Current Lead Research Articles

Self-Protecting HTS Current Lead-Demonstration of a New Technology

A straight forward solution to reduce the heat load of Current Leads to superconducting magnets operating at 4 K is the use of high temperature superconductors (HTS) thereby eliminating the ohmic heating at the range below 50–77 K. The heat input from the current leads is then determined by heat conduction in the HTS section only, leading to some factor 10 reduction in the heat load in comparison to fully normal conducting conventional leads. Modern HTS conductors demonstrate extremely high current density and further decrease of the current lead heat load is limited not by the material properties but by the requirement of robustness and reliable protection of the leads in the case of cryogenic failures in order to avoid lead burnout. While accelerator magnets are designed for a fast dump at quench events within a fraction of a second, larger stored energy magnets like detector magnets may have discharge times of tens of seconds or even more. In this case the HTS part of the lead has to withstand the ohmic heating for a relatively long time and this requirement then determines the heat input at operation conditions. A new idea to reduce the heat load while keeping full reliability of the HTS leads is using a thermo-mechanical switch that is connected electrically in parallel to the HTS lead section. In the case of a quench in the HTS lead section, by using the differential thermal expansion between materials, the switch turns on and the overheated section is bypassed by the high cross-section of the conductive part of the switch. We wish to use this new technology for the first time for the BabyIAXO detector magnet. In this paper the design and test of the first and unique Self-Protecting HTS Current Lead with a current rating of 800 A is presented.

Расчет магнитогидродинамических параметров работы электролизеров с различным типом катодного кожуха

The aim of the research was to analyse the influence of cathode casing design on electrolytic cells with self-baking anodes taking the following magnetohydrodynamic characteristics into account: magnetic field, speed and circulation direction of cathode metal, margin of magnetohydrodynamic stability. The most common type of electrolysers having a Söderberg anode and S-8BM top current lead, for which both counterforce and cradle cathode shell types were used, was taken as an object of study. To simulate the magnetohydrodynamic phenomena occurring in the electrolyser, we used the specialised Blums v5.07 computer program. The following settings were identical for both versions of the models: type of bus, anode assembly parameters, cathode material properties, formation features of the anode mass sintering cone and form of the working space. The calculation of the magnetic field of the electrolyser was carried out using an analytical research method based on the integration of the Poisson (for regions occupied by current) and Laplace (for regions not occupied by current) equations. According to calculations of the speeds and directions of movement of the cathode metal, both types of cathode casing of the electrolyser were shown to be characterised by a four-circuit circulation system, determined by the corresponding location of the anode risers at the inlet and outlet ends of the electrolyser. The results of mathematical modelling show that for electrolysers with a cathode shell of the cradle type, the transverse and vertical components of the magnetic field are less compensated than for cells having a counterforce shell, which affects the average speeds of the cathode metal: circulation speeds will be 0.02 cm / s below. However, the margin of magnetohydrodynamic stability is almost identical for both cathode shell designs. With the same shape of the working space, as well as interpolar distance (41 mm) and metal level (34 cm), the calculated margin of magneto-hydrodynamic stability was 360-380 mV.

SUN-660 Appetite Suppressing Effects of Glucoregulatory Chimeric Peptides Devoid of Nausea

Current treatments for type 2 diabetes (T2D) and obesity do not reliably achieve long-term weight-loss and up to 50% of patients experience nausea and vomiting. Thus, there is a critical need for obesity medications that provide glycemic control with enhanced hypophagic response without nausea. Based on rational design and in silico modelling of the glucagon-like peptide 1-receptor agonist (GLP1RA) exendin-4 (Ex4) and the neuropeptide Y2 receptor (Y2R) agonist peptide YY (PYY) 3-36, our group has developed and tested several new monomeric chimeric peptides that display dual agonism of the anorectic Y2R and the glucoregulatory GLP1R. In addition, we explored a third agonistic behavior at the neuropeptide Y1 receptor (Y1R), which potentially relates to pancreatic beta-cell protection. Our current lead, GEP44, binds and robustly activates the Y2R, Y1R, and GLP1R. In our experiments, half maximal effective concentration (EC50) values for GEP44 were 10 nM at Y2R, 24 nM at Y1R, and 330 pM at GLP1R for dose responses of cell-based fluorescence resonance energy transfer assays. For the control substrates PYY3-36, PYY1-36, and Ex4, EC50 values were 16 nM, 12 nM, and 16 pM at the Y2R, Y1R, and GLP1R, respectively. We tested effects of daily injections of these chimeric peptides in adult Sprague-Dawley rats on food intake (FI), body weight (BW) changes, blood glucose levels and an indicator of nausea (kaolin intake). GEP44 produced profound reduction in FI (2-d average GEP44 at 20 nmol/kg FI -71%; Ex-4 20 nmol/kg FI -40%). Anorectic doses of GEP44 did not trigger a pica response assessed by kaolin consumption in treated rats, while in Ex-4 treated rats, kaolin consumption accounted for 28% of total daily solid intake, indicating a clear nausea response. During 11 d of treatment with GEP44, FI was consistently reduced resulting in a significantly stronger reduction of BW compared to Ex4 at the end of treatment (GEP44 -7.6%, Ex4 -3.7%, p<0.05). Furthermore, 5-day injections of GEP44 showed greater reduction of glucose levels than for Ex4 in diet induced obese rats receiving intraperitoneal glucose. These results were supported by results generated using a customized perifusion system that demonstrated acute stimulation of insulin secretion by exposure of isolated rodent and human islets to GEP44 and Ex4 (both p<0.01 vs. vehicle). In conclusion, simultaneously targeting serial anorectic pathways with single molecule chimeric peptides developed by our group can address multiple coexisting conditions, namely obesity and T2D, to more efficaciously reduce FI, BW and blood glucose levels thereby reducing off target effects.

Inverse Agonism of Cannabinoid Receptor Type 2 Confers Anti-inflammatory and Neuroprotective Effects Following Status Epileptics.

Prolonged status epilepticus (SE) in humans causes high mortality and brain inflammation-associated neuronal injury and morbidity in survivors. Currently, the only effective treatment is to terminate the seizures swiftly to prevent brain damage. However, reliance on acute therapies alone would be imprudent due to the required short response time. Follow-on therapies that can be delivered well after the SE onset are in an urgent need. Cannabinoid receptor type 2 (CB2), a G protein-coupled receptor that can be expressed by activated brain microglia, has emerged as an appealing anti-inflammatory target for brain conditions. In the current study, we reported that the CB2 inverse agonism by our current lead compound SMM-189 largely prevented the rat primary microglia-mediated inflammation and showed moderate neuroprotection against N-methyl-D-aspartic acid (NMDA) receptor-mediated excitotoxicity in rat primary hippocampal cultures containing both neurons and glia. Using a classical mouse model of epilepsy, in which SE was induced by systemic administration of kainate (30mg/kg, i.p.) and proceeded for 1h, we demonstrated that SE downregulated the CB1 but slightly upregulated CB2 receptor in the hippocampus. Transient treatment with SMM-189 (6mg/kg, i.p., b.i.d.) after the SE was interrupted by diazepam (10mg/kg, i.p.) prevented the seizure-induced cytokine surge in the brain, neuronal death, and behavioral impairments 24h after SE. Our results suggest that CB2 inverse agonism might provide an adjunctive anti-inflammatory therapy that can be delivered hours after SE onset, together with NMDA receptor blockers and first-line anti-convulsants, to reduce brain injury and functional deficits following prolonged seizures.

Abstract IA04: Targeting RAS for anticancer therapy

Abstract RAS is the most frequently activated oncoprotein in human cancer. Mutations in KRAS are prevalent in pancreatic, colon, and lung cancer. Despite the need for anti-RAS therapies, there are no clinically successful targeted therapies for RAS. We will present efforts to characterize KRAS G12C covalent inhibitors and compounds that bind to the KRAS P1 pocket. In addition, the Clark lab (U. of Louisville) has identified novel small molecules that bind and directly inhibit RAS function. Uniquely, the current lead compound binds preferentially to the activated form of RAS. It blocks the interaction of RAS with downstream effectors and suppresses the transforming activity of RAS in soft agar assays. The best compounds give an IC50 of ~500 nM in vitro. The inhibitor is active in vivo and suppresses growth of RAS-driven xenografts in NRG mice. There is no detectable toxicity. We have initiated efforts to solve the structure of these inhibitors in complex with RAS, to characterize the nucleotide dependence as well as inhibition of RAS interactions with regulatory and effector proteins in vitro using X-ray crystallography in combination with NMR, biochemical, and bioactivity assays. Results from these analyses will aid in elucidating the specificity and the mechanism of action needed to optimize the inhibitors and facilitate development into a drug candidate. Citation Format: Sharon Campbell, Leiah Carey, Ajit Prakash, Geoff Clark, Sarah Scarry, Jeff Aube. Targeting RAS for anticancer therapy [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA04.

PIG-A gene mutation as a genotoxicity biomarker in human population studies: An investigation in lead-exposed workers.

The rodent Pig-a gene mutation assay has demonstrated remarkable sensitivity in identifying in vivo mutagens, while much less is known about the value of the human PIG-A assay for risk assessment. To obtain more evidence of its potential as a predictive biomarker for carcinogen exposure, we investigated PIG-A mutant frequencies (MFs), along with performing the Comet assay and micronucleus (MN) test, in 267 workers occupationally exposed to lead. Multivariate Poisson regression showed that total red blood cell PIG-A MFs were significantly higher in lead-exposed workers (10.90 ± 10.7 × 10-6 ) than in a general population that we studied previously (5.25 ± 3.6 × 10-6 ) (p < .0001). In contrast, there was no increase in lymphocyte MN frequency or in DNA damage as measured by percentage comet tail intensity in whole blood cells. Current year worker blood lead levels (BLL), an exposure biomarker, were elevated (232.6 ± 104.6 μg/L, median: 225.4 μg/L); a cumulative blood lead index (CBLI) also was calculated based on a combination of current and historical worker BLL data. Chi-square testing indicated that PIG-A MFs were significantly related to CBLI (p = .0249), but independent of current year BLL (p = .4276). However, % comet tail intensity and MN frequencies were better associated with current year BLL than CBLI. This study indicates that the PIG-A assay could serve as biomarker to detect the genotoxic effects of lead exposure and demonstrates that a battery of genotoxicity biomarkers having mechanistic complementarity may be useful for comprehensively monitoring human carcinogenic risk.

Photoacoustic detection of acetone in N2 and synthetic air using a high power UV LED

The performance of a photoacoustic trace gas sensor for the detection of acetone in N2 and synthetic air is reported. The sensor system utilises an amplitude modulated UV LED. The light source has an emission maximum at 278 nm and a maximum CW output power of 300 mW according to the datasheet. Three different collimating and focusing approaches have been investigated to guide the highly divergent LED light into the acoustic resonator of the photoacoustic measurement cell. A 3D printed aluminium cell was designed to optimize light coupling by simultaneously minimizing the photoacoustic background signal generation. Hence, the diameter of the resonator was set to a comparable large diameter of 10 mm and the inner walls of the resonator were mirror polished. The additive manufacturing procedure allowed for integration of a spirally formed gas channel, enabling gas heating prior to detection. The sensor performance was investigated by measuring acetone in N2 and synthetic air at different concentrations. The UV LED current was set to 86 % of the maximum value according to the datasheet of the light source in order to increase the lifetime and thermal stability. An Allan-Werle deviation analysis validates a stable sensor performance. The limit of detection (LoD) was determined at a 3σ noise level with a 10 s lock-in amplifier time constant by sampling data points over 20 s with a data acquisition rate of 5 Hz. LoDs of 80.8 ppbV and 19.6 ppbV were obtained for acetone in N2 and synthetic air, respectively.

Practical Estimation of HTS Dynamo Losses

In High Temperature Superconducting (HTS) DC magnet applications, the current leads contribute a significant fraction of the cooling load. Higher current operation requires larger current leads and a larger thermal bridge into the cryogenic superconducting components. Removal of current leads into the cryogenic environment would lead to a significant reduction in cooling load and hence reduce ongoing operation costs. Superconducting dynamos are a non-contact method of energising HTS coils, capable of producing significant currents in the connected superconducting circuits that exceed usual current lead arrangements. The use of superconducting dynamos has the potential to reduce the size and mass of a complete magnet system by replacing the power source, current leads, and cryocooler. Previous work on superconducting dynamos has focused on driving larger currents, and understanding the underlying physical principles of operation, but has not investigated the AC losses associated with operation. In this work the losses of a kA class multi-stator squirrel-cage superconducting dynamo are investigated experimentally, and compared to the losses expected in the conventional copper current lead based energisation method. The thermal load associated with conduction cooled copper leads prevents practical application of kilo-amp class dc HTS magnets, however we demonstrated the feasibility of using this superconducting dynamo as an energisation method to enable feasible portable high current HTS magnet systems.

Pan Aurora Kinase Inhibitor: A Promising Targeted-Therapy in Dedifferentiated Liposarcomas With Differential Efficiency Depending on Sarcoma Molecular Profile.

Soft tissue sarcoma (STS) are rare and aggressive tumours. Their classification includes numerous histological subtypes of frequent poor prognosis. Liposarcomas (LPS) are the most frequent type among them, and the aggressiveness and deep localization of dedifferentiated LPS are linked to high levels of recurrence. Current treatments available today lead to five-year overall survival has remained stuck around 60–70% for the past three decades. Here, we highlight a correlation between Aurora kinasa A (AURKA) and AURKB mRNA overexpression and a low metastasis-free survival. AURKA and AURKB expression analysis at genomic and protein level on a 9-STS cell lines panel highlighted STS heterogeneity, especially in LPS subtype. AURKA and AURKB inhibition by RNAi and drug targeting with AMG 900, a pan Aurora Kinase inhibitor, in four LPS cell lines reduces cell survival and clonogenic proliferation, inducing apoptosis and polyploidy. When combined with doxorubicin, the standard treatment in STS, aurora kinases inhibitor can be considered as an enhancer of standard treatment or as an independent drug. Kinome analysis suggested its effect was linked to the inhibition of the MAP-kinase pathway, with differential drug resistance profiles depending on molecular characteristics of the tumor. Aurora Kinase inhibition by AMG 900 could be a promising therapy in STS.

Nanomolar detection of lead using electrochemical methods based on a novel phthalocyanine

4-4-[(Bromo-phenylimino)-methyl]-2-methoxy-phenoxy-phthalocyanine (CoTBrIMPPc) complex was synthesized and characterized by different spectroscopic as well as analytical techniques for the first time. The iminephthalocyanine derivative displayed redox peaks ascribed to cobalt (Co+2/Co+1) metal and phthalocyanine ligand (Pc−2/Pc−3). The (CoTBrIMPPc) complex was immobilized by drop coating method on the glassy carbon surface and the modified electrode was utilised for detecting lead (Pb) at nanomolar concentration level by voltammetry and amperometric methods. The cyclic voltammetric method showed linearity in the 100–1000 nmol L−1 range with the limit of detection (LOD) 37 nmol L−1. The addition of lead species did not show the considerable amperometric current response under normal amperometric conditions and hence experiments were performed by the modified methodology. Amperometry technique showed linearity in the 500 to 3000 nmol L−1 range, LOD value of 180 nmol L−1. The current response vs. Lead (Pb) concentration in graph by amperometric method exhibited correlation coefficient of 0.9991 and sensitivity of 0.0035 µA nM−1. The fabricated iminephthalocyanine based sensor is stable, reproducible and free of interference from other metal ion impurities in the electrolyte. The designed sensor has been employed for practical application.

Investigation of cryogenic mixed-refrigerant cooled current leads in combination with peltier elements

Current leads supply electrical energy from a room-temperature power supply to a superconducting application, representing thus a major thermal load. State-of-the-art cooling solutions use either open (vapor cooled) or multi-stage closed cycle systems. The multi-stage concept can be integrated in one cryogenic mixed refrigerant cycle (CMRC), where a wide-boiling fluid mixture absorbs the heat load continuously along the current lead. In this paper, we study the combination of CMRC cooling with Peltier elements at the warm end of DC current leads. The Peltier cooling may cause a temperature drop on the order of 80 K. This allows an optimization of the CMRC mixture composition towards lower temperatures, avoiding the use of high-boilers that risk to freeze out at low temperatures. Our studies suggest that Peltier and CMRC cooling can reduce the thermal load at the cold end by 30 to 45% compared to conventional conduction-cooled current leads.

Design and Performance Testing of a 1.2 kA Peltier Current Lead

Peltier current lead (PCL) is a device based on Seeback effects. PCL can reduce the leakage heat of the high-temperature superconducting (HTS) cable, which could improve the overall operating efficiency of the HTS cable. The numerical calculation and simulation analysis model of the PCL based on Bi2Te3 thermoelectric materials is established, and the optimized design method of PCL is obtained. Consequently, the design and manufacture of a kA-class PCL with 8 parallel connected Bi2Te3 thermoelectric elements is completed. The experimental results show that the maximum current deviation of the PCL under different transmission currents is less than 5 A, and the maximum temperature difference is less than 10 K, which is consistent with the designed value. At the same time, the heat leakage is approximately 32 W/kA at the rated current of 1200 A, which is about 25% lower than conventional copper current leads.

Helium Transfer Line with Conduction-Cooled Nb-Ti Superconducting Wires for COMET Muon Transport Solenoid

Cryogenic system of the superconducting magnet for COMET (COherent Muon to Electron Transition) experiments has been constructed in the J-PARC since FY2013. The cryogenic system can be roughly divided into superconducting magnet, refrigerator system and inter-connect system. The refrigeration system is composed of cold box and warm screw compressor system which are located on the surface. On the contrary, magnet system will be installed in the underground. Therefore the inter-connect system is mainly composed of current lead box and transfer line, which are regarded as a system for connecting between ground facility and the underground superconducting system. Since the superconducting magnet is cooled by two-phase flow helium at around 4.5 K, the transfer line has an adiabatic structure with shield line of around 50 K. In addition, conduction cooled superconducting cables are laid in parallel with the two-phase flow cooling line. In this study, simulation on the pressure drop of gas-liquid two-phase flow of helium is introduced to determine the cooling pipe diameters in the transfer line. Then the detail structures of the transfer line and cooling scheme of the superconducting cables optimized by several experiments will be presented.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

Where are we at with lead? Current levels, time trend, and determinants of blood lead in New Zealand children and adults.

A national biomonitoring survey was conducted in 2014-2016, to determine current blood lead levels (BLL) in New Zealand children and adults and identify determinants of BLL. Blood samples were provided by 191 children (age 5-18) and 304 adults (age 20-65) and analysed for BLL using inductively coupled mass spectroscopy. Linear regression on log-transformed BLL was used to assess associations between BLL and demographic and lifestyle factors collected via questionnaire. The geometric mean (GM) BLL was 0.86μg/dl (95%CI 0.80-0.92) for children and 1.31μg/dl (1.23-1.39) for adults, representing a 90% reduction in BLL over the past 36 years. For children, shellfish consumption was associated with 20% higher BLL. Adult BLLs were positively associated with age, beer consumption, spirits consumption, having roof water as the home's water supply, and having worked in glass manufacturing. Determinants of reduced BLL were tofu and canned food consumption. For women, menopause was associated with 34% higher BLL. Although significant reductions in New Zealanders' BLL have been achieved in the past decades, this study identified several additional opportunities to reduce further background exposure to lead. In particular, consideration needs to be given to reducing lead levels in New Zealand roof water supplies.

Safety analysis of the 100 kA HTS current lead for CFETR

Based on the Agreement of Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) and Ministry of Science and Technology of China during the Thirteen Five-Years Plan (so called 13∙5 plan), a dedicated test facility of superconducting magnet for China Fusion Engineering Test Reactor (CFETR) will be constructed in Hefei, China. A pair of high temperature superconducting (HTS) current leads rated at 100 kA for the CFETR magnet test facility is being designed at ASIPP. Because magnetic energy stored in the toroidal field magnet is 134 Giga Joules which are 3 times higher than the ITER case, HTS current leads must work at nominal current without performance degradation during the HTS current lead quench. In order to verify the safety and reliability of HTS current lead, the analysis of static magnetic field is done by ANSYS iteration to predict the maximum current carrying capacity of HTS module. This paper also give the numerical calculation of loss of flow accident(LOFA) of HTS current lead and temperature margin analysis of HTS module. The analysis results indicate that the HTS module has a current carrying capacity of 165 kA without external field at 65 K and a current carrying capacity of 149 kA with external 30 mT vertical field at 65 K. The LOFA time is about 580 s and the burnout time is about 30 s, which is better than the requirement of the toroidal field coil fast discharge time of 24 s.

River suspended sediment load prediction based on river discharge information: application of newly developed data mining models

ABSTRACTSuspended sediment load (SSL) is one of the essential hydrological processes that affects river engineering sustainability. Sediment has a major influence on the operation of dams and reservoir capacity. This investigation is aimed at exploring a new version of machine learning models (i.e. data mining), including M5P, attribute selected classifier (AS M5P), M5Rule (M5R), and K Star (KS) models for SSL prediction at the Trenton meteorological station on the Delaware River, USA. Different input scenarios were examined based on the river flow discharge and sediment load database. The performance of the applied data mining models was evaluated using various statistical metrics and graphical presentation. Among the applied data mining models, the M5P model gave a superior prediction result. The current and one-day lead time river flow and sediment load were the influential predictors for one-day-ahead SSL prediction. Overall, the applied data mining models achieved excellent predictions of the SSL process.

Експериментальне дослідження частотного дискримінатора з компенсації зміни рівня вхідного сигналу

Subject and Purpose. Answering the need for powerful high-frequency signal generation and desired radar range provision, pulsed magnetrons hold the current lead as part of radar transmitters. Yet there are some disadvantages, such as significant noise level and technological difficulties concerning the frequency tuning implementation. In this connection, a direct control of the pulsed magnetron frequency with the use of the Automatic Frequency Control (AFC) causes problems. And in the receiver, the AFC of the heterodyne rather than of the magnetron is more frequently used. The heterodyne frequency is maintained at such a level that the receiver is always tuned to the frequency of signal to receive. For various signal generation arrangements, the existing methods of frequency tuning with a frequency discriminator will be analyzed towards the following development of a principal electrical schematic diagram with gaining the operating characteristics of the frequency discriminator prototype on that diagram basis. Methods and methodology. The electrical schematic diagram is developed in terms of intuitive approach and analyzed by the mathematical modeling method. Results. The functional scheme of a frequency discriminator combining advantages of both single-cycle circuit (design simplicity and ease of tuning) and two-cycle circuit (null output voltage at a given frequency of the input signal and compensation possibilities as to the input voltage amplitude varying and interference) has been developed. The principal electrical schematic diagram of this new frequency discriminator has been reported together with the measured amplitude and frequency characteristics, dynamical figures, etc. Conclusions. The novelty of the proposed concept of a heterodyne AFC system built around a frequency discriminator has been confirmed. Its advantages over the known solutions have been shown.

The influence of the welding circuit magnetic field on the formation of the joint at unsupported welding

ABSTRACT The influence of researches results of the welding circuit magnetic field on the seam formation at welding steel 12X18H10T by weight with a non-consumable electrode in argon are presented. The possibility of retaining the molten metal of the weld pool by the magnetic field of the current flowing along a rectilinear conductor located in the plane of the welded joint above the tail of the weld pool is shown. It is established that the efficiency of holding the molten metal of the weld pool is largely determined by the location of the current lead, the speed and rigidity of the welding mode.

Comparison of the Operating Conditions of Electric Arc Furnaces with Short and Long Arc Discharges

A mathematical model is developed to describe the electromagnetic energy transfer between the phases of an electric arc furnace. This model is used to study the efficiency of operation of a DSP-100 electric arc furnace with the coplanar arrangement of a secondary current lead for short, medium, and long arc discharges. The energy processes in the furnace are found to be determined by both the potential gradients in arc discharges and the electromagnetic coupling of the phases, which causes redistribution of the total power released in arc discharges between the phases. Recommendations for the application of a phase-by-phase controlled reactor during long-arc operation are made.