scholarly journals Numerical Analysis of low voltage Arc Motion Process at Various Frequencies

2017 ◽  
Vol 4 (1) ◽  
pp. 48-51
Author(s):  
J. Yin ◽  
X. Li ◽  
Q. Wang
Keyword(s):  
Low Voltage ◽  
Three Dimensional ◽  
Splitter Plate ◽  
Arc Plasma ◽  
Frequency Effects ◽  
Arc Voltage ◽  
Splitter Plates ◽  
Motion Time ◽  
Motion Process ◽  
Peak Increase

A three-dimensional (3D) magneto-hydro-dynamic (MHD) model of air arc plasma is built to investigate the frequency effects on the arc motion process with different number of splitter plates. Based on this model, the arc voltage and current density are obtained. The arc motion time is normalized with the frequency and compared at different numbers of splitter plate. The result shows that the normalized time and the arc voltage peak increase with increases of the number of splitter plate.

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 Analysis of Turn-to-Turn Fault on Split-Winding Transformer Using Coupled Field-Circuit Approach

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1314
Author(s):  
Cunxiang Yang ◽  
Yiwei Ding ◽  
Hongbo Qiu ◽  
Bin Xiong
Keyword(s):  
Low Voltage ◽  
Short Circuit ◽  
Three Dimensional ◽  
Great Influence ◽  
Normal Operation ◽  
Transient Field ◽  
Axial Forces ◽  
Leakage Field ◽  
Characteristics Analysis ◽  
Split Winding

The turn-to-turn faults (TTF) are also inevitable in split-winding transformers. The distorted leakage field generated by the TTF current results in large axial forces and end thrusts in the fault windings as well as affecting other branch windings normal operation, so it is of significance to study TTF of split-winding transformers. In this paper, the characteristics analysis of the split-winding transformer under the TTFs of the low voltage winding at different positions are presented. A 3600 KVA four split-windings transformer is taken as an example. Then, a simplified three-dimensional simplified model is established, taking into account the forces of the per-turn coil. The nonlinear-transient field-circuit coupled finite element method is used for the model. The leakage field distribution under the TTFs of the low voltage winding at different positions is studied. The resultant force of the short-circuit winding and the force of the per-turn coil are obtained. Subsequently, the force and current relationship between the branch windings are analyzed. The results show that the TTF at the specific location has a great influence on the axial windings on the same core, and the distorted leakage magnetic field will cause excessive axial force and end thrust of the normal and short-circuit windings. These results can provide a basis for the short-circuit design of split-winding transformer.

Fast Throughput Low Voltage Scanning Transmission Electron Microscope Imaging of Nano-Resolution Three Dimensional Tissue

2009 ◽  
Vol 15 (S2) ◽  
pp. 642-643
Author(s):  
M Bolorizadeh ◽  
HF Hess
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Low Voltage ◽  
Three Dimensional ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Microscope Imaging ◽  
Electron Microscope Imaging ◽  
Voltage Scanning

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Study on Fast-Convert Ultrasonic Frequency Pulse TIG Welding Arc Characteristic

2011 ◽  
Vol 704-705 ◽  
pp. 745-751 ◽  
Author(s):  
Bo Jin Qi ◽  
Ming Xuan Yang ◽  
Bao Qiang Cong ◽  
Wei Li
Keyword(s):  
Pulse Current ◽  
Current Level ◽  
Tig Welding ◽  
Ultrasonic Frequency ◽  
Arc Plasma ◽  
Arc Voltage ◽  
Welding Arc ◽  
Huge Impact ◽  
Pulse Peak ◽  
Frequency Pulse

Based on ultrasonic frequency pulse tungsten inert-gas (TIG) welding for 0Cr18Ni9Ti austenitic stainless steel, the influence of pulse level parameters was investigated on the field of arc characteristic and arc force. The experimental results show that the pulse level parameters could have huge impact to arc characteristic and arc force. With the increased frequency of pulse level, arc plasma has a more obvious pinch effect, which causes the enhance of arc voltage. Similarly, the arc force can be improved obviously compared with that during conventional direct current (DC) TIG welding. By contrast, the sensitivity of welding characteristic to pulse current level frequency would reduce while the duty of pulse peak current increased.

Simulation of the Effects of Several Factors on Arc Plasma Behavior in Low Voltage Circuit Breaker

2005 ◽  
Vol 7 (5) ◽  
pp. 3069-3072 ◽  
Author(s):  
Li Xingwen ◽  
Chen Degui ◽  
Wang Qian ◽  
Li Zhipeng
Keyword(s):  
Low Voltage ◽  
Circuit Breaker ◽  
Arc Plasma ◽  
Plasma Behavior

Hydrodynamic Forces on a Cylinder With a Flexible Splitter Plate Near the Free Surface

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
S. Satheesh ◽  
H. R. Díaz-Ojeda ◽  
L. M. González ◽  
F. J. Huera-Huarte
Keyword(s):  
Free Surface ◽  
Drag Reduction ◽  
Lift Force ◽  
Cross Flow ◽  
Hydrodynamic Forces ◽  
Splitter Plate ◽  
Rigid Cylinder ◽  
Splitter Plates ◽  
Cylinder Diameter

Abstract Experiments were conducted on two splitter plates of different structural rigidities, attached to a rigid cylinder and exposed to cross-flow at different submergence depths in order to study the influence of free surface. It was found that the presence of flexible splitter plate results in drag reduction at all submergence depths when compared with a plain cylinder, with the reduction being dependent on the rigidity of the splitter plate. The lift force was also found to increase abruptly at low depths for the cases involving splitter plates. The results from the analyses of tip kinematics on flexible splitter plate indicated that it performs vertical oscillations symmetrically about its mounting position at high submergence depths but is displaced in one direction up to an order of cylinder diameter and undergoes minimal oscillations when located near the free surface.

Flow instabilities in the wake of a circular cylinder with parallel dual splitter plates attached

2019 ◽  
Vol 874 ◽  
pp. 299-338 ◽  
Author(s):  
Rui Wang ◽  
Yan Bao ◽  
Dai Zhou ◽  
Hongbo Zhu ◽  
Huan Ping ◽  
...  
Keyword(s):  
Circular Cylinder ◽  
Rear Surface ◽  
Three Dimensional ◽  
Spectral Element ◽  
Cylinder Wake ◽  
Flow Topology ◽  
Weakly Nonlinear ◽  
Plate Length ◽  
Splitter Plates ◽  
Mode A

In this paper, instabilities in the flow over a circular cylinder of diameter $D$ with dual splitter plates attached to its rear surface are numerically investigated using the spectral element method. The key parameters are the splitter plate length $L$, the attachment angle $\unicode[STIX]{x1D6FC}$ and the Reynolds number $Re$. The presence of the plates was found to significantly modify the flow topology, leading to substantial changes in both the primary and secondary instabilities. The results showed that the three instability modes present in the bare circular cylinder wake still exist in the wake of the present configurations and that, in general, the occurrences of modes A and B are delayed, while the onset of mode QP is earlier in the presence of the splitter plates. Furthermore, two new synchronous modes, referred to as mode A$^{\prime }$ and mode B$^{\prime }$, are found to develop in the wake. Mode A$^{\prime }$ is similar to mode A but with a quite long critical wavelength. Mode B$^{\prime }$ shares the same spatio-temporal symmetries as mode B but has a distinct spatial structure. With the exception of the case of $L/D=0.25$, mode A$^{\prime }$ persists for all configurations investigated here and always precedes the transition through mode A. The onset of mode B$^{\prime }$ occurs for $\unicode[STIX]{x1D6FC}>20^{\circ }$ with $L/D=1.0$ and for $L/D>0.5$ with $\unicode[STIX]{x1D6FC}=60^{\circ }$. The characteristics of all the transition modes are analysed, and their similarities and differences are discussed in detail in comparison with the existing modes. In addition, the physical mechanism responsible for the instability mode B$^{\prime }$ is proposed. The weakly nonlinear feature of mode B$^{\prime }$, as well as that of mode A$^{\prime }$, is assessed by employing the Landau model. Finally, selected three-dimensional simulations are performed to confirm the existence of these two new modes and to investigate the nonlinear evolution of the three-dimensional modes.

Effect of shielding gas flow rate on arc behaviors in GMAW with single cable-typed wire

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040059
Author(s):  
Qingxian Hu ◽  
Lei Zhang ◽  
Juan Pu ◽  
Caichen Zhu
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Maximum Pressure ◽  
Arc Plasma ◽  
Shielding Gas ◽  
Gas Flow Rate

A three-dimensional numerical model of arc in gas metal arc welding (GMAW) with single cable-typed wire was established based on the theory of arc physics. The influences of different shielding gas flow rates on the features of temperature field, velocity field and pressure field were investigated. The results showed that the maximum velocity of arc plasma along radial direction and the arc pressure on the surface of workpieces were increased obviously with the increase of the shielding gas flow rate, while the arc temperature was changed little. This phenomenon was mainly attributed to the increasing collisions between arc plasmas and the self-rotation action of cable-typed wires. The arc temperature at the tip of the cable-typed wire reached the maximum. The maximum flow velocity of arc plasma was located at the tip of wire (2–8 mm). The arc pressures in the central axis reached the maximum pressure. The simulation results were in agreement with the experimental results.

scholarly journals Polymeric Ablation Induced by Free Burning Arcs in Air

2017 ◽  
Vol 4 (2) ◽  
pp. 149-152
Author(s):  
M. Bator ◽  
R. Bianchetti ◽  
P. Suetterlin
Keyword(s):  
Mass Loss ◽  
Low Voltage ◽  
Simplified Model ◽  
Contact Material ◽  
Arc Plasma ◽  
Ablation Process ◽  
Experimental Conditions ◽  
Plasma Properties ◽  
Model Geometry ◽  
Arc Current

We investigate the influence of switching arcs on different polymers and their interaction. We describe a set of experiments on a simplified model geometry typical for low voltage switchgear. In a broad range of experimental conditions and parameters such as arc current, polymeric material or contact material, the voltage, the mass loss and the corresponding pressure build-up are examined. From this raw data, we deduce the arc influence on the ablation process as well as the feedback on some arc plasma properties.

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