop across the entire rotor circuit demonstrate that increases in rotational speed can produce consequential increases in the temperature of the simulated winding. This is true for the case where the energy dissipation is constant.

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