An investigation of the harmonic characteristics of transformer excitation current under nonsinusoidal supply voltage

1999 ◽  
Vol 14 (2) ◽  
pp. 450-458 ◽  
Author(s):  
A.H. Chowdhury ◽  
W.M. Grady ◽  
E.F. Fuchs
2019 ◽  
Vol 56 (2) ◽  
pp. 3-11
Author(s):  
L. Lavrinovicha ◽  
J. Dirba ◽  
K. Sejejs ◽  
E. Kamolins

Abstract The authors present a methodology for the calculation and optimisation of regulation laws that apply to electronically commutated synchronous motors with predefined characteristics. It is shown that the synchronous electronically commutated motors can provide predefined characteristics with the maintenance of high energy performance by simultaneously regulating supply voltage, excitation current and load angle.


2019 ◽  
pp. 82-87
Author(s):  
Nina P. Nestyorkina ◽  
Olga Yu. Kovalenko ◽  
Yulia A. Zhuravlyova

The article analyses the operational characteristics of 10W LED lamps with T8 bulb manufactured by ASD (Russia), Smartbuy (Taiwan), and VOLPE (PRC) and 18W FL with T8 bulb manufactured by PHILIPS (Poland) including the dependence of these lamps on the supply voltage. The results of measurements show that: a) the period of stabilisation of electric parameters and luminous flux of LED lamps does not cause discomfort of illumination unlike the said FL, the luminous flux of which at the moment of switching on is 70 % of the nominal value, which is reached after 13 minutes; b) with nominal voltage of supply network, the value of luminous flux of 10W ASD LED-T8R-STD LED lamp (Russia) is 6 % less than the declared one, and that of Smartbuy SBL-T8-10-64K-A (Taiwan) and VOLPE LED-T8-10W/DW/G13/FR/FIX/N (PRC) is even less; c) the general colour rendering index of all studied LED lamps is less than the declared one (72 instead of 80); d) the flicker index of all studied LED lamps does not exceed the declared value of 5 %; e) the characteristics of LED lamps almost do not depend on changes of the supply voltage within the range of ±10 %. The recommendations regarding the application of the studied LED lamps are given.


2020 ◽  
pp. 85-88 ◽  
Author(s):  
Nadezhda P. Kondratieva

The article describes the results of the study concerning the effect of the voltage level on current harmonic composition in greenhouses irradiators. It is found that its change affects the level of current harmonics of all types of the studied greenhouse irradiators. With decrease of nominal supply voltage by 10 %, the total harmonic distortion THDi decreases by 9 % for emitters equipped with high pressure sodium lamps (HPSL), by 10 % for emitters with electrode-less lamps and by 3 % for LED based emitters. With increase of nominal supply voltage by 10 %, THDi increases by 23 % for lighting devices equipped with HPSL, by 10 % for irradiators with electrode-less lamps and by 3 % for LED based emitters. Therefore, changes of supply voltage cause the least effect on the level of current harmonics of LED based emitters and then the emitters with electrode-less lamps. Change of the level of supply voltage causes the greatest effect on the level of current harmonics of HPSL based irradiators. Mathematical models of dependence of THDi on the level of supply voltage for greenhouse emitters equipped with LED, electrode-less lamps and HPSL lamps were formulated. These mathematical models may be used for calculations of total current when selecting transformers and supply cable lines for greenhouse lighting devices, for design of new or reconstruction of existing irradiation systems of greenhouse facilities, and for calculation of power losses in power supply networks of greenhouse facilities during feasibility studies for energy saving and energy efficiency increasing projects.


2011 ◽  
Vol E94-C (6) ◽  
pp. 1072-1075
Author(s):  
Tadashi YASUFUKU ◽  
Yasumi NAKAMURA ◽  
Zhe PIAO ◽  
Makoto TAKAMIYA ◽  
Takayasu SAKURAI

2013 ◽  
Vol E96.C (4) ◽  
pp. 538-545
Author(s):  
Takeshi OKUMOTO ◽  
Kumpei YOSHIKAWA ◽  
Makoto NAGATA

2016 ◽  
Vol E99.C (10) ◽  
pp. 1219-1225
Author(s):  
Masahiro ISHIDA ◽  
Toru NAKURA ◽  
Takashi KUSAKA ◽  
Satoshi KOMATSU ◽  
Kunihiro ASADA

2018 ◽  
Author(s):  
Tuba Kiyan ◽  
Heiko Lohrke ◽  
Christian Boit

Abstract This paper compares the three major semi-invasive optical approaches, Photon Emission (PE), Thermal Laser Stimulation (TLS) and Electro-Optical Frequency Mapping (EOFM) for contactless static random access memory (SRAM) content read-out on a commercial microcontroller. Advantages and disadvantages of these techniques are evaluated by applying those techniques on a 1 KB SRAM in an MSP430 microcontroller. It is demonstrated that successful read out depends strongly on the core voltage parameters for each technique. For PE, better SNR and shorter integration time are to be achieved by using the highest nominal core voltage. In TLS measurements, the core voltage needs to be externally applied via a current amplifier with a bias voltage slightly above nominal. EOFM can use nominal core voltages again; however, a modulation needs to be applied. The amplitude of the modulated supply voltage signal has a strong effect on the quality of the signal. Semi-invasive read out of the memory content is necessary in order to remotely understand the organization of memory, which finds applications in hardware and software security evaluation, reverse engineering, defect localization, failure analysis, chip testing and debugging.


Sign in / Sign up

Export Citation Format

Share Document