Results 181 to 190 of about 1,951 (227)

Ageing of metal oxide varistors due to surges

2011 International Symposium on Lightning Protection, 2011
Surge arresters are exposed to a series of stresses that trigger changes in their nonlinear behaviors. This paper deals with the ageing of metal oxide varistors concerning the stresses associated to high current short duration surges. The ageing of the samples is evaluated by analyzing the evolution of the resistive component of the leakage current ...
Credson de Salles, Manuel L. B. Martinez, Alvaro Antonio Alencar de Queiroz   +2 more
openaire   +1 more source

Long-time polarization currents in metal-oxide varistors

Journal of Applied Physics, 1976
The low-frequency (100–10−4 Hz) behavior of metal-oxide varistors is obtained from analysis of the charging and discharging currents which flow upon the application and removal of a step voltage. These results are compared to data for the complex dielectric constant ε=ε′−iε″ obtained using an ac bridge in the frequency range 101–10−1 Hz.
H. R. Philipp, Lionel M. Levinson
openaire   +1 more source

Metal oxide varistors as surge suppressors

1995 International Conference on Electromagnetic Interference and Compatibility (INCEMIC), 2002
High voltage transients and surges are produced due to lightning, inductive load switching, and spikes or electrical noise on power lines. These voltage surges can be as high as 6 kV and the transient period can vary from a few microseconds to milliseconds. The frequencies of these surges vary randomly depending upon the source voltage.
openaire   +1 more source

A ZnO varistor derived from metal oxide diffusion

Journal of Physics D: Applied Physics, 1989
Non-ohmic characteristics of ZnO varistors are obtained by diffusing Bi2O3 and/or Sb2O3 into a ZnO-based matrix. The varistors derived from metal oxide diffusion have a smaller non-linearity parameter, lower threshold field, larger dielectric constant and larger dissipation factor than conventionally processed varistors.
Bi-Shiou Chiou, Tzuu-Chian Chen, Jenq-Gong Duh   +2 more
openaire   +1 more source

Metal oxide varistor-A multijunction thin-film device

Applied Physics Letters, 1974
The physical origin of the highly nonlinear current-voltage relation in metal oxide varistors is shown to be consistent with Fowler-Nordheim tunneling.
Lionel M. Levinson, H. R. Philipp
openaire   +1 more source

Tunneling of photoexcited carriers in metal oxide varistors

Journal of Applied Physics, 1975
ZnO-based ceramic varistors exhibit photocurrents which vary in a highly nonlinear manner with applied voltage. It follows that varistor behavior is controlled by electrical barriers at the ZnO-grain–intergranular-layer interface.
H. R. Philipp, Lionel M. Levinson
openaire   +1 more source

Barrier voltage measurement in metal oxide varistors

Journal of Applied Physics, 1976
A combination of electrical and ceramic microstructural data has been used to determine the voltage drop across the ZnO-intergranular barrier in some simple and multicomponent ZnO-based varistors at the onset of high non-Ohmicity. The data are obtained by measuring the varistor breakdown field (V/mm) and average grain size of the conductive ZnO matrix ...
openaire   +1 more source

Low-temperature ac properties of metal-oxide varistors

Journal of Applied Physics, 1978
Low-temperature (3.5<T<77 °K) measurements of the dielectric constant and dissipation of ZnO ceramic varistors are presented for frequencies f in the range 30<f<105 Hz. A loss peak and dispersion in ε observed at 4 °K are identified as resulting from the two-phase structure of the ZnO varistor (Maxwell-Wagner model). We find
Lionel M. Levinson, H. R. Philipp
openaire   +1 more source

Nano-Enabled Metal Oxide Varistors for Surge Protection

2008 IEEE International Power Modulators and High-Voltage Conference, 2008
Commercial metal oxide varistor (MOV) devices provide a combination of high voltage, peak current, pulse energy absorption, and fast response speed. The non-uniformity and defects, however, may lead to relatively low voltage and energy dissipation, high leakage, low reliability and mechanical cracking.
Daniel Tan, Karim Younsi, Yingneng Zhou, Yang Cao, Patricia Irwin   +4 more
openaire   +1 more source

Testing Metal–Oxide Varistors for HVDC Breaker Application

IEEE Transactions on Power Delivery, 2019
There is growing interest in changing the power grid infrastructure. It is increasingly important to transport a large amount of renewable energy over long distances. To minimize losses, meshed dc-grids are needed but require the development of dc circuit breakers. Without it, a meshed grid cannot be operated. Actually different concepts of dc breakers
Maike Broker, Volker Hinrichsen
openaire   +1 more source