Armature reaction
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Armature reaction is the effect of current flowing in the armature windings on the main field flux in a DC machine. It causes two undesirable effects: 1) a reduction in the main field flux per pole, and 2) distortion of the main field flux wave along the air gap. Armature current produces cross-flux that either aids or weakens the main flux depending on its location. This results in a non-uniform flux distribution and a shift in the magnetic neutral axis in the direction of rotation for a generator and against rotation for a motor. It also causes demagnetization due to magnetic saturation, further reducing the main field flux from its no-load value.
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Synchronous machines
Synchronous machines include generators and motors. Synchronous generators are the primary source of electrical energy and convert mechanical power to AC power. They rely on synchronous motors which are used for constant speed industrial drives. Synchronous generators have a rotor with DC excitation and a stator with a 3-phase winding. They come in salient-pole or cylindrical rotor types. Synchronous motors operate by synchronizing their rotor field to the rotating stator field to convert electric power to mechanical power. They are often used for large, low speed, high power applications like pumps and compressors.
Reduction methods of armature reaction in DC machines
Armature reaction is the effect of the magnetic field produced by current in the armature conductors on the main field produced by the generator's poles. This distorts the main field in two ways: by weakening it (demagnetization) and shifting it (cross-magnetization). Several methods are used to reduce the effects of armature reaction, including using laminated pole shoes, compensating windings, and ensuring a strong main field compared to the armature field.
Armature reaction
Armature reaction is the distortion of the magnetic field in a DC generator caused by the magnetic field produced by current in the armature. This reaction shifts the neutral plane and affects commutation. It can reduce the induced EMF and torque. Methods to reduce armature reaction include using poles with high reluctance at the tips, laminated pole shoes, reducing armature flux through field pole laminations, having a strong main magnetic field, using interpoles, and adding compensating windings.
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DC MOTORS-UNIT-II.pdf
- A DC motor converts electrical energy into mechanical energy through electromagnetic principles. It has a rotor that rotates when current passes through the motor's armature winding within a magnetic field.
- The key components of a DC motor are the armature winding, field winding, commutator, and brushes. The field winding generates a magnetic field and the armature winding cuts this field to produce torque when powered.
- DC motors can be shunt wound, series wound, or compound wound depending on how the field winding is connected in relation to the armature winding. This determines the speed and torque characteristics of the motor.
Armature windings
This document discusses different types of armature windings used in DC motors and generators including lap, wave, simplex, duplex, and triplex windings. It explains the characteristics of each type of winding such as the number of parallel paths through the armature, the relationship between back and front pitch, and how they are connected to the commutator segments. The document also covers closed winding configurations and how they provide multiple parallel paths while maintaining a zero resultant EMF around the complete armature circuit.
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Armature reaction is the effect of the magnetic field produced by current in the armature conductors on the main field produced by the generator's poles. This distorts the main field in two ways: by weakening it (demagnetization) and shifting it (cross-magnetization). Several methods are used to reduce the effects of armature reaction, including using laminated pole shoes, compensating windings, and ensuring a strong main field compared to the armature field.
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Armature reaction is the distortion of the magnetic field in a DC generator caused by the magnetic field produced by current in the armature. This reaction shifts the neutral plane and affects commutation. It can reduce the induced EMF and torque. Methods to reduce armature reaction include using poles with high reluctance at the tips, laminated pole shoes, reducing armature flux through field pole laminations, having a strong main magnetic field, using interpoles, and adding compensating windings.
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- A DC motor converts electrical energy into mechanical energy through electromagnetic principles. It has a rotor that rotates when current passes through the motor's armature winding within a magnetic field.
- The key components of a DC motor are the armature winding, field winding, commutator, and brushes. The field winding generates a magnetic field and the armature winding cuts this field to produce torque when powered.
- DC motors can be shunt wound, series wound, or compound wound depending on how the field winding is connected in relation to the armature winding. This determines the speed and torque characteristics of the motor.
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This document discusses different types of armature windings used in DC motors and generators including lap, wave, simplex, duplex, and triplex windings. It explains the characteristics of each type of winding such as the number of parallel paths through the armature, the relationship between back and front pitch, and how they are connected to the commutator segments. The document also covers closed winding configurations and how they provide multiple parallel paths while maintaining a zero resultant EMF around the complete armature circuit.
Synchronous motor
A synchronous motor is electrically identical with an alternator or AC generator.
A given alternator ( or synchronous machine) can be used as a motor, when driven electrically.
Some characteristic features of a synchronous motor are as follows:
1. It runs either at synchronous speed or not at all i.e. while running it maintains a constant speed. The only way to change its speed is to vary the supply frequency (because NS=120f/P).
2. It is not inherently self-starting. It has to be run up to synchronous (or near synchronous) speed by some means, before it can be synchronized to the supply.
3. It is capable of being operated under a wide range of power factors, both lagging and leading. Hence, it can be used for power correction purposes, in addition to supplying torque to drive loads.
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An induction motor is described with the following specifications:
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- Drawing 60A at 0.85 PF lagging
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- Magneto motive force (MMF) is the force that causes flux to flow, measured in ampere-turns. Reluctance is the opposition to flux flow, measured in ampere-turns/weber.
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A synchronous motor is electrically identical with an alternator or AC generator.
A given alternator ( or synchronous machine) can be used as a motor, when driven electrically.
Some characteristic features of a synchronous motor are as follows:
1. It runs either at synchronous speed or not at all i.e. while running it maintains a constant speed. The only way to change its speed is to vary the supply frequency (because NS=120f/P).
2. It is not inherently self-starting. It has to be run up to synchronous (or near synchronous) speed by some means, before it can be synchronized to the supply.
3. It is capable of being operated under a wide range of power factors, both lagging and leading. Hence, it can be used for power correction purposes, in addition to supplying torque to drive loads.
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- 480-V, 60 Hz, 50-hp, 3-phase
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Armature reaction in a DC machine is the effect of armature flux on the main field flux. It has two undesirable effects - it demagnetizes the main flux and distorts the main flux. This reduces generated voltage and torque and influences commutation limits. Methods to reduce armature reaction include compensating windings and interpoles, which produce fields opposing the armature flux effects.
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1) Synchronous machines have a rotor supplied by an external DC source that produces a rotating magnetic field. This induces a voltage in the stator windings.
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3) An equivalent circuit model represents the internal generated voltage and accounts for armature reaction, inductance, and resistance effects on the terminal voltage.
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- Magnet provides magnetic property, magnetic flux is the number of field lines passing through a closed surface.
- Magnetic flux density B and field intensity H are defined, with units of tesla and ampere/meter respectively.
- Magneto motive force (MMF) is the force that causes flux to flow, measured in ampere-turns. Reluctance is the opposition to flux flow, measured in ampere-turns/weber.
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The document describes the main construction of DC machines. It lists the two major parts as the stator, which houses the field winding, and the rotor, which rotates in the magnetic field. It then describes the other key parts which include the yoke, poles, field winding, armature winding, commutator, and brushes. The yoke forms a protective covering and carries magnetic flux. The poles contain core and shoe components that produce magnetic flux. The field and armature windings use copper wire to generate electromagnetism. The commutator collects alternating current from the armature and converts it to direct current, while the brushes collect this current.
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1. A transformer is a device that converts alternating current (AC) of one voltage to another voltage without changing the frequency. It consists of coils wrapped around a common core and uses electromagnetic induction.
2. Nikola Tesla proposed using transformers to increase voltage for efficient power transmission over long distances, then step it back down for safe distribution and use. This system replaced the inefficient direct current system developed by Edison.
3. Transformers allow efficient transmission of power by reducing current and thus transmission losses, while maintaining the same power level. They are essential components for modern power distribution systems.
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The document discusses V and inverted V curves of synchronous motors. V curves plot armature current against field current for constant load, showing how armature current varies with excitation. Inverted V curves plot power factor against field current. An experimental setup is described using a rheostat to vary excitation and two wattmeters to measure input power as field current is adjusted. The purpose of the curves is to analyze how armature current and power factor change with varying excitation of the synchronous motor.
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Torque Production & Control of Speed in Synchronous Motor.
Speed of synchronous motors can be controlled using two methods called open loop and close loop control.
Open loop contol is the simplest scalar control method where motor speed is controlled by independent frequency control of the converter.
In case of close loop self control mode, instead of controlling the inverter frequency independentaly, the frequency and the phase of the output waveform are controlled by an absolute position encoder mounted on the machine shaft giving an account of position of the rotor.
Speed control of dc motor
The document discusses speed control methods for DC motors. It explains that the speed of a DC motor is directly proportional to the back EMF and inversely proportional to flux. For shunt motors, speed can be controlled through flux control by adding resistance in the field winding, or through armature control by adding resistance in series with the armature. For series motors, speed is controlled through flux control using field or armature diverters or tapped field control, or through armature resistance control. Ward-Leonard control provides sensitive speed control for applications like elevators.
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An alternator is an electrical generator that converts mechanical energy to electrical energy. It uses a rotating magnetic field with a stationary armature. The working principle relies on Faraday's law of electromagnetic induction. As the armature rotates within the magnetic field, an alternating current is produced. The main components are the stator with stationary armature windings and the rotor with a rotating magnetic field supplied by a DC current. Armature reaction causes the magnetic field to be distorted by the armature current. Alternators have various applications including in automobiles, power plants, and for providing regenerative braking in induction motors. Induction generators can also be used to convert the rotational energy of windmills into electrical energy.
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This document provides information on DC machines, including their construction and operation principles. It describes how a DC machine can operate as either a motor or a generator. The rotor has coils wound in slots with ends connected to segments of a commutator. Brushes pressed against the commutator switch the current direction in the coils to maintain rotation. In a motor, the interaction between the magnetic field and current in the rotor coils produces a torque. In a generator, rotation of the coils in the magnetic field induces a voltage that is transmitted through the commutator.
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Similar to Armature reaction
Armature reaction
This document discusses armature reaction and commutation in DC machines. It defines armature reaction as the effect of armature magnetic flux on the main field flux produced by the stator poles. This causes the magnetic neutral axis to shift and the main flux to weaken. Commutation is defined as the process of reversing the current direction in armature coils as they pass from one pole to the next. Methods to improve commutation include using interpoles and adjusting brush position.
LOW CONVERSION LOSS DUAL GENERATOR
This paper explains losses associated with conventional generators due to armature reaction and self-induced emf and introduces a new design, dual generators, to scale down these losses. In the following paper, it will be shown how dual generators can offer better conversion of energy from mechanical to electrical and also reduce the above mentioned losses.
Armature reaction in a synchronous machine
1) Armature reaction is the effect of armature flux on the main field flux in a synchronous machine. When current flows in the armature windings, it produces an armature flux that interacts with the main field flux.
2) At unity power factor, the armature reaction flux lags the main field flux by 90 degrees. At zero lagging power factor, the armature reaction flux opposes and weakens the main field flux in a demagnetizing effect. At zero leading power factor, the armature reaction flux is in the direction of the main field flux and has a magnetizing effect.
3) The armature reaction flux remains constant in magnitude and rotates at synchronous speed.
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This document discusses DC generators and their components and operation. It describes:
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3) Issues that can occur with commutation in DC generators and different methods to improve commutation such as using resistance or interpole commutation.
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1) AC machines convert mechanical energy to electrical energy or vice versa. They operate based on simple principles, but real machines have complicated constructions.
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Notes on armature reaction in dc machines
Part of a lecture series delivered by me on DC machines to BE Third Year Students, Z. H. College of Engg. & Technology, AMU, Aligarh, 2012-13.
Please comment and feel free to ask anything related. Thanks!
Lec # 03 equivalent circuit of a synchronous generator
Lec # 03 equivalent circuit of a synchronous generatorMUET SZAB Campus Khairpur Mir's Sindh Pakistan
1) The internal generated voltage (EA) in a synchronous generator is different from the output voltage (Vφ) due to armature reaction, self-inductance, and resistance of the stator coils.
2) Armature reaction, caused by the distortion of the air-gap magnetic field by the stator current, is the largest effect. It can be modeled by an inductor in series with EA.
3) The full equivalent circuit model of a 3-phase synchronous generator includes a DC power source for the rotor field, and a per-phase equivalent circuit with EA in series with resistance and inductance to represent the combined effects of armature reaction and self-inductance.DC GENERATOR
Here are the answers to the questions on DC generator characteristics:
1. The external characteristic gives the relation between terminal voltage and load current.
2. The three most important characteristics or curves of a DC generator are: the no-load saturation characteristic (E0/If), internal or total characteristic (E/Ia), and external characteristic (V/I).
3. Critical speed of a shunt generator means the speed for which the given shunt field resistance represents critical resistance.
4. One condition necessary for the build-up of a self-excited shunt generator is that there must be some residual magnetism in the generator poles.
5. Some other factors which affect the voltage building of
Lect09 handout
1) The document summarizes key concepts from a physics lecture on magnetic forces and currents, including the right-hand rule.
2) Magnetic forces can act on both moving charges and on currents. A current-carrying loop placed in a magnetic field experiences both forces and torque.
3) The direction of the magnetic field generated by a long straight wire or solenoid is given by the right-hand rule. Using this rule, the magnetic interactions between two current-carrying wires or solenoids can be determined.
Lect09 handout
1) The document summarizes key concepts from a physics lecture on magnetic forces and currents, including the right-hand rule.
2) Magnetic forces can act on both moving charges and on currents. A current-carrying loop placed in a magnetic field experiences both forces and torque.
3) The direction of the magnetic field generated by a long straight wire or solenoid is given by the right-hand rule.
DC GENERATOR EE8301 Electrical Machines 1
Construction and components of DC Machine – Principle of operation – Lap and wave windings-EMF equations– circuit model – armature reaction –methods of excitationcommutation – interpoles compensating winding –characteristics of DC generators.
Electronic Measurement - Power Factor Meter
This article speaks about electrical power factor and how it can be measured using power factor meter
understandingtransformervectorgroup-180629014651.pptx
1) The document discusses transformer vector groups, which indicate the winding configurations and phase angle differences between primary and secondary windings.
2) For a Yd1 transformer, the secondary voltage leads the primary voltage by 30 degrees. However, if the terminal markings are changed, the vector group can change (e.g. to Yd5).
3) For positive sequence currents in a Yd1 transformer, the secondary currents lead the primary currents by 30 degrees. But for negative sequence currents, the secondary currents lag the primary currents by 30 degrees.
Armature Reaction
This presentation contains animative understanding of Armature reaction,compensating winding and interpoles
Understanding transformer vector group
This document discusses transformer vector groups and the phase shift between primary and secondary currents. It begins by introducing transformer basics like magnetically coupled circuits and phase relationships between voltages. Diagrams show how polarity markings and connections determine the vector group. Specific examples analyze the Yd1 and Yd11 vector groups in detail, showing how primary and secondary phase currents are related for both positive and negative sequence components. Tables summarize the results, and shortcuts are provided for identifying the vector group from winding configurations.
Answer MET Question 24.pdf
The back emf is an induced voltage in the armature of a DC motor that opposes the applied voltage according to Lenz's Law. The magnitude of the back emf can be calculated using the formula provided, and is always less than the applied voltage. The relationship between the applied voltage, back emf, armature current, and armature resistance is V = Eb + IaRa, where V is the applied voltage, Eb is the back emf, Ia is the armature current, and Ra is the armature resistance.
Ch28 ssm
The document contains a multi-part conceptual physics problem about magnetic induction.
Part 1 asks about orienting a sheet of paper at the magnetic equator to maximize or minimize magnetic flux through it. Part 2 shows that the units T⋅m2/s are equivalent to volts. Part 3 asks about the direction of induced current in a conducting loop based on the direction and changing magnitude of an applied magnetic field.
Final Project
This document describes the design of a three-stage operational amplifier with the following specifications: a voltage gain of 10,000 V/V, a 3dB frequency of 1MHz, a power supply of 9V or less, and an output resistance of less than 1kΩ. The design process involved simulating different transistor configurations and parameters to optimize the gain of each stage. The maximum gain achieved in simulation was 79.38dB at 1MHz, meeting the design goals. Calculations of various parameters generally agreed with simulation results, though some discrepancies remained.
Chapter 5 electromagnetism
The document discusses electric and magnetic fields, including:
- An electric field is established between two parallel metal plates charged to different potentials.
- Magnetic field lines originate and terminate on magnetic poles. Unlike poles attract while like poles repel.
- Electromagnetic induction occurs when a changing magnetic field induces an electric current in a conductor. The direction of the induced current opposes the change according to Lenz's law.
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Lec # 03 equivalent circuit of a synchronous generator
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CIRCUIT BREAKERS
INTRODUCTION
Types of Circuit breakers
CIRCUIT BREAKER RATINGS
OPERATING MECHANISM
CONCLUSION
Types of instruments
This document describes different types of instruments used for measurement of electrical quantities including permanent magnet moving coil instruments, moving iron instruments, electrodynamic instruments, hot-wire instruments, thermocouple instruments, induction-type instruments, electrostatic instruments, and rectifier-type instruments. It provides details on the working principles, advantages, disadvantages and applications of these instruments.
ELECTRICAL AND ELECTRONICS MEASUREMENT
This document discusses measurement techniques and instruments. It covers the basic components, classifications, functions, and errors of measurement instruments. The key points are:
- Measurement instruments have components for deflection, control, and damping of the pointer. Deflection indicates the measured quantity, control opposes deflection, and damping reduces oscillations.
- Instruments can be classified as analog or digital, absolute or secondary. Accuracy depends on design, materials, and errors like systematic, random, and environmental errors.
- Measurements involve comparing an unknown quantity to a standard and expressing the result numerically. Direct comparison is used when possible, otherwise indirect methods are used. Proper standards and methods are required for meaningful results.
NUCLEAR POWER PLANT
Nuclear power plants generate electricity through nuclear fission reactions in a controlled nuclear reactor. The first commercial nuclear power plant began operation in 1954. The document outlines the key components of a nuclear power plant including the nuclear fuel, nuclear fission and chain reactions, nuclear reactor, control rods, steam generators, turbines, pumps, condensers, and cooling towers. It also discusses both the advantages of low carbon emissions but the challenges of high costs, safety issues, and long-term radioactive waste disposal.
Thermal Power Station
The document describes the basic principles and components of a coal-fired thermal power plant. The key components include the boiler, turbine, generator, condenser, and cooling tower. Coal is burned in the boiler to produce high-pressure steam. The steam powers the turbine, which turns the generator to produce electricity. After passing through the turbine, the steam enters the condenser where it is cooled and condensed back into water, which is pumped back to the boiler to repeat the process.
Hydroelectric Power Plant
This document discusses hydroelectric power plants. It explains that hydropower works by using the kinetic energy of flowing water to turn turbines which spin generators to produce electricity. It describes different sizes of hydropower plants from pico to large, and types of turbines like Pelton, Francis and Kaplan. Governors are also summarized as maintaining a constant generator speed and frequency during fluctuations in electrical loads. Advantages include constant power production, water storage, and no greenhouse gas emissions. Disadvantages include high construction costs, environmental impacts, and potential international disputes over shared rivers.
Tips for better life
The document provides tips for living a better life in 2017. It suggests taking daily walks while smiling, sitting in silence for 10 minutes, sleeping 7 hours, living with energy, enthusiasm and empathy, playing games, reading more books, drinking water, eating more natural foods and less processed foods, spending time with both the young and old, forgiving others, and focusing on positivity. It encourages letting go of negativity, not taking yourself too seriously, making peace with the past, focusing on present happiness, agreeing to disagree, not comparing yourself to others, and giving to others daily.
Transformers
A transformer transfers electrical energy from one circuit to another through magnetic fields without changing frequency. It has a primary winding that receives energy and a secondary winding that transfers energy to the load. Transformers can increase or decrease voltage/current, match impedances for power transfer, and isolate circuits. There are core and shell types that differ in how windings are arranged around the core. Transformers work on electromagnetic induction - an alternating current in the primary induces a voltage in the secondary through an alternating magnetic flux in the core.
Starting methods Of DC Machines
This document discusses direct current (DC) motors and motor starters. It explains that DC motors draw a large starting current that can cause issues. Motor starters are used to gradually introduce voltage to reduce this starting current. The document then describes the components and operation of 3-point and 4-point motor starters, including how they introduce resistance to reduce starting current and use hold-on coils and overcurrent releases for protection. A 4-point starter is preferable when wide speed control is needed since its hold-on coil is independent of the field circuit.
Speed control Of DC Machines
The document discusses three methods for controlling the speed of a DC motor: 1) varying the armature circuit resistance, 2) varying the field flux, and 3) varying the terminal voltage using the Ward-Leonard method. It provides details on how each method works, including equations showing how speed is affected. The Ward-Leonard method uses a motor-generator set to convert AC power to DC power at a controlled voltage to regulate motor speed. Advantages and disadvantages of each method are also summarized.
Commutation in DC Machines
Commutation is the process by which the current in a short circuited coil is reversed as it crosses the MNA. During commutation, the coil is briefly short-circuited. If current reversal from positive to zero to negative is completed by the end of the short circuit period, commutation is ideal. If not completed, sparking can occur in the brushes, making commutation non-ideal. Commutation is illustrated through figures showing the current in a coil decreasing to zero and then reversing as it transitions from one side of the brush to the other during the short circuit period.
World wide web
The document discusses the history and development of the World Wide Web. It begins by explaining how the early Internet only allowed viewing of plain text screens but companies like AOL and CompuServe began developing ideas to change the layout and visual experience. The World Wide Web was then created, allowing for hyperlinked documents with multimedia like images and sounds. It also standardized the URL and made the WWW technology free to access, launching the Internet era of search engines, e-commerce, and more. The document then explores some key components and functions of how the World Wide Web works.
MODERN FORMS OF COMMUNICATION
The document discusses modern forms of communication like fax and the internet. It describes how a fax machine works by connecting to a phone line through a modem and transmitting copies of printed images. It also explains some advantages and limitations of using fax, such as the ability to quickly exchange information but the lack of confidentiality. The document then provides a brief introduction to browsing and searching the world wide web on the internet.
Analog and Digital Multimeters
This document discusses analog and digital multimeters. It describes two main types of multimeters: analog VOMs that use a moving coil meter with a printed scale, and digital multimeters that provide a numerical readout. Key aspects covered include how various meters work (voltmeters use high resistance multipliers, ammeters must be in series, ohmmeters use an internal battery), applications of each type of meter, and considerations for measuring voltage, current and resistance accurately. Loading effects on circuits are also addressed.
BLOGS AND SOCIAL NETWORKING
Blogs are personal online diaries or journals that are frequently updated, often daily. They contain the author's views, observations, analysis, and favorite links. Social networking services allow people to connect and share interests through online profiles and social links. Popular social networking sites in India include Facebook, Twitter, Orkut, and LinkedIn. While social networking provides low-cost connections and can build credibility, it also lacks anonymity and carries risks of scams, harassment, and being time consuming.
SIGNIFICANCE OF BLOCK DIAGRAM AND SIGNAL FLOW GRAPH IN CONTROL SYSTEM
This document discusses block diagrams and signal flow graphs, which are useful tools for modeling control systems. It begins by explaining what block diagrams are and how they represent the components and signal flows in a system. Signal flow graphs are then introduced as a more compact way to determine the relationships between input and output variables using Mason's gain formula, without needing to reduce the diagram. The document provides examples of block diagram reductions and simple signal flow graphs. It concludes that block diagrams and signal flow graphs provide control engineers a better understanding of systems by describing the connections between components.
Electrical Machines Notes 3 (Mechanical Work Done in a Singly excited system ...
1) The document discusses mechanical work done in singly and doubly excited magnetic systems.
2) In a singly excited system, mechanical work done equals the reduction in magnetic energy stored. In a doubly excited system, torque depends on instantaneous currents and rate of change of inductance.
3) The generated EMF in a machine is derived. The flux linkage of a coil moving in a "B-wave" is calculated, showing that the induced EMF is proportional to the rate of change of flux linkage.
Electrical Machines Notes 2 (Singly Excited Magnetic System) by Dr. P.S. Bimbhra
This document discusses the derivation of expressions for electrical energy input, magnetic energy stored, and mechanical work done in a singly excited magnetic system. It defines key terms like flux linkage, magnetic flux, and co-energy. It shows that the electrical energy input is equal to the change in magnetic field energy when no mechanical work is done. It derives an expression for the magnetic field energy stored in the magnetic circuit when a flux is established, and explains this is equal to the co-energy in the linear, non-saturated case.
Basic Concept of Rotating Electrical Machines by Dr. P.S. Bimbhra
This document discusses the basic concept of rotating electrical machines and the principle of electro-mechanical energy conversion. It explains that in energy conversion devices, the total input energy is partially converted to the required output form, some is stored, and the rest is dissipated. It also describes the various forms of energy involved, including total electrical input, mechanical output, energy stored in magnetic fields and mechanical systems, and energy dissipated via losses. Key equations show that the total electrical input energy minus losses equals the sum of the mechanical output energy, stored energy, and coupling losses.
CAPACITORS
Capacitors are geometries that can hold charges.
Use Gauss’ Law symmetries to calculate capacitance.
Series and parallel connections.
Dielectrics increase capacitance.
More from Dinesh Sharma (20)
SIGNIFICANCE OF BLOCK DIAGRAM AND SIGNAL FLOW GRAPH IN CONTROL SYSTEM
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Electrical Machines Notes 3 (Mechanical Work Done in a Singly excited system ...
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Electrical Machines Notes 2 (Singly Excited Magnetic System) by Dr. P.S. Bimbhra
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A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Adaptive synchronous sliding control for a robot manipulator based on neural ...
Robot manipulators have become important equipment in production lines, medical fields, and transportation. Improving the quality of trajectory tracking for
robot hands is always an attractive topic in the research community. This is a
challenging problem because robot manipulators are complex nonlinear systems
and are often subject to fluctuations in loads and external disturbances. This
article proposes an adaptive synchronous sliding control scheme to improve trajectory tracking performance for a robot manipulator. The proposed controller
ensures that the positions of the joints track the desired trajectory, synchronize
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errors and synchronous sliding surfaces are presented. Second, the synchronous
tracking error dynamics are determined. Third, a robust adaptive control law is
designed,the unknown components of the model are estimated online by the neural network, and the parameters of the switching elements are selected by fuzzy
logic. The built algorithm ensures that the tracking and approximation errors
are ultimately uniformly bounded (UUB). Finally, the effectiveness of the constructed algorithm is demonstrated through simulation and experimental results.
Simulation and experimental results show that the proposed controller is effective with small synchronous tracking errors, and the chattering phenomenon is
significantly reduced.
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Armature reaction
- 1. What is Armature Reaction?? Armature reaction is the effect of armature produced flux on the main field flux. The armature mmf produces two undesirable effects on the main field flux and these are:- 1) Net reduction in the main field flux per pole. 2)Distortion of the main field flux wave along the air- gap periphery.
- 2. How it takes place?? From the fig(A) it shows that the flux path for the main poles of a 2-pole DC machine at no load ie. With no armature currents. This main field flux, produced by GNA field mmf If Nf , is shown by horizontal MNA Phasor OA= . O A fΦ fΦ
- 3. Now when the DC machine is loaded, current flows in the armature windings. These currents are as shown in the figure (B), these currents set up armature flux shown by the vertical flux lines, with the field winding unexcited. The other figure represent armature flux Φa by a vertical phasor OB. GNA O B aΦ
- 4. Now by examination of the above two figures reveals that the path of armature flux Φa is perpendicular to the main flux path Φf . In other words, the path of the armature flux crosses the path of the main field flux. O A B Thus the effect of armature flux on the main field flux is entirely ‘cross-magnetizing’ and it is for this reason that the flux produced by armature mmf is called cross-flux. fΦ aΦ
- 5. Now when the current flows in both the armature and field windings, the resultant flux distribution is obtained by superimposing the two fluxes of fig (A) and fig(B).
- 6. From the fig(C)shown below, it is seen that the armature flux aids the main field flux at the lower end of the N-pole and at the upper end of the S-pole, therefore at these two poles, the armature flux strengthens the main field flux. GNA MNA Likewise, the armature flux weakens the main field flux at Upper end of the N-pole and at lower end of the S-pole. fΦ aΦ RΦ θ
- 7. Now, if there is no magnetic saturation, then the amount of strengthening and weakening of the main field flux are equal and the resultant flux per pole remains unaltered from its no load value. Actually, the magnetic saturation does occurs and as a consequence, the strengthening effect is less as compared to the weakening effect and the resultant flux is decreased from its no-load value. This is called ‘Demagnetizing effect of armature reaction’
- 8. Conclusion It may therefore be stated from the above that net effect of armature flux on the main field flux is:- 1) To distort the main field flux thereby causing non-uniform distribution of flux under the main poles. 2)To shift the MNA in the direction of the rotation for a generator and against the direction of rotation for a motor. 3)To reduce the main field flux from its no-load value due to magnetic saturation.