Electric Spark Research Articles

Calculation and experimental determination of the speed of advancement of the plasma leader channel of a pulse spark discharge in atmospheric air

Goal. Calculation and experimental determination of middle speed vL of advancement of plasma leader channel of a pulse spark discharge in the long air interval of the double-electrode discharge system (DEDS) «tip-plane». Methodology. Bases of the theoretical electrical engineering and electrophysics, electrophysics bases of technique of ultra- and high-voltage and high pulse currents, bases of high-voltage pulse technique and measuring technique. Results. The close calculation and experimental method of determination of middle speed vL of advancement of plasma leader channel of an electric pulse spark discharge is offered in the long air interval of DEDS «tip-plane». This method is based on the offered calculation empiric formula for finding of the indicated speed vL and results of decoding of oscillograms of process of cut of in-use standard interconnect аperiodic pulse of over- and high-voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity at an electric hasp in indicated DEDS of long air intervals with their minimum length of lmin, numeral making 1,5 m (first case) and 3 m (second case). It is shown that middle speed vL of advancement in atmospheric air of front of plasma channel of positive leader of an electric pulse spark discharge in probed DEDS «tip-plane» for two considered applied cases at lmin=1,5 m of lmin=3 m numeral makes approximately vL≈(1±0,03)∙105 m/s. The found numeral value of this speed vL well coincides with the known experimental information for speed of advancement of vL≈105 m/s in atmospheric air of plasma channel of negative leader for a long storm spark discharge in DEDS «charged cloud-earth». It is set that for the standard interconnect аperiodic pulse of high- and ultra- voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity middle value of aggressive strength Ed of high pulse electric field in the air interval of probed DEDS «tip-plane» numeral makes minimum length of lmin=1,5 m near Ed1≈360,8 kV/m, and for his minimum length of lmin=3 m of − Ed2≈313,4 kV/m. Originality. The comfortable is developed in the use and reliable in practical realization technicians-and-engineers calculation and experimental method of research in the conditions of high-voltage electrophysics laboratory of difficult electro-discharge processes of development of leader hasp of long air intervals and determination of minimum electric durability of air insulation of electrical power engineering and electrophysics equipment on working voltage of classes of 330-1150 kV. Practical value. Application in area of industrial electrical power engineering and high-voltage pulse technique of the got numeral electrophysics results and offered calculation and experimental method of determination of middle speed vL of advancement in atmospheric air of plasma channel of leader of a long spark discharge will allow, from one side, to deepen our scientific knowledges about a long electric pulse spark discharge in an air dielectric, and, from other side, to develop high-voltage electrical power engineering and electrophysics devices with enhanceable reliability of their work both in normal operation and malfunctions.

Research on the grinding performance of grinding wheel in the initial grinding stage after electric spark dressing of grinding wheel

Research on the grinding performance of grinding wheel in the initial grinding stage after electric spark dressing of grinding wheel

Construction and analysis of a mini Tesla coil as an educational support elemento

This article presents an assembly manual for a Tesla coil prototype using low-cost materials, developed to meet the needs of public education in Brazil. Public education in Brazil faces significant challenges, including a lack of structural and teaching resources. This makes it difficult to teach complex subjects such as Physics, which require experimental resources to understand the concepts. The Tesla coil prototype is built from low-cost materials such as acrylic, PVC, copper and electronic components. The coil has a base with 26 concentric circles, which allows vertical mobility. For qualitative analysis, the coil is used to ionize a fluorescent lamp, which turns on only when approached. For quantitative analysis, the coil is coupled to a Gaussometer, which measures the magnetic field values at different distances from the coil. In other words, we model the relationship between the distance from the sensor to the coil and the value of the measured magnetic field. Tests carried out in two public schools demonstrated that the coil is capable of arousing students' curiosity and interest in experimental Physics. The students were impressed by the effect of the electrical sparks produced by the coil, and showed interest in learning more about the concepts involved. The prototype presented is a valuable tool for teaching Physics in public high schools. The coil is affordable, easy to build and can be used to carry out experiments in Physics classes, electives and in-depth courses.

Response surface methodology-based machining parameter optimisation for electrical discharge machining of stainless steel of grade AISI 4140

Electrical sparks are used in the unconventional technique of electrical discharge machining (EDM) to remove material from a workpiece. In the industrial sector, this method is often used to manufacture tough, challenging-to-machine materials like stainless steel. In this research works, we look at how to best machine stainless steel with an AISI 4140 grade, which is widely used in the aerospace and automotive sectors. The process variables, such as pulse on-time, pulse off-time, and peak current, have a big influence on the effectiveness and quality of the machining. To investigate the impacts of these factors on the machining properties, including material removal rate, tool wear rate, surface roughness, and microstructure, a systematic experimental examination is carried out in this project. The findings indicate that the ideal parameter combinations for getting the highest machining performance rely on the particular needs and limitations of the application. Various advanced optimisation techniques, such as Response Surface Methodology, are applied and compared to facilitate parameter optimisation. Moreover, the effect of a novel surface modification technique, which combines EDM with laser irradiation, on the surface properties of AISI 4140 steel is investigated. The results of this research contribute to the creation of effective and sustainable machining procedures for advanced materials by offering useful insights into the optimisation of EDM parameters for cutting AISI 4140 steel.

Experimental Study on Stability Analysis of Shallow-Buried Metro Station Hard Rock Excavation under Blasting Vibration Effect

Abstract By considering a certain metro station of Qingdao Metro Line 4 as the research object, a three-dimensional geotechnical testing model has been developed to analyze the stress and deformation characteristics of the surrounding rocks under blasting vibration effect. The simulation of the surrounding rock blasting process is achieved through an electric spark source. We conducted simulation tests on the excavation stability of shallow-buried hard rock metro stations with and without considering blasting damage effects, respectively. The stress, displacement, and primary support stress changing laws of the surrounding rock under different overburden thicknesses using the arch cover method and the primary support arch cover method have been revealed. Finally, we analyzed the applicability of the primary support arch cover method in terms of vault settlement, clearance convergence, and floor heave. Results show that the surrounding rock of the arch has roughly gone through three deformation stages, namely a slow deformation stage, rapid deformation stage, and stable deformation stage. Whether it is blasting excavation or non-blasting excavation, the settlement of the arch is within a safe and controllable range. Because of the refinement of the excavation process by the primary support arch cover method, the stress release is relatively stable throughout the entire excavation process, but the significant impact of blasting vibration on the surrounding rock cannot be ignored. The excavating of the left and right guide holes is the key process for the displacement and stress variation. The deformation and stress generated by the arch cover method have a small difference compared to the deformation and stress generated by the primary support arch cover method, indicating that the latter excavation method can be used under current engineering geological conditions. No large-area collapse and instability occurred in the experimental process, which provides a theoretical basis for similar projects.

Exploring the Influence of Vibration Impact and Electric Spark on Aluminum Alloy Stress Fields

Vibration Impact Compound Electric Spark (VIES) is a technology that combines the advantages of vibration impact and electric spark surface enhancement. Due to its simple process, cost-effectiveness, and superior efficiency, it has attracted considerable attention in industrial applications. Through finite element simulation analysis, this study designed orthogonal experiments to explore the impact of VIES on the stress field distribution of aluminum alloy plates. The results indicate that factors such as impact frequency, impact height, and electric current have a certain influence on the distribution of longitudinal residual pressure stress in aluminum alloy plates. The experiments indicate that increasing the impact height within a certain range leads to an increase in residual stress at the impact site, but the depth of the compression stress layer decreases. Meanwhile, increasing the impact frequency increases the residual stress at the impact site, while the depth of the compression stress layer remains constant. In summary, both impact height and frequency have an impact on the stress in aluminum alloy plates. Additionally, orthogonal experimental results suggest that electric current has no significant effect on the stress field.

A generalized physical principle of development of plasma channel of a high-voltage pulse spark discharge in a dielectric

Goal. Development of the generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge in the homogeneous dielectric of the different aggregate state. Methodology. Basis of physical optics, theoretical electrical engineering, electrophysics bases of technique of high-voltage and large pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Development of physical principle of development of plasma channel of an electric pulse spark discharge is executed in a homogeneous gas dielectric on the applied example of the use in calculations and experiments of the double-electrode discharge system (DEDS) with a long air interval, testing action of standard interconnect аperiodic pulse of high-voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity. The generalized formula is got for the calculation of total length of lc of the real way of development of an pulse spark discharge in an air dielectric, which allowed to formulate the offered physical principle in the following kind: «The plasma channel of an pulse spark discharge in a gas dielectric spreads from one of its points to other after a way length of lc, providing the least falling on it of electric voltage of Uc». It is shown that this principle in the first approaching can be applied and to the homogeneous liquid and hard dielectrics. Comparison of the developed physical principle of distribution of plasma channel of an electrical spark discharge is executed in a dielectrical environment with fundamental Fermat physical principle (a law) for distribution of light in an optically transparent environment, which specifies on mathematical likeness and closeness on destiny of these physical principles. Calculation estimations of falling of electric voltage of Uc on total length of lc of the real zigzag way of development in the air dielectric of DEDS a «edge-plane» with the least length of its discharge interval of lmin=1,5 m is presented, that a value Uc does not exceed 9 % from the experimental level of aggressive voltage of Umd≈611,6 кV in this DEDS for the аperiodic pulse of voltage of Tm/Тd≈200 μs/1990 μs. It is set that the estimated time of td advancement of leader channel of electric pulse discharge in air DEDS (lmin=1,5 m) on its real way total length of lc≈1,53 m makes td≈15,3 μs, and experimental duration of cut of Tdc of the indicated аperiodic impulse of voltage utilized in experiments, characterizing time of short circuit by the plasma channel of discharge of air interval in DEDS, appears equal Тdc≈td≈17 μs. Originality. The generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge is first developed in the homogeneous dielectric of the different aggregate state. Practical value. Application in electrical engineering practice and high-voltage pulse technique of the offered principle of distribution in the dielectrics of plasma channel of an pulse spark discharge will allow to develop both new and to perfect the existent methods of computer design of electro-discharge processes in the gas, liquid and hard insulation of different high-voltage electrical power engineering and electrophysics devices, directed on the increase of reliability of their operation.

Study of mass transfer during electric spark processing of steel with tungsten anode material

Changes in the specific masses of electrodes were studied during electric spark processing of SCMnCr3 steel with anode material made of WP tungsten on an Alier-31 installation. Predominant erosion at high cathode processing energies is due to the difference in the melting/evaporation temperatures of the cathode substrate (iron) and anode (tungsten) materials. The influence of the energy of the electric spark discharge is associated with a change in the volume of the electrodes converted into liquid and gaseous states. The amplitude of the electrode-anode oscillations is influenced by changing the average volume of the interelectrode gap.

The Importance of using the High Voltage Pulse Generator in the Certification Process of Electric Motors with the type of Protection Increased Safety used in Potentially Explosive Atmosphere

The purpose of this paper is to present the importance of the specific tests for electric motors with type of protection increased safety „e” designed to be used in explosive atmosphere. This paper presents the voltage impulse ignition test applicable to electric motors with increased safety protection type. Due to the fact that electric motors with type of protection Increased Safety, whose supply voltage exceeds 1000 V, presents a high risk of sparks occurring in windings, it is necessary to perform tests to verify that the insulation of the windings is adequate and does not lead to electric discharge (through electric springs or sparks) at winding levels Evaluation of explosion-proof protected electrical equipment in scope of certification is extremely important considering the risk of explosion that has to be minimized in order to ensure life safety and health of workers and to prevent damaging of property and the environment, as well as free movement of goods when they meet the essential safety requirements at European level. The standard SR EN 60079-0 (Explosive atmospheres Part 0: General requirements) and one or more of the standards containing the specific requirements for the type(s) of protection applied to equipment (ex. SR EN 60079-7 for the type of protection increased safety “e”), are used to perform the assessment.

ПРИМЕНЕНИЕ ВТОРИЧНЫХ ПОРОШКОВЫХ МАТЕРИАЛОВ ДЛЯ ВОССТАНОВЛЕНИЯ БРОНЗОВЫХ ДЕТАЛЕЙ ГИДРОМАШИН

During the operation of agricultural machinery, machine parts and their connections lose their operability, which requires their replacement. The cost of restoration is 50-60 percent of the cost of a new part. The presence of non-ferrous metal and alloy parts in the equipment, and in particular bronze, makes the issue of restoration even more urgent due to the high cost of such parts. Methods using powder materials are particularly successful in restoring worn parts. It is characteristic that in order to reduce the cost of such technologies, it is possible to resort to recycling of metal waste and obtain powder by electroerosive dispersion without special economic costs. (Research purpose) The research purpose is studying the restoration of bronze parts of hydraulic machines with secondary powder materials and analyzing the tribotechnical indicators of the coatings obtained. (Materials and methods) The following equipment was used in the work: an Elitron-52B pulse generator, a scanning electron microscope, a spark plasma sintering unit, an electric spark alloying unit, an X-ray fluorescence spectrometer, a metallographic microscope, a tribometer, analytical scales, a drying cabinet, a set of sieves. (Results and discussion) Electrodes were made from bronze powder obtained by the method of electroerosive dispersion. Using electric spark alloying, samples with coatings from a standard and a new obtained electrode were created. The tribotechnical properties of these coatings were compared. Metallographic and chemical analyses were performed. (Conclusions) The coatings obtained with the new electrode showed the best tribotechnical characteristics in dry friction. At boundary friction, their performance was worse, which may be due to an incorrect choice of lubrication, modes of electric spark alloying and a violation of the technology for obtaining the electrode itself. In general, the use of secondary powder materials for the restoration of bronze parts is relevant.

Фазовый состав и морфология поверхности бронзы БрО10С10 после ее электроискровой обработки анодным материалом аналогичного состава

The coating on the surface of BrO10C10 bronze was studied by scanning electron microscopy and X-ray diffractometry. It was obtained by electrospark processing with an anode material with a composition similar to that of the substrate. X-ray studies of the phase composition revealed the presence of phases of the “copper – tin” system (Cu, α-(Cu; Sn), Cu3Sn, ε-Cu3Sn and Cu5.6Sn) and lead. The incorporation of atmospheric elements and initial bronze components into lead leads to the formation of regions with a distorted crystal lattice. An increase in the energy of a single pulse of an electric spark discharge is accompanied by a decrease in the α-(Cu; Sn) phase and an increase in the content of ε-Cu3Sn and Cu5.6Sn. The ratio of intensities indicates the absence of a predominant orientation of growth (texture) in the electrospark coating. Scanning electron microscopy data indicate the presence of melted areas, pores, spherical and oval inclusions, irregularly shaped particles, cracks, rounded pits, etc. in the surface layer. The main reason for the presence of melted areas is high temperatures in the interelectrode region during an electric spark discharge. The appearance of surface cracks is primarily associated with the occurrence of high thermal stresses and interelectrode mechanical contact. The presence of spherical/oval particles is a consequence of the interaction of liquid droplets with the surface of the cathode substrate. Irregularly shaped particles appear as a result of explosive emission from the edges of the erosion crater of the anode material.

Restoration of spline surface of axial pump drive shaft by electric spark doping

This paper considers the possibility of restoring the splined surfaces of the drive shafts of axial pumps having specific wear by the electric spark doping (EIL) method, with the creation of coatings on their working surfaces, with corresponding mechanical characteristics. Electrode materials and processing modes are selected. Studies were carried out to determine the processing modes to obtain the optimal roughness of the applied coating. Keywords axial pump, electric spark doping, reduction, electrode materials, reduced energy, roughness

Electric spark alloying of steel, titanium and niobium alloys using rotating electrode method

The article presents the results of a study of electrospark coatings on metals and alloys using the rotating electrode method. The influence of various parameters on the formation of an electrospark coating on steel 20, titanium VT1-0, niobium and niobium alloy 5VMTs, on titanium VT1-0, niobium and niobium alloy 5VMTs with subsequent siliconization has been studied. The dependences of the growth of the thickness of the electrospark coating with increasing doping time, current in the circuit, and electrode rotation speed were obtained. It has been established that with increasing thickness of the electrospark coating, the thickness of the silicide layer increases. Electric spark alloying leads to an increase in the heat resistance of steel 20 with an aluminum coating by 1.5—3.0 times, of titanium by 2—9 times, and of titanium with a nichrome coating by 2 times. The heat resistance of titanium with a copper electrospark coating after siliconization increases up to 2—10 times, depending on the thickness of the electrospark layer and the siliconization temperature.

Parametric analysis and its effect on machinability for Incoloy 800 with copper electrode

In Electric Spark Machining, choice of manufacturing constraints is a necessary feature. This Electrical Spark Machining is an advanced process in all manufacturing processes. For the manufacturing of sophisticated parts, which require accurate machining that time Electric Discharge Machining used. A super alloy, heat-treated tool steel, ceramics, heat resistance steels etc. which are tough to machining. For this, we use Electric Discharge Machining which also known as Electric Spark Machining. Incoloy alloy set in the group of super stainless steels. The main element of this Incoloy alloy is nickel-chromium-iron with other extra copper, molybdenum metal. High solidity at high peak temperature and super resist of erosion is the main feature of Incoloy alloy. Vast application of Incoloy 800 is like Heat exchangers, Carburizing equipments, Heating elements and nuclear steam generator tubing. In our research, we use hollow, flat, convex and concave electrode profile for machining of Incoloy 800.MRR and TWR are the parameters we analyze after the experiment.

Study on the influence of processing technology on the properties of 2024-T3 aluminum alloy

2024-T3 aluminum alloy is widely recognized for its low density and excellent mechanical properties. However, it has some shortcomings at high temperatures. Using Abaqus simulation technology, the surface heat source during the VIES (Variable Input Energy Source) treatment process was simulated, with the energy originating from the discharge channel. Through orthogonal experimental methods, it was indicated that the distribution and depth of the molten pool varied under different process parameters. Meanwhile, electric spark surface strengthening mainly affected the surface of the workpiece, with minimal impact on the internal structure. When the impact frequency is constant, increasing the input current enlarges the maximum heat flux density (Qmax) at the center, leading to an expansion of the molten pool area. Conversely, when the input current is constant, increasing the impact frequency shortens the contact time between the electric spark and the plate, resulting in reduced heat input from the electric spark. Consequently, the surface molten pool area decreases.

Effect of thermal poling in sodium tantalum phosphate glass-ceramics

Eu3+-doped sodium tantalum phosphate glass-ceramics containing bronze -like perovskite crystalline phase Na2Ta8O21 were obtained with different crystalline states (degree of crystallinity and average crystallite size) by a suitable control of the heat-treatment time and temperature of the precursor glass. Luminescence properties of Eu3+ in these materials are in agreement with a progressive insertion of the rare earth ions in the sodium tantalate Na2Ta8O21 phase, as probed by a clear decrease of the intensity ratio between transitions [5D0 →] 7F2/7F1 and narrowing of characteristic emission bands. Thermal poling insights were performed on these glassy and glass-ceramic materials and the experimental conditions had to be carefully optimized in the glass-ceramics to avoid electrical sparks and sample break associated with dielectric breakdown of the samples. Suitable and stable thermal poling treatments could be performed at 250 °C and 900 V under N2 atmosphere on both glass and glass-ceramics. These first insights pointed out a lower migration kinetic of sodium ions when compared to the precursor glass as well as a lower content of depleted ions, since part of sodium is supposed to be “frozen” inside the crystalline phase in glass-ceramics. Despite these lower kinetic poling conditions, a poled sodium depleted layer whose thickness depends on the poling time was successfully formed at the anode side. Reflectance infrared spectroscopy was also used to investigate the structural changes in the poled layer. These IR data pointed out that structural changes induced by thermal poling are mainly promoted in the phosphate network rather than tantalate units in both glass and glass-ceramics in agreement with a selective sodium migration from the remaining glassy phase. Macroscopic induced SHG measured by the Maker fringes technique is also consistent with the EFISH model and quantitative simulations of these data allowed to estimate second order nonlinear optical susceptibilities χ(2) ten to twenty times lower in the glass-ceramics than in the precursor glass. Such electric behavior is discussed in terms of dielectric properties of heterogeneous materials and interfacial polarization mechanisms between crystallites and glassy phase.

EDM Electrode Design and Analysis to Enhance Process Performance

Electric discharge machining (EDM) is regarded as one of the most energy-efficient manufacturing processes for exceptionally accurate processing of any electrically conductive material, regardless of mechanical properties. EDM is a non-contact process utilized in various industries, including aerospace, industrial, instruments, molds, dies, and medical tools; also, it is beneficial for hard materials with simple or proficient geometries and shapes. Although EDM is for machining "difficult to machine" metals, such as those used in the mold and die industries, metal properties indicate potential capability in the domain of surface modification due to the electrical spark between the tool and the work material. This paper investigates the machining of Alloy steel X210 by using the most affecting parameters and how electrode angles contribute to responses, as MRR, Electrode wear ratio, and surface finish, which the manufacturing industry uses to make die tools, molds, automotive parts, and other products. Electrodes with angles of 0o and 90o are used to machine workpieces using WEDM (dk7740). Electrode Angle, peak discharge current, pulse-on time, and pulse-off time were controllable parameters in this study. While all other criteria are constant, variables have been studied. The effects of the four aspects on the four variables were statistically analyzed using ANOVA by MINITAB. Regression models for the responses were developed. Regression mathematical models have been developed for Alloy steel X210 workpieces to increase productivity and industry results.

A Hybrid Optimization-Based Artificial Neural Network Model for Wireless Power Transfer in Electric Vehicles

Electric Vehicles (EVs) are powered by a battery mounted in the vehicle, which powers the motor and drives the wheels. Most commercial EVs can be charged by plugging them into a charging station. Such conductive recharging has various drawbacks, including physical plugging of the cable, safety concerns, and charging time. Manually charging EVs might be dangerous due to the chance of an electric spark or disaster. Advances in Wireless Power Transfer (WPT) demonstrate the capacity to transfer significant amounts of electricity over short and medium-range distances. The ultimate purpose of this paper is to improve the efficacy of electric car wireless charging systems. Here, a hybrid optimization-based Artificial Neural Network (ANN) model is applied to improve the efficacy of the WPT model in EVs. To optimize the weights of the ANN classifier, a hybrid approach termed as Grasshopper-Assisted Elephant Herd Optimization (GA-EHO) method is proposed. The GA-EHO is derived through the hybridization of Elephant Herd Optimization (EHO) Algorithm and the Grasshopper Optimization Algorithm (GOA) techniques. Finally, the experimental study reveals that at 70% learning rate, the proposed ANN system achieves a minimal MSE value of 0.0528, which is lower than other current classifiers, such as SVM, LSTM, and CNN.

Multi objective optimization of EDM process parameters for HCHCr steel

Electric discharge machining (EDM) or spark machining involves controlled erosion of electrically conducting materials by an interrupted, repetitive electric spark creating discharge between the cathode- tool and anode- work-piece, separated by a dielectric fluid medium. The objective of this work is to study the influence of machining characteristics during EDM of high carbon and high chromium steel (HCHCr) with copper electrode. EDM of HCHCr steel is conducted according to Taguchi orthogonal array (OA) design of experiment to evaluate the material removal rate (MRR), tool wear rate (TWR) and surface finish (Ra).The experiments are conducted on die-sinking EDM with varying current, voltage, and pulse-on-time to measure the above responses. Finally, the multi objective optimization technique namely principal component analysis (PCA) is used for optimizing the process parameters. The experimental results indicate the optimum parameters as: current 9 Amps, pulse-on time 15 µs and pulse-off time 10 µs.

Increasing the Overhaul Life of Hydraulic Distributors by Electric Spark Treatment

Increasing the Overhaul Life of Hydraulic Distributors by Electric Spark Treatment