scholarly journals Regularities of Control of Mechanized Pulse-Arc Welding Process for Ensuring its Stability

2019 ◽  
pp. 65-76
Author(s):  
S. Yu. Maksymov ◽  
L. S. Shlapak ◽  
А. А. Havryliuk ◽  
І. М. Semianyk ◽  
V. А. Onyskiv
Keyword(s):  
Arc Welding ◽  
Low Voltage ◽  
Short Circuit ◽  
Welding Current ◽  
Short Circuit Current ◽  
Average Frequency ◽  
Maximum Value ◽  
Current Growth ◽  
Short Circuits ◽  
Electrode Metal

Mechanized arc welding in protective gases with short circuits (s.c.) is performed at moderate values of the welding current (up to 180 ... 220 A) and at the relatively low voltage (18 ... 24 V) on the arc. The main disadvantage of the process is spattering when melting an electrode metal and when transferring it to a weld bath. The elimination of disadvantages is possible through the implementation of a controlled transfer of molten electrode metal to a welding bath - due to the pulsed nature of arc burning.  At pulse-arc welding (PAW), one of the main methods of increasing the efficiency of the process is to limit the maximum value of the short-circuit current Imax s.c. by increasing the inductive resistance L in the arc-welding circuit. Proceeding from the features of mechanized arc welding, the purpose of the research is to specify the influence of the velocity of the growth of the welding current vс during the s.c. on the arc stability. The implementation of experimental work presupposes surfacing on a plate with the programming of the operating mode of the inverter at different values (9, 12, 15, 18, 21, 24, 27, 30) with the frequency f = 25 Hz and a pulse ratio C = 2. While analyzing oscillograms of welding current and processing their records, it was established that a decrease of the velocity of the welding current growth leads to a significant limitation of the maximum value of the short-circuit current. The statistical processing of the momentary values of the welding current shows that the increase in the velocity of current growth vс starting with vс = 1.23 kA / s to vс = 50 kA / s makes the average short-circuit duration 10 times shorter. At the same time, the average frequency of short circuits grows more than twice. The increase of vс leads to the destabilization of the pulse process and this is reflected in the 30-times increase of the average frequency of arc break. The increase of the energy indexes of the PAW to the Iav. = 220 ... 225 A, Uav. = 24.5 ... 25.9 V, Q ≈ 7.9 ... 8.0 kJ / cm led to the changes in the parameters which characterize the process of pulsed welding with short circuits. There is a sharp decrease in the average frequency of short circuits (2 ... 3 times as rarely) and the average duration of s.c. (twice shorter).

scholarly journals Thermal Analysis of Heat Distribution in Busbars during Rated Current Flow in Low-Voltage Industrial Switchgear

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2427
Author(s):  
Michał Szulborski ◽  
Sebastian Łapczyński ◽  
Łukasz Kolimas
Keyword(s):  
Structural Changes ◽  
Heat Dissipation ◽  
Current Flow ◽  
Low Voltage ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Coupled Analysis ◽  
Precise Representation ◽  
Transient Thermal ◽  
Halogen Free

The manuscript presents advanced coupled analysis: Maxwell 3D, Transient Thermal and Fluent CFD, at the time of a rated current occurring on the main busbars in the low-voltage switchgear. The simulations were procured in order to aid the design process of such enclosures. The analysis presented the rated current flow in the switchgear busbars, which allowed determining their temperature values. The main assumption of the simulation was measurements of temperature rise during rated current conditions. Simulating such conditions is a valuable asset in order to design better solutions for energy distribution gear. The simulation model was a precise representation of the actual prototype of the switchgear. Simulations results were validated by experimental research. The heat dissipation in busbars and switchgear housing through air convection was presented. The temperature distribution for the insulators in the rail bridge made of fireproof material was considered: halogen-free polyester. The results obtained during the simulation allowed for a detailed analysis of switchgear design and proper conclusions in practical and theoretical aspects. That helped in introducing structural changes in the prepared prototype of the switchgear at the design and construction stages. Deep analysis of the simulation results allowed for the development concerning the final prototype of the switchgear, which could be subjected to the full type tests. Additionally, short-circuit current simulations were procured and presented.

ENGINEERING ANALYSIS OF THE THREE-PHASE SHORT CIRCUIT MODE IN THE 10 KV ELECTRIC NETWORK TAKING INTO ACCOUNT THE INFLUENCE OF LOAD CURRENTS

2021 ◽  
pp. 74-83
Author(s):  
YURI D. VOLCHKOV ◽  
Keyword(s):  
Remote Monitoring ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Load Current ◽  
Electric Network ◽  
Operating Modes ◽  
Three Phase ◽  
Feed Network ◽  
Short Circuits ◽  
Switching Devices

Abstract. The load current aff ects the value of the short-circuit current in the electric network and, consequently, the voltage value. In some cases, this infl uence must be taken into account for the correct choice of switching devices, remote monitoring the operating modes of electric networks, and determining the modes. It is possible to disconnect loads connected through magnetic starters and contactors. Failure to consider the infl uence of the load current can lead to an incorrect interpretation of the identifi ed grid operating modes during remote monitoring and, as a result, incorrect dispatcher’s decisions. In addition, it is also insuffi cient to specify the choice of switching devices in the 10 kV feed network. The article describes a method for analyzing the three-phase short circuit mode in a 10 kV feed network, taking into account the infl uence of load currents. The method is exemplifi ed by the case of an actual electric network – the 10 kV ring feed network containing reclosers and receiving power from diff erent sections of lowvoltage buses of the “Kulikovskaya” 110/35/10 kV substation, belonging to the Branch of PJSC «DGC of Center”-“Orelenergo.” For this network, the values of the three-phase short-circuit currents at points with diff erent distances from the substation buses have been determined. The authors have fi guredout the values of the load currents and their shares in the total short-circuit current. The voltage values at different points of the network in the case of short circuits have also been determined. The research proves that the effect of the load current on the total short-circuit current should be taken into account for the case of remote short circuits.

scholarly journals RESEARCH OF SEAM DIMENSIONAL DEPENDENCE ON THE SHORT-CIRCUIT CURRENT IN MMA WELDING PROCESS / SIŪLĖS MATMENŲ PRIKLAUSOMYBĖS NUO TRUMPOJO JUNGIMO SROVĖS STIPRIO TYRIMAS, VIRINANT GLAISTYTAISIAIS ELEKTRODAIS

2013 ◽  
Vol 5 (6) ◽  
pp. 659-663
Author(s):  
Mindaugas Rimkus ◽  
Ivanas Višniakas ◽  
Česlovas Kazakevičius
Keyword(s):  
Arc Welding ◽  
Drop Size ◽  
Short Circuit ◽  
Welding Process ◽  
Short Circuit Current ◽  
Mma Welding ◽  
Metal Drop ◽  
Dimensional Dependence ◽  
Ridge Height ◽  
Weld Depth

In this article the changes of seams properties of steel S235J2(LST EN 10025:2004) were analyzed, produced by welding withdifferent technology are discussed. Samples were welded byhand arc welding, using AV-23 and AV-66 welding electrodes.The welded seams were made by changing short-circuit current.The duration of weld depth, ridge height, metal drop size, metaldrop frequency, short-circuit time and short-circuit current valueare determinated.The results of the research are given in graphs,final conclusions are also written. Santrauka Straipsnyje tiriami mažaanglio plieno S235J2 (LST EN 10025:2004) virintinių siūlių matmenų pokyčiai, apvirinant plieną skirtingais glaistytaisiais elektrodais įvairiais suvirinimo režimais. Tyrimų metu buvo naudojami AV-23 ir AV-66 glaistytieji elektrodai ir keičiamas trumpojo jungimo srovės stipris. Nustatytas ryšys tarp metalo įvirinimo gylio, rumbelės aukščio, išlydytų lašų dydžio ir kiekio, trumpojo jungimo trukmės ir srovės dydžio. Gauti tyrimų rezultatai, nubraižyti priklausomybių grafikai ir pateiktos išvados.

scholarly journals Bidirectional Short-Circuit Current Blocker for DC Microgrid Based on Solid-State Circuit Breaker

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 306 ◽  
Author(s):  
Lujun Wang ◽  
Boyu Feng ◽  
Yu Wang ◽  
Tiezhou Wu ◽  
Huipin Lin
Keyword(s):  
Solid State ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Rotational Inertia ◽  
Dc Microgrid ◽  
Protection Strategy ◽  
Solid State Circuit ◽  
Solid State Circuit Breaker

In order to solve the imminent problem in that the traditional protection strategy cannot meet time requirements, together with the fact that the rotational inertia of a DC microgrid is small and short-circuit fault develops rapidly, a bidirectional short-circuit current blocker (BSCCB) based on solid-state circuit breaker for a DC microgrid is proposed. Firstly, the bidirectional current blocking circuit structure is proposed based on the analysis of key components. Then, a top-level differential protection strategy is developed based on the aforementioned proposal. Finally, the performance of the blocking circuit is simulated and verified by experiments. The results show that the proposed method can block short-circuit current within 4 ms, and the response speed of the protection strategy is very fast compared with previous approaches. BSCCB also has reclosing, bidirectional blocking and energy releasing functions. The current blocker proposed in this paper can be reused multiple times and has a promising future in low-voltage DC microgrid application.

Analysis of low voltage arcing characteristic on direct short circuit through arcing thermal synchronization sensing and short circuit current

2017 ◽  
Author(s):  
Dimas Anton Asfani ◽  
I Made Yulistya Negara ◽  
Daniar Fahmi ◽  
Rifki Wiryatama ◽  
Muhammad Wildan Arinal Haq ◽  
...  
Keyword(s):  
Low Voltage ◽  
Short Circuit ◽  
Short Circuit Current

Influence of Preset Pulsed Magnetic Field on Process Stability of Short Circuiting Transfer in Gas Metal Arc Welding

2011 ◽  
Vol 339 ◽  
pp. 440-443 ◽  
Author(s):  
Shu Jun Chen ◽  
Chang Hui Liu ◽  
Yang Yu ◽  
Shao Jun Bai
Keyword(s):  
Magnetic Field ◽  
Arc Welding ◽  
Short Circuit ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Pulsed Magnetic Field ◽  
Optimum Conditions ◽  
Horizontal Magnetic Field ◽  
Metal Arc Welding ◽  
Peak Value

This study proposed preset pulsed magnetic field acting on process of the short circuiting transfer. It is a controlled horizontal magnetic field which attached at the very beginning of contact between the wire and the weld pool during welding. It was found that there exists optimum conditions of magnetic field with which preset pulsed magnetic field could accelerate the rupture of the liquid bridge and reduce the peak value of welding current in the period of short circuiting transfer. This lead to energy accumulation lowered at the last phase of the short circuiting transfer and spatter loss reduced resulting from explosive short circuit rupture, in the meantime, it could improve the regularity and stability of the short circuiting transfer as well as the weld shaping quality.

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