scholarly journals Optimizing operation of electrical fuse circuit with controllable overload current

2021 ◽  
Vol 2021 (2) ◽  
pp. 71-77
Author(s):  
Konstantin Aleksandrovich Klimkin

The article discusses the application of a rapid action electrical fuse with controllable overload current in the schemes of industrial and household electrical equipment. There has been found a deficiency in the basic version of the scheme. A variant of the circuit was proposed, which helps to get rid of the drawback in the basic version: if a condenser with relatively large capacity (C ≥ 100 μF) is present in the protected circuit (in the load circuit), the circuit may not reach the operating mode, because, when the condenser is on, its large charging current triggers the electronic fuse and the load remains unconnected. This situation can be avoided only if the charging current of the condenser is greatly reduced, for which a current source on a field-effect transistor VT3 and a timing circuit R10R11C1 were introduced into the circuit. As C1 is being charged, through the current source VT3 there is a smooth increase in the bias voltage at the emitter junctions of the composite transistor switch VT1VT2 with a gradual increase in its conductivity. As a result, the starting current through the capacitive load at the first moment of time turns out to be much less, and the electronic fuse enters the operating mode. The optimal relationships were found between individual elements of the circuit, their values and modes of operation, depending on the size and nature of the load, while, thanks to the use of the domestic element base, the cost of the device turned out to be minimal compared to other circuits of a similar type. The research data can be used for operation of the devices of a similar type in the household and for industrial applications.

2019 ◽  
Vol 290 ◽  
pp. 02007
Author(s):  
Radu Dan Paltan ◽  
Cristina Biriş ◽  
Loredana Anne-Marie Rădulescu

Of many techniques that are used to optimize production and costs, the studies conducted within a profile company lead to our choice for testing the 6Sigma method (the most used method in the automotive industry) in view of the economic efficiency applied in the wood Industry company. This method measures how many flaws exist in a process and determines in a systematic way how to improve it by technical overhauling and eliminating or minimizing the process for efficiency. This research article aims to study the state of research on the optimization of the production process through technical overhauling for panels reconstituted from solid wood and ways to make production more efficient by cutting costs through technical overhauling. From preliminary research, we estimate that all the items founded and others that will result from further research will result in a significant decrease in production costs that are reflected in the cost of the finished product and consequently in increasing the yield of the company by maximizing its profit. At the same time it may be the basis of future research studies in the field. The easier it is to maximize profits, the lower the operating costs are and the higher recovery rate of investments are, that will result a change in the operating mode: “working smarter not harder”.


Author(s):  
G A Parker ◽  
Y B Sun

The work presented in this paper deals mainly with a mechatronic approach to compact disc valve design and concentrates on improvements to the disc valve electromagnetic characteristics, the diaphragm design and the dynamic performance. A novel diaphragm-disc force motor has been successfully developed incorporating a pair of permanent ring magnets. It has the advantages of low electric power consumption at the null position, dual-lane electrical structure for fail-safe operation, high control accuracy and should be competitive with existing torque motors due to its low cost and simple construction. The research involved designing and testing a prototype disc pilot valve with a dual-lane operating mode. The test results showed that the valve has satisfactory static and dynamic characteristics for industrial applications.


2018 ◽  
Vol 36 (5) ◽  
pp. 435-447 ◽  
Author(s):  
Roshan Kuruvila ◽  
S. Thirumalai Kumaran ◽  
M. Adam Khan ◽  
M. Uthayakumar

AbstractThe efficiency of industry depends upon the working conditions of the equipment and components used in the industrial process. The biggest problems faced by the industries are the problems of erosion and corrosion. The harmful effects of corrosion will lead to material loss, which results from the degradation of the equipment. The degradation of the equipment will cause the breakdown of the plant; moreover, it is a threat to the safety of people, and also from the point of conservation, it can cause the exploitation of available resources. The cost of replacing equipment increases the expense, and it can also result in the temporary shutdown of the plant. The protection of surfaces from the adverse effects of corrosion and erosion-corrosion is a matter of great concern in most industrial applications. Advancements in technology provides a wide range of techniques to overcome adverse conditions. The selection of appropriate technology must be from the viewpoint of their interaction with the environment. This review paper addresses the adverse effects of erosion-corrosion in the present scenario.


Probably 80% of all testing performed in electrical power systems is related to the verification of insulation quality. This chapter briefly describes the fundamental concepts of insulation testing including – insulation behavior, types of tests, and some test procedures. Most electrical equipment in utility, industrial, and commercial power systems uses either 50 or 60 Hz alternating current. Because of this, the use of an alternating current source to test insulation would appear to be the logical choice. However, as will be described a little later, insulation systems are extremely capacitive. For this and other reasons, DC has found a large niche in the technology. Before we can really evaluate the value of one system as opposed to the other (e.g. AC vs DC), let us examine how each type of voltage affects insulation. Testing of underground power cables are reported by NS161. (2014). IEC 6038. (1979). IEC Standard 60228. (1979). IEC60229. (2007). IEC60230. (1974). IEC60233. (1981). IEC 60332 (1974). IEC 6071 (2008). IEC 60270. (2000), IEC 60287. (2002).


Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5621
Author(s):  
Vladimir Chishkala ◽  
Serhiy Lytovchenko ◽  
Bohdan Mazilin ◽  
Edwin Gevorkyan ◽  
Vladimir Shkuropatenko ◽  
...  

In the paper, a novel technique for highly dispersed pyrochlore Y2Ti2O7 is proposed. The experimental results proved that the application of microwave irradiation at a certain stage of calcination allowed synthesizing of Y2Ti2O7 in much shorter time, which ensured substantial energy savings. An increase up to 98 wt.% in the content of the preferred phase with a pyrochlore-type structure Y2Ti2O7 was obtained after 25 h of yttrium and titanium oxides calcination at a relatively low temperature of 1150 °C, while the microwave-supported process took only 9 h and provided 99 wt.% of pyrochlore. The proposed technology is suitable for industrial applications, enabling the fabrication of large industrial amounts of pyrochlore without solvent chemistry and high-energy mills. It reduced the cost of both equipment and energy and made the process more environmentally friendly. The particle size and morphology did not change significantly; therefore, the microwave-assisted method can fully replace the traditional one.


2020 ◽  
Vol 11 (2) ◽  
pp. 37 ◽  
Author(s):  
Daouda Mande ◽  
João Pedro Trovão ◽  
Minh Cao Ta

Power electronics play a fundamental role for electric transportation, renewable energy conversion and many other industrial applications. They have the ability to help achieve high efficiency and performance in power systems. However, traditional inverters such as voltage source and current source inverters present some limitations. Consequently, many research efforts have been focused on developing new power electronics converters suitable for many applications. Compared with the conventional two-stage inverter, Z-source inverter (ZSI) is a single-stage converter with lower design cost and high efficiency. It is a power electronics circuit of which the function is to convert DC input voltage to a symmetrical AC output voltage of desired magnitude and frequency. Recently, ZSIs have been widely used as a replacement for conventional two-stage inverters in the distributed generation systems. Several modifications have been carried out on ZSI to improve its performance and efficiency. This paper reviews the-state-of-art impedance source inverter main topologies and points out their applications for multisource electric vehicles. A concise review of main existing topologies is presented. The basic structural differences, advantages and limitations of each topology are illustrated. From this state-of-the-art review of impedance source inverters, the embedded quasi-Z-source inverter presents one of the promising architectures which can be used in multisource electric vehicles, with better performance and reliability. The utilization of this new topology will open the door to several development axes, with great impact on electric vehicles (EVs).


2018 ◽  
Vol 7 (4.15) ◽  
pp. 469
Author(s):  
Pakedam Lare ◽  
Byamakesh Nayak ◽  
Srikanta Dash ◽  
Jiban Ballav Sahu

The cascaded H-Bridge Multilevel Inverter has been found a promising technology in industrial applications because of its higher voltage with less distortion production. Various PWMs techniques have been proposed to push the harmonics frequencies higher than the switching frequency and thus reduces the THD as compared to non-carrier control technique based upon grid frequency. The Phase-Shifted PWM technique has an advantage over others PWM techniques because its harmonics orders are multiples of switching frequency and also depend on the number of levels of the inverter. The phase shifting angle is uniform when the equal voltage sources are adopted. However, in applications where sets of different voltage source levels feed the H-Bridge cells, the Phase Shifted PWM suffers its high order harmonics elimination capability. As a solution to alleviate this problem, an adaptive variable angle approach is proposed in this paper using Particle Swarm Optimization (PSO) algorithm to eliminate desired higher order harmonics. The algorithm is used to minimize the cost function based on high order sideband harmonics elimination equations. The results through MATLAB/Simulink environment shown in this paper confirm the reduction of sideband harmonics of higher orders, and the overall THD.  


Author(s):  
L Cammarata ◽  
A Fichera ◽  
A Pagano

Controlling the dynamics of natural circulation loops represents a major task for the widespread use of this kind of system in safe industrial applications. This paper aims to design an innovative model-based optimal controller for the suppression of unstable oscillations and flow reversals, which affect the dynamical behaviour of a closed-loop thermosyphon at high heating rate. The key idea is to define a multivariable control law aiming to minimize an objective function taking into account both the stability of the system and the cost of control. The design of the proposed controller has been based on a model approximating to the first three modes of the dynamics of rectangular circulation loops with imposed heat fluxes at the boundaries. The capability of the proposed controller in suppressing undesired dynamics has been experimentally demonstrated.


2020 ◽  
Vol 15 (1) ◽  
pp. 73-82
Author(s):  
A. V. Rudakova ◽  
E. A. Stadnik

Background. Currently, treatment of recurrent / refractory chronic lymphocytic leukemia (CLL) involves the appointment of regimens with innovative drugs, which include ibrutinib and a combination of venetoclax and rituximab. Wherein said combination provides continuing over time high frequency eradication of minimal residual disease. Thereby, this regimen can be canceled if patients do not progress after 2 years from therapy start.The objective of the study was to assess the pharmacoeconomic aspects of therapy with venetoclax and rituximab combination in patients with recurrent / refractory CLL compared with ibrutinib monotherapy.Materials and methods. Analysis was performed by a simulation method from a position of the health care system. In accordance with network meta-analysis results of clinical studies in the recurrent / refractory CLL treatment (MURANO for venetoclax + rituximab combination and RESONATE and HELIOS for ibrutinib), which showed the absence of statistically significant differences in progression-free and overall survival between these treatment options, the cost-minimization method was used in the analysis. In the basic version, the model time horizon is 4 years. The price of venetoclax, rituximab and ibrutinib in the calculation corresponded to that registered (for rituximab – the median of the registered prices) with the value-added tax and the weighted average wholesale allowance taking into account the population in Russia.When analyzing the healthcare system budget impact, the time horizon of the study was 4 years. Therapy with combination of venetoclax + rituximab starting from the first year was suggested in 100 % of newly identified recurrent / refractory CLL patients. In the base case, it was estimated that 100 patients would need therapy every year.In the basic version of analysis, the cost of therapy after progression was not taken into account. In sensitivity analysis, an option taking into account therapy cost after progression, suggesting the appointment of venetoclax in the ibrutinib group and ibrutinib in the venetoclax + rituximab group, was also evaluated. In addition, variants with disease progression were additionally evaluated in 15 % of patients per year in the venetoclax therapy group at the end of the 2-year treatment course, as well as with an increase and decrease in the disease progression rate by 15 % in both comparison groups.As part of the sensitivity analysis, an assessment is made of a 15 % decrease and increase in Venetoclax price, a 30 % decrease in Ibrutinib price compared to registered price and the option with a 3-year study time horizon. When analyzing the budget impact, options with an increase in the number of patients annually identified and requiring treatment by 10, 20, 30 and 50 % were evaluated. Clinical and economic analysis was carried out with a discount rate of 3.5 % per year. A budget impact analysis was performed without discounting.Results. According to the results of cost-effectiveness analysis in the basic version, a regimen including venetoclax can reduce costs by 46.3 % compared with ibrutinib (cost for 4 years per patient is 10.422 and 19.413 million rubles, respectively). Therapy with combination of venetoclax + rituximab in 100 newly identified recurrent / refractory CLL patients annually instead of ibrutinib monotherapy will result in a reduction in therapy costs by 29.0 %, or by 1.579 billion rubles for 4 years per 100 patients starting therapy annually. The sensitivity analysis demonstrated the high reliability of the results. Conclusion. The treatment of recurrent / refractory CLL with a combination of venetoclax and rituximab is comparable in clinical efficacy with ibrutinib monotherapy and can significantly reduce the cost of the healthcare system, and therefore increase the availability of innovative therapy for this group of patients.


2020 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Alistair J. Manning ◽  
Sunyoung Park ◽  
Kieran M. Stanley ◽  
...  

Abstract. We report a 40-year history of SF6 atmospheric mole fractions measured at the Advanced Global Atmospheric Gases Experiment (AGAGE) monitoring sites, combined with archived air samples to determine emission estimates from 1978–2018. Previously we reported a global emission rate of 7.3 ± 0.6 Gigagrams (Gg) yr−1 in 2008 and over the past decade emissions have continued to increase by about 24 % to 9.04 ± 0.35 Gg yr−1 in 2018. We show that changing patterns in SF6 consumption from developed (Kyoto Protocol Annex-1) to developing countries (non-Annex-1) and the rapid global expansion of the electric power industry, mainly in Asia, have increased the demand for SF6-insulated switchgear, circuit breakers and transformers. The large bank of SF6 sequestered in this electrical equipment provides a substantial source of emissions from maintenance, replacement and continuous leakage. Other emissive sources of SF6 occur from the magnesium, aluminium, electronics industries and more minor industrial applications. More recently, reported emissions, including those from electrical equipment and metal industries, primarily in the Annex-1 countries, have steadily declined through substitution of alternative blanketing gases and technological improvements in less emissive equipment and more efficient industrial practices. Conversely, in the non-Annex-1 countries SF6 emissions have increased due to an expansion in the growth of the electrical power, metal and electronics industries to support their development. There is an annual difference of 2.5–5 Gg yr−1 (1990–2018) between our modelled top-down emissions and the UNFCCC reported bottom-up emissions, which we attempt to reconcile through analysis of the potential contribution of emissions from the various industrial applications which use SF6. We also investigate regional emissions in East Asia (China, S. Korea) and Western Europe and their respective contributions to the global atmospheric SF6 inventory. On an average annual basis, our estimated emissions from the whole of China are approximately 10 times greater than emissions from Western Europe. In 2018, our modelled Chinese and Western European emissions accounted for ~ 36 % and 3.1 %, respectively, of our global SF6 emissions estimate.


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