The selection of the frequency range for high-voltage on-site testing of extruded insulation cable systems

2000 ◽  
Vol 16 (6) ◽  
pp. 11-16 ◽  
Author(s):  
E. Gockenbach ◽  
W. Hauschild
Keyword(s):  
High Voltage ◽  
Frequency Range ◽  
Site Testing ◽  
Cable Systems ◽  
Selection Of

Selection of Component Modes for Craig-Bampton Substructure Representations

1996 ◽  
Vol 118 (2) ◽  
pp. 264-270 ◽  
Author(s):  
D. C. Kammer ◽  
M. J. Triller
Keyword(s):  
Efficient Method ◽  
Singular Values ◽  
General Purpose ◽  
Mode Shapes ◽  
Frequency Range ◽  
Reduced Representation ◽  
Absolute Measure ◽  
Fixed Interface ◽  
Interface Mode ◽  
Selection Of

Three measures of modal dynamic importance are studied for the purpose of ranking Craig-Bampton substructure fixed interface mode shapes based upon their contribution to forces at the substructure interface, modal velocity, or modal displacement. These measures can be employed to identify mode shapes which are dynamically important and thus should be retained in a reduced analytical representation, or identified during a modal survey of the substructure. The first method considered. Effective Interface Mass, has been studied previously. However, new results are presented showing the relation between Effective Interface Mass and a commonly used control dynamics measure of modal importance called approximate balanced singular values. In contrast to the general case of approximate balanced singular values, Effective Interface Mass always gives an absolute measure of the dynamic importance of mode shapes. The EIM method is extended to consider modal velocity and modal displacement outputs. All three measures are applied to a simple substructure called the General Purpose Spacecraft. It is shown that each of these measures provides an efficient method for ranking the dynamic importance of Craig-Bampton fixed interface modes such that a reduced representation will accurately reproduce the substructure’s response in the frequency range of interest.

High-voltage synthetic inductor for vibration damping in resonant piezoelectric shunt

2020 ◽  
pp. 107754632095261
Author(s):  
Kevin Dekemele ◽  
Patrick Van Torre ◽  
Mia Loccufier
Keyword(s):  
Piezoelectric Material ◽  
High Voltage ◽  
State Of The Art ◽  
Vibration Damping ◽  
Operational Amplifiers ◽  
Frequency Range ◽  
Resonant Condition ◽  
Passive Components ◽  
Resonance Frequencies ◽  
Resonant Shunt

Resonant piezoelectric shunts are a well-established way to reduce vibrations of mechanical systems suffering from resonant condition. The vibration energy is transferred to the electrical domain through the bonded piezoelectric material where it is dissipated in the shunt. Typically, electrical and mechanical resonance frequencies are several orders apart. As such, finding a suitable high inductance component for the resonant shunt is not feasible. Therefore, these high inductance values are mimicked through synthetic impedances, consisting of operational amplifiers and passive components. A downside of these synthetic impedances is that standard operational amplifiers can only handle up to 30 V peak to peak and the state-of-the-art amplifiers up to 100 Vpp. However, as mechanical structures tend to become lighter and more flexible, the order induced voltages over the piezoelectric material electrode voltages increase above these limitations. In this research, a high-voltage synthetic inductor is proposed and built by combining the bridge amplifier configuration and the output voltage boost configuration around a single operational amplifier gyrator circuit, effectively quadrupling the range of the synthetic inductor to 400 Vpp. The impedance of the circuit over a frequency range is numerically and experimentally investigated. The synthetic inductor is then connected to a piezoelectric material bonded to a cantilever beam. Numerical and experimental investigation confirms the high-voltage operation of the implemented circuit and its suitability as a vibration damping circuit.

scholarly journals Pre-selection of the candidate fields for deep imaging of the epoch of reionization with SKA1-low

2020 ◽  
Vol 499 (3) ◽  
pp. 3434-3444
Author(s):  
Qian Zheng ◽  
Xiang-Ping Wu ◽  
Quan Guo ◽  
Melanie Johnston-Hollitt ◽  
Huanyuan Shan ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Low Frequency ◽  
Far Field ◽  
Frequency Range ◽  
High Quality ◽  
Average Surface ◽  
Square Kilometre Array ◽  
Broad Frequency Range ◽  
Deep Imaging ◽  
Selection Of

ABSTRACT The Square Kilometre Array (SKA) will be the first low-frequency instrument with the capability to directly image the structures of the epoch of reionization (EoR). Indeed, deep imaging of the EoR over five targeted fields of 20 sq deg each has been selected as the highest priority science objective for SKA1. Aiming at preparing for this highly challenging observation, we perform an extensive pre-selection of the ‘quietest’ and ‘cleanest’ candidate fields in the southern sky to be suited for deep imaging of the EoR using existing catalogues and observations over a broad frequency range. The candidate fields should meet a number of strict criteria to avoid contaminations from foreground structures and sources. The candidate fields should also exhibit both the lowest average surface brightness and smallest variance to ensure uniformity and high-quality deep imaging over the fields. Our selection eventually yields a sample of 7 ‘ideal’ fields of 20 sq deg in the southern sky that could be targeted for deep imaging of the EoR. Finally, these selected fields are convolved with the synthesized beam of SKA1-low stations to ensure that the effect of sidelobes from the far-field bright sources is also weak.

Impedance Determination for High Voltage Air-Core Reactor Over Wide Frequency Range Based on Impulse Injection Technique

2020 ◽  
Vol 35 (4) ◽  
pp. 1909-1917
Author(s):  
Yu-Hao Chen ◽  
Yan-Zhao Xie ◽  
Ke-Jie Li ◽  
Yi Zhou ◽  
Chong Gao ◽  
...  
Keyword(s):  
High Voltage ◽  
Wide Frequency Range ◽  
Injection Technique ◽  
Frequency Range ◽  
Air Core
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