Results 171 to 180 of about 1,951 (227)
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Thermal Runaway in Metal Oxide Varistors
MRS Proceedings, 1981ABSTRACTThe conditions leading to thermal runaway in metal oxide varistors are discussed in terms of its power dissipation. An equivalent circuit is used to rationalize the similarities and differences between the DC and 60 Hz ac behavior.
Martin A. Seitz +2 more
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Surge ageing of metal oxide varistors
2015 IEEE Electrical Insulation Conference (EIC), 2015The objective of this paper is to analyze the ageing of metal oxide varistors (MOV) due to surges by the changes of the nonlinear behavior. The surge arrester installed in the field is submitted to the lightning stress superposed to the power frequency voltage, and so, submitted to an ageing process due to both cumulative stresses.
Credson de Salles +2 more
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Surface flashovers on metal-oxide varistor blocks
ICSD'98. Proceedings of the 1998 IEEE 6th International Conference on Conduction and Breakdown in Solid Dielectrics (Cat. No.98CH36132), 2002Extensive studies have been made of surface flashovers on varistor blocks using multipulse (MP) currents which simulate multiple stroke lightning ground flashes. The MP results are compared with those obtained with single-pulse (SP) currents and with high temporary overvoltages (TOV) at 50 Hz. The blocks used were mostly of 5 kA rating as commonly used
M. Darveniza, T.K. Saha
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Electrothermal and Overload Performance of Metal-Oxide Varistors
IEEE Transactions on Power Delivery, 2020The energy absorption capability of metal-oxide varistors, decidedly influenced by the electrothermal processes occurring within their microstructures, is a vital parameter for the effective surge protection. This paper proposes a numerical model for the simulation of the electrothermal phenomena occurring in metal-oxide varistors.
Zumret Topcagic +2 more
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Second-breakdown characteristics of metal-oxide varistors
Journal of Applied Physics, 1977Several new results on the electrical breakdown properties of ZnO-based ceramic varistors are presented. A second-breakdown phenomenon associated with thermal runaway and characterized by a negative differential conductivity was observed in dc tests. The curve of capacitance versus bias current exhibited hysteresis while the I-V characteristics became ...
J. J. Lee, J. K. O’Brien, M. S. Cooper
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Frequency limitation of metal-oxide varistors
International Journal of Electronics, 1992The frequency possibilities of metal-oxide varistors are investigated. An expression is deduced for the limiting frequency f o of their application. It is also expressed in terms of the catalogue data of commercial varistors or by means of the parameters or the ceramic material. An evaluation of the f o of ZnO, SnO2 and SrTiO3 varistors is made.
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Capacitance changes in degraded metal oxide varistors
Proceedings of the 2004 IEEE International Conference on Solid Dielectrics, 2004. ICSD 2004., 2004ZnO based ceramics show a highly nonlinear current-voltage (I-V) characteristic due to intergranular layers at the boundaries of ZnO grains. This research indicates that the junctions formed on the border between ZnO grains and the intergranular phase are responsible for the creation of potential barriers which control the flow of current through the ...
M. Jaroszewski +3 more
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Multi-factor ageing of metal oxide varistors
Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP'94), 2002Localised overheating of zinc oxide varistor elements due to the transfer of external leakage currents arising from the incidence of partial electrical discharges (PD) onto their outer surface has been shown to cause premature failure by surface breakdown.
N.M. Vong +3 more
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Repetitive Impulse Withstand Performance of Metal–Oxide Varistors
IEEE Transactions on Power Delivery, 2017This study focuses on the relationship between test current waveforms and impulse withstand capability of metal–oxide varistors (MOVs) (withstand energy, current density, and the number of withstand shots) in repetitive impulse application and discusses the mechanical and electrical failure mechanisms.
Naoyuki Tsukamoto, Masaru Ishii
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High Voltage Metal Oxide Varistors for Surge Protection
SAE Technical Paper Series, 2008<div class="htmlview paragraph">Zinc oxide based metal oxide varistors (MOV) are widely used electrical surge protection components. Modern high power, high-density electronics post more requirements such as smaller footprints, higher current density and higher nonlinearity on MOVs.
Daniel Qi Tan, Yang Cao, Baojin Chu
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