scholarly journals Electrical Modelling of Switching Arcs in a Low Voltage Relay at Low Currents

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6377
Author(s):  
Ammar Najam ◽  
Petrus Pieterse ◽  
Dirk Uhrlandt
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Low Voltage ◽  
Sudden Change ◽  
Linear Functions ◽  
Constant Current ◽  
Voltage Gradient ◽  
Arc Length ◽  
Arc Voltage ◽  
Intense Radiation

The arc behaviour of short, low current switching arcs is not well understood and lacks a reliable model. In this work, the behaviour of an arc in the air is studied during contact separation at low DC currents (0.5 A to 20 A) and for small gap lengths (0 mm to 6 mm). The experiments are performed on a low voltage relay with two different electrode configurations. The arc voltage is measured during the opening of the contacts at constant current. The arc length is determined optically by tracing the mean path of the arc over time from a series of high-speed images. From the synchronised data of voltage vs. distance, first a sudden jump of the voltage at the start of contact opening is observed. Secondly, a sudden change in the voltage gradient occurs as the arc is elongated. Short arcs with a length up to approximately 1.25 mm show an intense radiation in the overall gap region and high voltage gradients. An unexpected behaviour never reported before was observed for longer arcs at low current: Two characteristic regions occur, a region in front of the cathode, with a length of approximately 1.25 mm, having an intense radiation and a high voltage gradient as well as a region of much lower radiation intensity and a comparatively lower voltage gradient in the remaining gap area despite a small anode spot region. The characteristic border of approximately 1.25 mm is almost independent of the current. A generalised arc voltage model is proposed based on the assumption that a constant sheath voltage and two discrete field regions exist, which are modelled as two independent linear functions of voltage vs. length. The data for various currents is combined to yield a general non-linear function for predicting the arc voltage vs. arc length and current.

scholarly journals A Single-Chip High-Voltage Integrated Actuator for Biomedical Ultrasound Scanners

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5063 ◽  
Author(s):  
Hsia ◽  
Hsiao ◽  
Huang
Keyword(s):  
Power Consumption ◽  
High Voltage ◽  
High Speed ◽  
Low Voltage ◽  
Second Harmonic ◽  
Pulse Signal ◽  
Silicon On Insulator ◽  
Imaging Systems ◽  
Output Stage ◽  
Static Power

This article presents a high-voltage (HV) pulse driver based on silicon-on-insulator (SOI) technology for biomedical ultrasound actuators and multi-channel portable imaging systems specifically. The pulse driver, which receives an external low-voltage drive signal and produces high-voltage pulses with a balanced rising and falling edge, is designed by synthesizing high-speed, capacitor-coupled level-shifters with a high-voltage H-bridge output stage. In addition, an on-chip floating power supply has also been developed to simplify powering the entire system and reduce static power consumption. The electrical and acoustic performance of the integrated eight-channel pulse driver has been verified by using medical-grade ultrasound probes to acquire the transmit/echo signals. The driver can produce pulse signals >100 Vpp with rise and fall times within 18.6 and 18.5 ns, respectively. The static power required to support the overall system is less than 3.6 mW, and the power consumption of the system during excitation is less than 50 mW per channel. The second harmonic distortion of the output pulse signal is as low as −40 dBc, indicating that the integrated multi-channel pulse driver can be used in advanced portable ultrasonic imaging systems.

A Preliminary Study on CSAMT Anti-Jamming Transmitter System

2014 ◽  
Vol 962-965 ◽  
pp. 317-321
Author(s):  
Dang Li ◽  
Jun Lu Wang ◽  
Yong Li ◽  
Jian Hua Li ◽  
Pin Rong Lin
Keyword(s):  
Data Acquisition ◽  
High Voltage ◽  
High Speed ◽  
Low Voltage ◽  
Host Computer ◽  
Good Prospect ◽  
Interference Signal ◽  
Computer Data ◽  
Random Code ◽  
Data Acquisition Card

On the basis of the relevant identification theory of pseudo-random code signal, the signals of CSAMT are divided into three parts according to the frequency of the signal. The signals which are susceptible to 50Hz interference signal and its harmonic components should be set by pseudo-random code way. Others are set by single square waveform way. The Control and signal generation software of the transmitter system is built on the advanced virtual instrument platform, LabVIEW. The hardware of the transmitter system is mainly composed of host computer, data acquisition card, high-speed optocoupler, IGBT driver module and four IGBT switches. The data acquisition card generate PWM signals, the high-speed optocoupler isolates low-voltage part and high-voltage part. IGBT drive module and four IGBT switches constitute high-voltage part. Entire transmitter system is suitable for different environments and research tasks, the transmit frequency are adjustable, and the pseudo-random code signal has strong capability to suppress the interference signals. The control software on host computer is simple and clear. There is good prospect for the use.

scholarly journals Studies on Ejection of Cell Culture Medium by Electrohydrodynamic Method

2019 ◽  
Vol 78 ◽  
pp. 01007
Author(s):  
Zhang Haiyi ◽  
Wang Can ◽  
Wang Fei ◽  
Wang Yiwei ◽  
Wang Zhihai ◽  
...  
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Mononuclear Cells ◽  
Low Voltage ◽  
Human Peripheral Blood ◽  
Survival Rates ◽  
Voltage Source ◽  
High Speed Photography ◽  
Peripheral Blood Mononuclear ◽  
Electric Voltage

Sample deposition based on micro-droplet ejection has broad application prospects in the field of biomedicine. Ejection of RPMI-1640 medium (without and with cells) is investigated experimentally using a home-build electrohydrodynamic (EHD) ejection system, consisting of a liquid supplier and a nozzle, a high voltage source, a droplet collector, and a high speed photography module. Electric voltage is applied between the nozzle and the droplet collector. The liquid surface is charged and the ejection takes place when electric force overcomes the surface tension. The ejection process is studied by using high speed photography and image processing. At low voltage, a uniform ejection state is established with ejection frequency typically less than 50Hertz. At sufficiently high voltage, another uniform ejection state is reached with ejection frequency as high as 1300Hz. Human peripheral blood mononuclear cells, after ejection, show survival rates higher than 79%, manifesting EHD ejection as a promising technique for cell printing.

Design of a High-Voltage Signal Generator Applied Flashover Fault Detection

2015 ◽  
Vol 734 ◽  
pp. 930-934
Author(s):  
Jian Ye Liu ◽  
Jiao Ni
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Low Voltage ◽  
Pulse Method ◽  
Pulse Generation ◽  
Signal Generator ◽  
Simulation Research ◽  
Medium Voltage ◽  
Voltage Signal ◽  
Pressure Unit

For cable flashover failure, a signal generator design ideas of the NC DC high flash - DC medium voltage flash - low-voltage flash based on three pulse method, consists of three components: the DC source, medium-high pressure unit and low pressure unit. DC source adopts AC 220V power supply, after rectification, chopping booster output. The output of the DC source through an inverter and high-frequency boost get the high-voltage unit. Low unit through the high-speed switching devices and capacitor charging and discharging achieve nanosecond pulse generation. In this paper, the various aspects of the design of the system have made a detailed description and simulation research.

scholarly journals Experimental Studies of Arc Motion Between Two Parallel Runners with Splitter Plates

2020 ◽  
Vol 7 (1) ◽  
pp. 16-20
Author(s):  
J. Lu ◽  
J.-J. Gonzalez ◽  
P. Freton ◽  
M. Benmouffok ◽  
P. Fort ◽  
...  
Keyword(s):  
High Speed ◽  
Low Voltage ◽  
Voltage Drop ◽  
Circuit Breaker ◽  
Experimental Studies ◽  
Experimental Setup ◽  
High Speed Camera ◽  
Electrical Measurements ◽  
Arc Voltage ◽  
Splitter Plates

In this paper, we present an experimental study in a simplified arc chamber geometry of Low-Voltage Circuit Breaker (LVCB). The influence of vent aperture on arc motion and the influence of splitter plates on arc voltage drop and arc motion are studied. The arc chamber is composed by two parallel arc runners and following the configuration chosen by one or two splitter plates. The experimental setup is completed by a generator (capacitor bench with triggered switch), a high-speed camera and electrical measurements. The arc ignition, arc displacement, arc splitting and arc re-strike have been observed. The results will be described and discussed for different experimental configurations.

scholarly journals APPLICATION OF TASITRONS IN CIRCUITS WITH INDUCTIVE ENERGY STORAGE

2020 ◽  
Author(s):  
B. Volyar
Keyword(s):  
Energy Storage ◽  
High Voltage ◽  
High Speed ◽  
Low Voltage ◽  
Electron Flow ◽  
Current Source ◽  
Storage Capacitor ◽  
Storage Device ◽  
Generation Process ◽  
Inductive Energy Storage

Features of generating high voltage in a pulsed or weakly pulsating form for different applications with an inductive energy storage device are considered. High voltage (tens of kilovolts) is generated due to self-induction when the storage is disconnected using a high-voltage tacitron-type switch device from a low-voltage pumping current source (with voltage less than 1 kV). The tacitron is a gas-discharge triode with a dense control grid, which provides initiation of a discharge between the cathode and anode and pumping the storage at a positive voltage, and then disconnecting it from the pumping current source, when a negative voltage of 20-200 V is applied to the grid for the blocking of the electron flow to the anode. Tacitrons are able to turn-off currents from a few to hundreds of amperes in the presence of a high voltage between the cathode and anode that takes a time of the order of 1 μs. Diagrams of changes in time of the current and voltage of the tacitron and the load during the generation of both pulsed and weakly pulsating voltages are considered. In the latter case, an additional storage (filter) capacitor is connected in parallel with the load, supplying the load by energy during the pumping periods of the inductive storage, and a high-speed pulse gas-filled rectifier diode is proposed to use for the dynamic separation of the storage capacitor and tacitron circuits in the said periods. Formulas are given that allow one to evaluate the parameters of the high voltage generation process. It is proposed to use a combined switching device containing tacitron and pulse gas-filled diode in one envelope with a common cathode electrode to simplify the high voltage generator circuit.

Low-Voltage Variable Gain Current Amplifier for High-Voltage Signal Processing

2009 ◽  
Vol 129 (8) ◽  
pp. 1511-1517
Author(s):  
Nicodimus Retdian ◽  
Jieting Zhang ◽  
Takahide Sato ◽  
Shigetaka Takagi
Keyword(s):  
Signal Processing ◽  
High Voltage ◽  
Low Voltage ◽  
Current Amplifier ◽  
Variable Gain ◽  
Voltage Signal

Design Aspects of a High-Speed High-Voltage PMSM for Aerospace Application

2017 ◽  
Vol 10 (3) ◽  
pp. 122
Author(s):  
Flur Ismagilov ◽  
Nikita Uzhegov ◽  
Vyacheslav Vavilov ◽  
Denis Gusakov
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Aerospace Application
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