Mains Supply Research Articles

Automatic Star Delta Starter with an Arduino and Relays for Three Phase Induction Motor

Abstract: The most popular low voltage starters for 50 Hz industrial motors are either star or delta starters. Their purpose is to minimize the starting current that is supplied to the motor at the beginning of operation. Three contactors, a timer, and a thermal overload are typically used in the manufacturing of Star/Delta starters, which are used to run three-phase motors at 440 volts and 50 Hz AC mains supply. But in our project, we've used the same to run a\ 3-phase motor at 440-volt AC mains supply 50 Hz with a series of 12-volt DC relays, an Arduino-provided electronically adjustable timer, and a series of tiny circuit breakers. While maintaining its application for a 3-phase motor starting with a single phasing prevention, the interlocking arrangement of the relay coils and the electronic Arduino is all wired in low voltage DC of 12 Volt fed from an inbuilt DC power supply for safe handling of the starter during the study. The timer consists of an Arduino, whose output is sent to a relay to switch the mains supply from a three-phase star to a delta. Since the 3-phase motors could burn if one of the phases disappears while they are operating, the project additionally includes single-phase protection. In the case of a phase failure, the lamps' output will be switched off. In addition, the project can be improved by utilizing thyristors in a firing angle control principle to soft start the induction motor, which would eliminate all of the star delta starter's shortcomings.

Conduction Heat Study of Different Coil Design of Electric Iron

Electric iron pulls energy from the mains supply and heats a coil within then the heat is transferred to the bottom plate through conduction process which is placed against the wrinkled garment. The problem of existing dry iron is the heating element continues to get hotter until the power source is continuously drawn from electricity, do not heat up sufficiently, needed a continual charge from its platform every few minutes for prolonged use, cannot be heat up rapidly and fast aging problem. Hence, it is necessary to run the finite element analysis on electric iron part model. The simulation focusses on thermal analysis as it can ease the study related to the heat path and thermal design of simulated product that can be used to improve the efficiency of existing product. The 3D part models of electric iron and five different type of heating coil were designed. Rheological data and important properties of the electric irons were imported as a parameter database in the software to create the meshing on the model. The input parameters are heat power, heat flux and convection while the variable for the simulation process are design of heating coil, power supply, thickness of heating coil and material of soleplate. Based on the simulated part model, the features recommended is design coil 4 with power supply 1900W, coil thickness 0.0015m and ceramic soleplate as these variables has highest temperature and shortest steady state time.

An Intelligent System with Multiple Power Supply Modes

A low-cost and intelligent power supply system with an STC15 single-chip microcomputer as the main controller is designed. The single chip monitors the mains voltage and controls the relay to switch between the mains and battery power supply. Battery constant current, constant voltage, and floating charge intelligent charging management are achieved through the battery voltage execution. Through the ESP8266WIFI module networking, we can access weather information, and weather judgment, and choose whether to enter the battery mode, which can better protect the power system. The experimental results show that the system can operate reliably and complete the switch between mains supply mode and battery supply mode quickly.

Analysis of Plasma Reactor Interaction with the Power Grid Depending on the Power Supply Design

In this paper, the collaboration of a GlidArc-type plasma reactor with four dedicated power supplies was analysed. Each power supply is characterised by a different design solution. Plasma generation by electrical discharge requires a careful analysis of the power supply design, its operating characteristics, currents, voltages and frequencies. Although the power supplies tested have similar abilities and provide similar power supply parameters, different plasma reactor performance characteristics are obtained for each of them. The results indicate that some power supply parameters were overestimated or underestimated at the design stage. Some of the power supplies tested under plasma reactor load also show poor interaction with the mains. The interaction of the power supplies with the plasma reactor and the mains supply is strongly influenced by the type of plasma gas. Analyses indicate that an optimally designed power supply should combine the solutions contained in each of the power supplies tested.

Operation of a Dc/3ϕ power converter using a single‐delta bridge‐cell converter under low magnetizing inductance

AbstractA single‐delta bridge‐cell converter (hereinafter referred to as an SDBC converter) is a prospective power converter for a static synchronous compensator (STATCOM). The authors have proposed a dc/3ϕ power converter using the SDBC converter and a medium‐frequency single‐phase transformer with an operating frequency of 150 Hz; this converter can exchange a maximum active power of 37% of the rated reactive power with three‐phase ac mains supply without increasing the voltage and current ratings of the SDBC converter. In particular, the negative‐sequence reactive power control is a challenging task because of the high magnetizing inductance of the transformer. To achieve the negative‐sequence reactive power control, a single‐phase transformer with low magnetizing inductance is applied to the converter at the expense of the exchangeable active and reactive power. The relationship of the magnetizing inductance, active power, and reactive power is revealed in this paper, and the operation of the converter under low magnetizing inductance is experimentally verified by employing a downscaled 110‐V, 7‐kVA model.

Forcing Power Supply of a Xenon Flash Lamp to Create a High Power Irradiation Facility

The article describes the technical characteristics of the software-controlled power supply system for generation of second-long light pulses by means of INP‑16/580 xenon flash lamps. The amplitude-time characteristics of luminous emission in a quasi-arc mode of lamp operation are formed by computer control of temporal current pulse shape in case of large energy deposition overloads. Methods of optimisation of light and engineering characteristics were defined accounting for non-linearity of the load of the thyristor unit and ambiguity of the dependence of luminous radiation on discharge current. The data on maximum acceptable operation parameters of pulse lamps with mains supply and natural air cooling and the results of physical modelling of radiation pulses with complex shape are presented.

Security Door Lock for Mains Supply and Safety of Electrical Engineer

The main motive of this work is to provide safety to the electrical field engineer who works on the site of main distribution line feeder box. To provide safety to the engineer, the feeder box is equipped with RFID sensor and RFID readers which plays an important role. The engineer will be provided authorized glows and shoes with RFID tags. The reader mounted on the box will check whether the glows are authorized or not. If it gets authorized, then only the main door of the box will open and engineer will do his work. When the door gets opened it will share the details to the main server of the electrical distribution office in the form of message “The door is open”. We have made the provision that it will help engineer to solve the issue after door opens. There will be one-way communication from distribution office to electrical field engineer regrading guidelines for the issues. We have also made an application to record the history of the problems in the data base which would help to identify problems in the future.

INCREASING THE ENERGY PARAMETERS OF THE MAINS SUPPLY BY ACTIVE RECTIFIERS IN THE COMPOSITION OF FREQUENCY CONVERTERS

The total power consumed by electrical loads from the electric mains consists of their two components – active and reactive. Most electric drives of modern industrial enterprises operate with a reactive power index of 0.7–0.8. This leads to increased consumption of full power, which increases the load on the mains supply. Modern electric drives are built according to the principle: power supply – rectifier – DC link-inverter – asynchronous motor. Full power consumption occurs at the junction of the “power supply-rectifier”, where the required active power factor of the converter device can be formed. The higher the active power factor, the lower the reactive component in the total energy consumed. Thus, the article proposes a solution to the problem of creating highly efficient converter devices for powering electric motors with the formation of the necessary power factor, since frequency-controlled electric drives of modern mechanisms in industrial enterprises are the main consumers of electricity, which have a significant impact on the state of the supply network. The article considers the possibility of increasing the power factor of the mains input of electric drives with two-link frequency converters based on active (controlled) rectifiers with current inverters and voltage inverters. New methods of control of active rectifiers based on the use of AC rectifiers on fully controlled thyristors GTO, GCT, as well as IGBT transistors with pulse width adjustment are proposed. The variants of the construction of these rectifiers and the results of modeling the proposed control methods are presented, confirming a decrease in the passive components of the mains current, and as a consequence, an increase in the power factor of the network input. The simulation results are performed in the MATLAB 10 program, and are the basis for confirming the method of increasing the active power factor at the network input of a controlled frequency converter with a two-link structure.

Design and Analysis of an Automatic Power Changeover with Backup

The stability of the power supply in Ghana and another part of Africa is a major concern to the community and shop owners. The need for alternative power supply support and switching of load between two power sources. The system will eliminate the need for manual intervention by sensing the main gridline supply and switching to a backup source. Automation charger over to the backup source will eliminate the delay and provide efficiency in production. The system will automatically switch back when main gridline power is restored back. the system uses a microcontroller as the main automatic changing over the process and other component consists of a power supply circuit consisting of a step-down transformer, rectifier, filter capacitor, voltage regulator, and sg3525 which perform the oscillation convention from DC to AC Renewable energy sources generating direct current will require inverters to produce the alternating current necessary for domestic and industrial use The design, construction, testing of this circuit, is satisfactorily in switching from mains supply to generator/renewable energy source(s) and vice versa.

Design and Implementation of an Automatic Over/Undervoltage Protection System for Single-Phase Low Voltage Power Lines

Today, many industrial and domestic electronic appliances and equipment (devices) are exposed to power disturbances such as voltage variations of the AC mains supply which often lead to damage of the electronic devices. As these devices are quite sensitive to power disturbances, there is a need for a tripping system that can help avoid any damage to devices in use. The objective of this work is to build a system that monitors line voltage and protects appliances from unacceptable voltage variations. The system consists of a tripping mechanism that monitors the input voltage and trips according to the limits provided. An Arduino Uno microcontroller is used to determine the voltage level through a voltage divider circuit. The system’s novelty and innovation lie in its flexibility. It offers the user the ability to define different overvoltage and undervoltage threshold values depending on the specific appliances used in the household. In operation, the system displays the voltage state (overvoltage, normal voltage, overvoltage) and alerts the user by sending an SMS via a GSM modem. The system is valuable for industrial and domestic applications, especially in developing economies such as those of Sub-Saharan Africa, where overvoltage and undervoltage are acute problems.

Accelerating and Mitigating Postharvest Losses in Nigeria Through an Automated Hydrid Dryer

Africa has the world's biggest population of people without access to electricity, with an estimated 600 million people without access today and 700 million by 2030. Currently, almost two-thirds of Nigeria's population lacks access to reliable energy, and the majority of rural regions are not connected to the national grid. Given these staggering statistics, farmers in Nigeria, especially those in the production section are exposed to postharvest losses annually. Every year, Nigeria loses N3. 5 trillion in post-harvest losses due to a lack of suitable storage facilities and bad road conditions across the country. To mitigate this trend and help accelerate the adoption and acceptability of technology that will solve these postharvest problems, a hybrid dryer is developed. This research involved the development of an automated passive, hybrid dryer developed in the Federal Polytechnic Auchi, Edo State Nigeria with a research grant from TETFUND. A detailed AUTOCAD model for the dryer is developed and validated through experimentation. Energy and environmental analysis of the proposed dryer system were equally evaluated. Two crop produce, yam and tomatoes were used in evaluating the machine. One of the major highlights of the machine is that it is an automated dryer with power sources from both solar and mains supply. The drying process was conducted during the day, and it was compared with open sun drying and oven drying. The highest solar drying temperature obtained under the same condition for both yam and tomatoes were 38 0 C. At the average solar radiation of 2462 W/m 2 and air flow rate of 19.74 kg/s, the thermal efficiency of the hybrid dryer was obtained at 23.74 %. It was observed that the thermal efficiency of the collector was high when compared to similar dryers from literatures. Further analysis to established the commercial scalability of the system is however, recommend. Keywords: Postharvest losses, Hydrid, Automated, Accelerate, Mitigate DOI: 10.7176/ISDE/12-4-02 Publication date: October 31 st 2021

New EV Battery Charger PFC Rectifier Front-End Allowing Full Power Delivery in 3-Phase and 1-Phase Operation

A new universal front-end PFC rectifier topology of a battery charger for Electric Vehicles (EVs) is proposed, which allows fast charging at rated and/or full power level in case of 3-phase (Europe) as well as 1-phase (USA) mains supply. In this regard, a conventional 3-phase PFC rectifier would facilitate only one-third of the rated power in case of 1-phase operation. The new topology is based on a two-level six-switch (2LB6) 3-phase boost-type PFC rectifier, which is extended with a diode bridge-leg and additional windings of the Common-Mode (CM) chokes of the EMI filter. Besides this extension of the power circuit, the general design of the new converter is explained, and the generated Differential Mode (DM) and Common Mode (CM) EMI disturbances are investigated for 3-phase and 1-phase operation, resulting in guidelines for the EMI filter design. The EMI performance (CISPR 11 class-B QP) is experimentally verified for 1-phase and 3-phase operation at an output power of 4.5 kW, using a full-scale hardware prototype that implements the proposed extensions for a 2LB6 3-phase boost-type PFC rectifier and that is designed for output power levels of 22 kW and 19 kW in case of 3-phase and 1-phase operation, respectively. Compared to a conventional 2LB6 PFC rectifier, the volume of the extended system increases from 2.7 dm3 to 3.4 dm3, of which 0.5 dm3 is due to the additional dc-link capacitance for buffering the power pulsation with twice the mains frequency occurring for 1-phase operation.

PUMA – An open‐source 3D‐printed direct vision microscope with augmented reality and spatial light modulator functions

3D-printed microscopes are a topical emerging field in the literature. However most microscopes presented to date are quite novel re-imaginings of the microscope's mechanical design and they are either solely dependent on, or primarily geared towards, camera-based observations rather than ergonomic direct vision screening through an ocular lens. The reliance on camera, computer and monitor for observation introduces a compromise between portability, cost and the quality of an instant wide field of view. In this report, I introduce the Portable Upgradeable Modular and Affordable (PUMA) microscope which is an open-source 3D-printed multimodality microscope that employs a traditional upright design for ease of human direct visual observations and slide screening. PUMA uses standard RMS or C-mount objectives, with a tube length 160 mm, 170 mm or infinity and wide field high eye point ocular lenses. PUMA can use simple mirror-based illumination or can be configured to a full Köhler system with Abbe condenser for high numerical aperture observations including oil immersion. PUMA also has advanced digital/optical imaging features such as a digital spatial light modulator and - unique to any 3D printed microscope to date - an augmented reality heads-up display for interactive calibrated measurements. Digital camera imaging can also be used with PUMA - in fact PUMA can take up to three separate digital cameras simultaneously. PUMA can also function as a direct vision multi-header microscope for teaching or discussion. The illumination system is also modular and includes transillumination, epi-illumination, fluorescence, polarisation, dark ground and also Schlieren-based phase contrast and other Fourier optics filtering modalities. All these advanced features are available through an on-board, battery operated, microprocessor so no mains supply, smartphone, network connection, PC or external monitor are required making PUMA a truly portable system suitable for remote field work.

Detecting Power Grid Synchronization Failure on Sensing Frequency or Voltage Beyond Acceptable Range

This main objective of this paper is to build a simulation model of a system ,in proteus software ,which monitors voltage and provides a breakpoint by low and high voltage tripping mechanism that keep away from any damage to the load, Majority of industrial and domestic systems would encounter fluctuation in the AC mains supply. The chance of damaging electronic devices is very big as they are quite sensitive to these fluctuations. So, Tripping system that avoids any damage to these loads is necessary. This system has tripping mechanism that monitors the input voltage and trips according to limits provides. The system delivers an error as soon as the input voltage falls out of the window range. This system is also configured with an alarm that goes on as soon as tripping takes place.we use mainly microcontroller, comparator and led display for detection of over/under voltage and frequency and we also use GSM to send notification in web terminal.

Dynamic Simulation of High-Speed Induction Motor

In the drives of high-speed devices, such as a blood centrifuge, dynamic states also play an important role in terms of the time and quality of the tests performed. The article presents the application of modified equations resulting from the mathematical model of an induction motor to model dynamic phenomena during motor start-up, both with mains supply and with frequency start-up. The applied solution considers the phenomenon of current displacement in the rotor bar and the phenomenon of saturation. The comparison of the obtained results with the experiment shows that the method is sufficiently accurate. The obtained results can also be extended to higher power machines and to modeling other dynamic states.

Investigation of two cases of Mycobacterium chelonae infection in haemato-oncology patients using whole-genome sequencing and a potential link to the hospital water supply

Haemato-oncology patients are at increased risk of infection from atypical mycobacteria such as Mycobacterium chelonae which are commonly found in both domestic and hospital water systems. To describe the investigation and control measures following two patient cases of M.chelonae and positive water samples in the study hospital. Water testing was undertaken from outlets, storage tanks and mains supply. Whole-genome sequencing (WGS) was used to compare patient and positive water samples. The subsequent infection control measures implemented are described. The WGS results showed two main populations of M.chelonae within the group of sampled isolates. The results showed that the patient strains were unrelated to each other, but that the isolate from one patient was closely related to environmental samples from water outlets, supporting nosocomial acquisition. WGS was used to investigate two patient cases of M.chelonae and positive water samples from a hospital water supply. Relevant control measures and the potential for chemical dosing of water systems to enhance proliferation of atypical mycobacteria are discussed.

THE INFLUENCE OF THE INPUT INDUCTANCE ON THE QUALITATIVE INDICATORS OF ACTIVE CONTROLLED RECTIFIER

The main part of electricity is used by industrial plants in a converted form and the use of semiconductor converters is growing rapidly. The requirements for the quality of semiconductor converters are increased. And their impact on the power supply, load and related consumers is increased too. One of the most popular converters in the segment of low and medium power drives is a frequency converter made on the basis of a three-phase stand-alone voltage inverter. A significant disadvantage of such converters is the use of a diode rectifier at the input of the circuit, which has disadvantages as the inability to recover electricity to the mains in the mode of dynamic braking of an induction motor and significant distortions of the mains current. These disadvantages can be eliminated by using an active rectifier instead of a diode rectifier, which provides a sinusoidal shape of the mains current in phase with the mains voltage and the possibility of bidirectional energy exchange with the load. The efficiency of the active rectifier-voltage source is determined by the selected control algorithm of the circuit switches and the correct task of the inductance of the input choke. A mathematical model of a three-phase active rectifier-voltage source, working with a fixed modulation frequency with a vector algorithm for building a control system and analysis of the influence of the input inductance on the quality of its work was created. From the simulation results it became obvious that the proposed structure of the control system provides stable operation of the converter and acceptable standards for electromagnetic compatibility with the mains at a fixed modulation frequency; the proposed algorithm for calculating the value of the input inductances allows you to correctly select their allowable value, and obtained in the simulation of the dependence allows you to most accurately determine the value of the input inductances on the allowable level of distortion of mains current and supply voltage.

An environmental gamma spectrometry system with CsI(Tl) scintillator and FPGA based MCA for open field deployment

Inorganic scintillator-based gamma spectrometry is typically carried out under laboratory conditions by using systems that require AC mains supply and dedicated computers for their operation. In this study, an in-house grown CsI(Tl) single crystal scintillator is optically coupled to a bialkali photomultiplier tube (PMT). The output of the PMT is fed to a pulse processing chain consisting of a preamplifier followed by an in-house designed and developed field programmable gate array (FPGA) based multichannel analyzer (MCA). Spectral data from this MCA is sent via serial communication to a microcontroller. A global system for mobile communications (GSM) modem transmits this data in the form of short message service (SMS) packets to a central receiving station, where the spectrum is reconstructed. The requirement of on-site data logging computer to store large spectral data has thereby been eliminated, which, in turn, has eliminated the requirement of AC power supply, reduced the overall power consumption and size of the system, and made it possible to develop a standalone solar-powered unit. For further reduction of overall power consumption, the spectrometer is turned-on only when a Geiger Mueller (GM) counter based gross gamma detection circuit, also included in the system, detects an ambient gamma dose rate beyond a pre-set threshold level. A mathematical methodology has also been implemented for restoration of recorded spectra, shifted due to temperature variations in the environment. All these features have been integrated and a standalone, solar-powered and battery operated field-deployable environmental gamma spectrometry system (EGSS) has been developed and tested for open field deployment. Presence of 41Ar in ambient air was successfully detected by the system.

Расчет параметров схемы замещения индуктивно-кондуктивного нагревателя

To reduce production costs in the design and creation of an inductive-conductive heater (ICH), it is necessary to carry out a preliminary calculation as accurately as possible. This is possible when using the most approximate electrical circuit for replacing the ICH to a real object. It becomes possible to assess the work of the ICH in various operating conditions, including emergency conditions, using simpler modeling. An inductive-conductive heater transformertype is a three-rod W-shaped magnetic circuit with primary windings, which are covered by a heat exchanger (HE) of three concentric systems of electrically conductive cylinders with an internal slotted channel for the coolant. The energy from the mains supply is inductively transferred to the heat exchanger through the air gap by means of the primary winding. The secondary circuit of an electromagnetic device is a heat exchanger in which electrical energy is converted into heat. The heat flux from the heated cylindrical walls of the HE conductively heats the coolant circulating in the system to the required temperature. The large surface area of the HE allows you to avoid its overheating in relation to the coolant, which has a positive effect during the operation of the ICH in heating and hot water supply systems, significantly reducing the deposition of water impurities on the walls of the HE. The service life of the device is increased to 100 thousand hours or more. In the work, the synthesis of elements of the ICH equivalent circuit is carried out and the results of calculating the characteristics of the stationary mode of a number of products are presented. The equivalent circuit allows you to simulate electromagnetic processes in devices of different power, voltage and industrial frequencies in the range of 50…1000 Hz. If the configuration of the heating chamber (secondary circuit) is changed, the parameters of the elements of the equivalent circuit are adjusted without changing the general construction algorithm. For new products of inductive-conductive heating, there are no bibliographic data for calculating the elements of the equivalent circuit, especially regarding the formation of the replacement circuit of the secondary circuit, determined by the design of the heating chamber. To fill this gap, the authors have done this work.

Energy interaction of two-link converters of a multi-motor drive with mains supply

It is known that the total power electrical loads consume from the mains is the sum of their two components – active and reactive. Most electric drives of modern industrial enterprises consume up to 40% of reactive energy in relation to the total energy. This results in an increased full power consumption thereby increasing the load on the supply mains. Modern electric drives are built as follows: supply mains – rectifier-direct current link-inverter – asynchronous motor. The total power consumption is at the "mains-rectifier" interface, where the required active power factor of the converter can be formed. The higher the active power factor, the lower the reactive component in the total consumed energy. Thus, the paper proposes a solution to the problem of building highly efficient converting devices for powering electric motors with the required power factor. In particular, the paper discusses possible increase in the power factor of the electric drive mains input with two-link frequency converters based on active (controlled) rectifiers with current and voltage inverters. The author proposes new ways to control active rectifiers based on the use of AC rectifying devices with fully controlled GTO, GCT thyristors, as well as pulse-width control IGBT transistors. The paper offers options for the construction of these rectifiers and the results of modeling the proposed control methods, confirming a decrease in the passive components of the mains current, and, as a consequence, an increase in the mains input power factor. The simulation results were obtained in MathLab 10, and are the basis for confirming the method of increasing the active power factor at the mains input of a controlled two-link frequency converter.