Maximum efficiency of an electromagnet with a linear magnetic system

1991 ◽  
Vol 27 (4) ◽  
pp. 333-336
Author(s):  
V. I. Malinin ◽  
A. N. Ryashenstev ◽  
A. I. Tolstik
1978 ◽  
Vol 39 (C6) ◽  
pp. C6-943-C6-945 ◽  
Author(s):  
H. Gudmundsson ◽  
H. U. Åström ◽  
D. New ◽  
K. V. Rao ◽  
H. S. Chen
Keyword(s):  

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-916-C6-917 ◽  
Author(s):  
B. H. Verbeek ◽  
G. J. Nieuwenhuys ◽  
H. Stocker ◽  
J. A. Mydosh

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1507-C8-1508 ◽  
Author(s):  
Y. Tazuke ◽  
T. Saitoh ◽  
F. Matsukura ◽  
T. Satoh ◽  
T. Miyadai ◽  
...  
Keyword(s):  

Author(s):  
A. M. Oleynikov ◽  
L. N. Kanov

The paper gives the description of the original wind electrical installation with mechanical reduction in which the output of vertical axis wind turbine with rather low rotation speed over multiplicator is distributed to a certain number of generators. The number of acting generators is determined by the output of actual operating wind stream at each moment. According to this constructive scheme, it is possible to provide effective and with maximum efficiency installation work in a wide range of wind speeds and under any schedule issued to the consumer of electricity. As there are no any experience in using such complexes, mathematical description of its main elements is given, namely windwheels, generators with electromagnetic excitation of magnetic electrical type, then their interaction with windwheel, and also the results of mathematical modeling of work system regimes under using the offered system of equations. The basis for the mathematical description of the main elements of the installation – synchronous generators – are the system of equations of electrical and mechanical equilibrium in relative units in rotating coordinates without considering saturation of the magnetic circuit. The equation of mechanical equilibrium systems includes torque and brake windwheel electromagnetic moments of generators with taking into account the reduction coefficients and friction. In addition, we specify the alternator rotor dynamics resulting from continuous torque of windwheel fluctuations under the influence of unsteady wind flow and wind speed serving as the original variable is modeled by a set of sinusoids. Model simplification is achieved by equivalization of similar generators and by disregarding these transitions with a small time constant. Calculation the installation with synchronous generators of two types of small and medium capacity taking into account the operational factors allowed us to demonstrate the logic of interactions in the main elements of the reported complex in the process of converting wind flow into the generated active and reactive power. We have shown the possibility of stable system work under changeable wind stream condition by regulating of the plant blade angle and with simultaneous varying of generator number of different types. All these are in great interest for project organizations and power producers.


Author(s):  
Nor Hayati Kassim ◽  
Norlina Mohamed Noor ◽  
Jati Kasuma ◽  
Juliza Saleh ◽  
Ceaser Dealwis ◽  
...  

Companies are now recognizing that their employees require a spectrum of mobile applications in order to achieve maximum efficiency at the workplace. Mobile applications such as WeChat, Twitter and WhatsApp via smartphones have become influential tools and extensively used by employees at the workplace. This state-of-the-art technology in communication has penetrated various fields, including routine administrative jobs at the workplace. The objective of this research is toinvestigate the acceptance of the WhatsApp mobile application for formal use among support staff at The Commission of the City of Kuching North, Sarawak (DBKU). Perceived usefulness, perceived ease of use and behavioral intention of the users in using WhatsApp are the variables measured for job performance. The researchers utilized convenience sampling, whereby a total of 105 employees from two departments participated in the investigation. Data was collected using a set of selfadministered questionnaires which was adapted from Davis. The findings revealed that perceived usefulness and perceived ease of use of WhatsApp as a means of communication were significant for job performance at DBKU. The employees felt more competent during their formal interaction at the workplace as less effort was needed while using WhatsApp. The existence of features which were user-friendly and easy operational functions helped to create positive attitudes when utilizing the application. Faster feedback, ease of use, and convenience were some of the reasons for the employees’ willingness to use WhatsApp for communication at the workplace.


Author(s):  
Igors Stroganovs ◽  
Andrejs Zviedris

Basic Statements of Research and Magnetic Field of Axial Excitation Inductor GeneratorIn this work the main features of axial excitation inductor generators are described. Mathematical simulation of a magnetic field is realized by using the finite element method. The objective of this work is to elucidate how single elements shape, geometric dimensions and magnetic saturation of magnetic system affect the main characteristics of the field (magnetic induction, magnetic flux linkage). The main directions of a magnetic system optimization are specified.


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