motor drive trouble shooting and diagnosis with Fluke ScopeMeter by checking unbalance of voltage and current, overvoltage and undervoltage, variable torque and constant torque, motor shaft voltage and bearing voltage
Reactive power compensation manages reactive power to improve AC power system performance related to load and voltage support. Reactive power compensation devices reduce reactive power flow in grids, lowering energy losses and improving operating conditions. Static VAR compensators (SVCs) are commonly used for reactive power compensation using thyristor-controlled reactors and capacitors to generate or absorb reactive power and regulate voltage. SVCs improve power transmission capability, transient stability, and load power factors to reduce losses and increase system capacity.
This document discusses power factor and harmonics. It defines power factor as the measurement between the current and voltage waveforms, and explains that power factor consists of working power (KW), apparent power (KVA), and reactive power (KVAR). Industries commonly known to have poor power factors include steel mills, chemical plants, and automotive assembly. Loads that cause power factor problems include induction motors, arc furnaces, and variable frequency drives. Improving power factor lowers electrical costs, increases capacity, and provides other benefits. Power factor correction capacitors are an economical way to improve power factor. The document provides guidance on determining required capacitance and installing capacitors.
1) Reactive power (Q) in an AC system represents power that is transferred back and forth between the source and load, rather than producing work.
2) Adding capacitors near an inductive load can compensate for the load's reactive power (QL) by providing an opposing reactive power (QC) , reducing voltage drops and power losses on the transmission line.
3) Increasing the level of compensation (QC) improves the system's power factor and increases its capacity to serve additional real power loads (ΔSC).
An Optimal Power Flow (OPF) Method withImproved Voltage Stability AnalysisNiraj Solanki
This document discusses an optimal power flow method with improved voltage stability analysis. It introduces voltage stability and instability concepts. It then describes a voltage stability indicator L derived from fundamental circuit laws that can predict proximity to voltage collapse. The document outlines the formulation of an optimal power flow problem to minimize generation costs and indicator L. It applies this method to the 9-bus WSCC test system in MATLAB and concludes the indicator can accurately predict voltage stability problems and vulnerable locations.
Optimal Location of Statcom for Power Flow ControlIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
This document discusses power factor correction and automatic power factor correction (APFC) systems. It explains that power factor is the ratio of active power to apparent power and can be lagging or leading. Low power factors are caused by inductive loads and non-linear loads. APFC systems use capacitors in automatic steps controlled by a microprocessor to maintain a high power factor under varying loads without manual intervention or risk of overvoltage. This improves efficiency and reduces utility penalties and equipment loading and sizes. The document provides specifications for capacitor selection and switching equipment for APFC systems.
Objectives: This course will provide a comprehensive overview of power system stability and control problems. This includes the basic concepts, physical aspects of the phenomena, methods of analysis, the integration of MATLAB and SINULINK in the analysis of power system .
Course Content: 1. Power System Stability: Introduction
2. Stability Analysis: Swing Equation
3. Models for Stability Studies
4. Steady State Stability
5. Transient Stability
6. Multimachine Transient Stability
7. Power System Control: Introduction
8. Load Frequency Control
9. Automatic generation Control
10. Reactive Power Control
This document discusses power factor correction and automatic power factor correction (APFC) units. It defines power factor and different types of circuits. It explains the importance and disadvantages of low power factor. It describes how APFC units use capacitor banks controlled by a regulator to automatically adjust the power factor above a desired level. The document outlines the key parts of an APFC unit and maintenance procedures.
Reactive power compensation manages reactive power to improve AC power system performance related to load and voltage support. Reactive power compensation devices reduce reactive power flow in grids, lowering energy losses and improving operating conditions. Static VAR compensators (SVCs) are commonly used for reactive power compensation using thyristor-controlled reactors and capacitors to generate or absorb reactive power and regulate voltage. SVCs improve power transmission capability, transient stability, and load power factors to reduce losses and increase system capacity.
This document discusses power factor and harmonics. It defines power factor as the measurement between the current and voltage waveforms, and explains that power factor consists of working power (KW), apparent power (KVA), and reactive power (KVAR). Industries commonly known to have poor power factors include steel mills, chemical plants, and automotive assembly. Loads that cause power factor problems include induction motors, arc furnaces, and variable frequency drives. Improving power factor lowers electrical costs, increases capacity, and provides other benefits. Power factor correction capacitors are an economical way to improve power factor. The document provides guidance on determining required capacitance and installing capacitors.
1) Reactive power (Q) in an AC system represents power that is transferred back and forth between the source and load, rather than producing work.
2) Adding capacitors near an inductive load can compensate for the load's reactive power (QL) by providing an opposing reactive power (QC) , reducing voltage drops and power losses on the transmission line.
3) Increasing the level of compensation (QC) improves the system's power factor and increases its capacity to serve additional real power loads (ΔSC).
An Optimal Power Flow (OPF) Method withImproved Voltage Stability AnalysisNiraj Solanki
This document discusses an optimal power flow method with improved voltage stability analysis. It introduces voltage stability and instability concepts. It then describes a voltage stability indicator L derived from fundamental circuit laws that can predict proximity to voltage collapse. The document outlines the formulation of an optimal power flow problem to minimize generation costs and indicator L. It applies this method to the 9-bus WSCC test system in MATLAB and concludes the indicator can accurately predict voltage stability problems and vulnerable locations.
Optimal Location of Statcom for Power Flow ControlIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
This document discusses power factor correction and automatic power factor correction (APFC) systems. It explains that power factor is the ratio of active power to apparent power and can be lagging or leading. Low power factors are caused by inductive loads and non-linear loads. APFC systems use capacitors in automatic steps controlled by a microprocessor to maintain a high power factor under varying loads without manual intervention or risk of overvoltage. This improves efficiency and reduces utility penalties and equipment loading and sizes. The document provides specifications for capacitor selection and switching equipment for APFC systems.
Objectives: This course will provide a comprehensive overview of power system stability and control problems. This includes the basic concepts, physical aspects of the phenomena, methods of analysis, the integration of MATLAB and SINULINK in the analysis of power system .
Course Content: 1. Power System Stability: Introduction
2. Stability Analysis: Swing Equation
3. Models for Stability Studies
4. Steady State Stability
5. Transient Stability
6. Multimachine Transient Stability
7. Power System Control: Introduction
8. Load Frequency Control
9. Automatic generation Control
10. Reactive Power Control
This document discusses power factor correction and automatic power factor correction (APFC) units. It defines power factor and different types of circuits. It explains the importance and disadvantages of low power factor. It describes how APFC units use capacitor banks controlled by a regulator to automatically adjust the power factor above a desired level. The document outlines the key parts of an APFC unit and maintenance procedures.
This document discusses analyzing unbalanced distribution systems using index vector approach. It aims to find optimal sizes and locations of capacitors under different loading conditions and types of unbalances. The analysis is performed on a 25-bus unbalanced radial distribution system. Results show that under unbalanced conditions, optimal capacitor allocation reduces losses and improves voltage profiles compared to the system without capacitors. The type and degree of unbalance impacts optimal capacitor sizing and placement.
The document discusses power system stability, including classifications of stability (steady state, transient, and dynamic) and factors that affect transient stability. It also covers topics like the swing equation, equal area criterion, critical clearing angle, and multi-machine stability studies. Some key points:
1) Power system stability refers to a system's ability to return to normal operating conditions after disturbances like faults or load changes.
2) Transient stability depends on factors like fault duration and location, generator inertia, and pre-fault loading conditions.
3) The equal area criterion states that a system will remain stable if the accelerating and decelerating area segments on the power-angle curve are equal.
4)
This document discusses various methods of reactive power compensation including shunt compensation using shunt reactors and capacitors, series compensation using series reactors and capacitors, static VAR compensators (SVCs) which use thyristor-controlled reactors and capacitor banks to regulate voltage, and synchronous condensers which are synchronous machines that can generate or absorb reactive power by varying excitation current to control reactive power flow. The purpose of reactive power compensation is to improve power factor, regulate voltage, eliminate current harmonics, and increase transmission capacity.
The document discusses automatic power factor controllers (APFC). It defines power factor and explains how inductive loads can cause low power factors. An APFC automatically switches capacitors to improve the power factor as loads vary. This reduces electricity bills, demand charges, losses, and improves voltage regulation. APFC panels ranging from 10 to 300kVar are presented along with their benefits like cost savings, better equipment performance, and reduced infrastructure needs. APFCs are recommended for various industrial and commercial applications.
The document discusses swing equation, which is used to model rotor dynamics in power systems. It defines swing equation as a second order differential equation that relates the change in rotor angle over time to the difference between mechanical and electrical power inputs. The document outlines the derivation of swing equation from the torque-speed relationship of a synchronous generator. It also discusses swing curves, which plot electrical power output versus rotor angle, and the equal area criteria method for assessing transient stability using swing curve plots.
1. A document discusses fault analysis in power systems, including symmetrical and unsymmetrical faults. Common fault causes include insulation failure, mechanical issues, over/under voltage, and accidents.
2. Key concepts are introduced, such as different types of reactance (subtransient, transient, steady-state) and how fault current transients have both AC and DC components.
3. Two examples are provided to demonstrate how to calculate fault current and MVA for given systems using per unit calculations and reactance values.
IRJET- Design a Fuzzy Distance Relay Including STATCOM EffectsIRJET Journal
This document discusses how the presence of a STATic synchronous COMpensator (STATCOM) can negatively impact the performance of a distance relay used to protect transmission lines. The authors use MATLAB/PSAT to model a sample power system with a transmission line protected by a distance relay. They simulate faults on the line with and without a STATCOM present and observe how the STATCOM causes issues like under-reach and over-reach for the relay. To address this, they propose designing a new fuzzy logic-based distance relay that accounts for the effects of STATCOM compensation to more accurately detect faults.
The document provides an introduction to power system analysis. It discusses the components of a power system including generators, transformers, transmission lines and loads. It explains that power system analysis involves monitoring the system through load flow analysis, short circuit analysis and stability analysis in order to maintain the system safely and economically. It also discusses the need for power system analysis in planning and operating the system, and ensuring power demand is met through reliable generation and transmission of electricity.
This document discusses power factor correction and automatic power factor correction (APFC) systems. It explains that power factor is the ratio of active power to apparent power and can be lagging or leading. Low power factors are caused by inductive loads and non-linear loads. APFC systems use capacitors in automatic steps controlled by a microprocessor to maintain a high power factor under varying loads without manual intervention or risk of overvoltage. This improves efficiency and reduces utility penalties and equipment loading and sizes. The document provides specifications for capacitor selection and switching equipment for APFC systems.
Implementation of Instantaneous Reactive Power Theory for Current Harmonic Re...IOSR Journals
This document discusses implementing the instantaneous reactive power theory (IRP theory) for current harmonic reduction and reactive power compensation in a three phase four wire power system. The IRP theory defines instantaneous power components in the α-β-0 coordinate system. It can calculate the reference compensating currents required by a shunt active power filter to inject into the network. Simulations show the power filter can reduce current harmonics and reactive power, improving the power factor by making the source current sinusoidal and in phase with the voltage. The IRP theory provides a flexible way to select the undesirable power components for compensation to minimize pollution from nonlinear loads.
This document discusses power factor and methods for improving it. It defines power factor as the ratio of active power to apparent power. Low power factor is caused by inductive devices and indicates inefficient electricity use. Correcting power factor through capacitors can provide benefits like increased plant capacity and reduced utility charges. Capacitors work by opposing inductive lagging current. They can be installed at individual equipment, equipment groups, or at the main service, with various tradeoffs to consider. Harmonic distortion from devices like variable speed drives can also impact power quality if not properly addressed.
The document presents a study on optimizing the placement and sizing of static VAR compensators (SVCs) in power systems to improve voltage stability. It uses the harmony search algorithm (HSA) to determine the optimal SVC sizes and locations to minimize real power losses, voltage deviation at load buses, and L-index values, which indicate voltage stability. The methodology is demonstrated on the IEEE 14-bus test system under normal and overloading conditions. The results show that locating optimally sized SVCs at buses 9 and 14 reduces losses and voltage deviations while improving voltage profiles and stability.
Power factor is the ratio of active power to apparent power. Low power factors are caused by inductive loads and non-linear loads which result in inefficient energy use and overloading of electrical equipment. Automatic power factor correction (APFC) systems automatically switch capacitor banks to maintain a target power factor under varying loads without manual intervention. Proper selection of capacitors, switching equipment, and harmonic filters is required when implementing APFC to prevent overloading and resonance issues.
The document discusses using a Static Var Compensator (SVC) to increase voltage stability and power limits on a transmission network in Venezuela. It analyzes placing a SVC at the "Malena" bus to:
1) Increase power flow through overhead transmission lines after a three-phase fault at the "Guri" bus, allowing over 48% more power while maintaining voltages between 0.8-1.2 p.u.
2) Maintain voltage levels during transient states like faults and load increases to prevent voltage collapse.
3) The SVC consists of a Thyristor Controlled Reactor (TCR) and fixed capacitors that can generate or absorb reactive power quickly to control voltage
Reactive power compensation using statcomAmit Meena
This document describes a study on reactive power compensation using STATCOM conducted by students under the guidance of Dr. Supriyo Das. It provides background on reactive power and the need for reactive power compensation. It then describes Static Synchronous Compensators (STATCOM) and includes the simulation diagram and output of a voltage source converter used in STATCOM. The conclusion discusses designing a VSC using PWM to inject compensated reactive power into the main power line and future work on improving the design.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document provides an overview of a seminar on power factor improvement using microcontrollers. It discusses key topics like what power factor is, causes of low power factor, automatic power factor correction using hardware components like a microcontroller, voltage regulator, power supply, relay, LCD display, and capacitor bank. The document outlines the advantages of power factor correction like reduced transformer rating, line losses, and equipment size. It concludes that using microcontrollers for automatic power factor correction makes power systems more stable and efficient while reducing costs compared to manual correction.
- The document discusses techniques for determining the load and efficiency of electric motors, which are large consumers of electricity in many operations. Knowing the motor load is important for identifying opportunities to improve efficiency.
- Key techniques discussed include measuring motor input power, line current, and operating speed to calculate load as a percentage of the motor's rated capacity. Understanding load is necessary to evaluate whether a motor is properly sized or a candidate for replacement with a more efficient model.
- Load measurements should be recorded and motors categorized as oversized/underloaded, moderately oversized, or properly sized but standard efficiency to prioritize replacement options for improving energy efficiency.
A tutorial document describes how to analyze symmetrical faults on a power system with three interconnected generators rated at 40 MVA, 50 MVA, and 25 MVA. It shows the system's configuration in a diagram and explains that the first step is to calculate the Thevenin's equivalent circuit seen from the fault location. The document then poses a problem - to estimate the maximum MVA that can be fed into a symmetrical short circuit occurring at the end of a feeder supplied by generator A, given the feeder impedances and generator ratings/configurations.
1. This document provides information about DC motors, including their principle of operation, production of back EMF, torque equation, classification, characteristics, applications, starters, speed control, losses and efficiency testing methods like brake test and Swinburne test.
2. It discusses different types of DC motors like shunt, series, compound motors and their speed-current, torque-current and speed-torque characteristics.
3. Methods of speed control like armature resistance control and field flux control are also explained. Starters and their working including three-point and four-point starters are described.
This document discusses analyzing unbalanced distribution systems using index vector approach. It aims to find optimal sizes and locations of capacitors under different loading conditions and types of unbalances. The analysis is performed on a 25-bus unbalanced radial distribution system. Results show that under unbalanced conditions, optimal capacitor allocation reduces losses and improves voltage profiles compared to the system without capacitors. The type and degree of unbalance impacts optimal capacitor sizing and placement.
The document discusses power system stability, including classifications of stability (steady state, transient, and dynamic) and factors that affect transient stability. It also covers topics like the swing equation, equal area criterion, critical clearing angle, and multi-machine stability studies. Some key points:
1) Power system stability refers to a system's ability to return to normal operating conditions after disturbances like faults or load changes.
2) Transient stability depends on factors like fault duration and location, generator inertia, and pre-fault loading conditions.
3) The equal area criterion states that a system will remain stable if the accelerating and decelerating area segments on the power-angle curve are equal.
4)
This document discusses various methods of reactive power compensation including shunt compensation using shunt reactors and capacitors, series compensation using series reactors and capacitors, static VAR compensators (SVCs) which use thyristor-controlled reactors and capacitor banks to regulate voltage, and synchronous condensers which are synchronous machines that can generate or absorb reactive power by varying excitation current to control reactive power flow. The purpose of reactive power compensation is to improve power factor, regulate voltage, eliminate current harmonics, and increase transmission capacity.
The document discusses automatic power factor controllers (APFC). It defines power factor and explains how inductive loads can cause low power factors. An APFC automatically switches capacitors to improve the power factor as loads vary. This reduces electricity bills, demand charges, losses, and improves voltage regulation. APFC panels ranging from 10 to 300kVar are presented along with their benefits like cost savings, better equipment performance, and reduced infrastructure needs. APFCs are recommended for various industrial and commercial applications.
The document discusses swing equation, which is used to model rotor dynamics in power systems. It defines swing equation as a second order differential equation that relates the change in rotor angle over time to the difference between mechanical and electrical power inputs. The document outlines the derivation of swing equation from the torque-speed relationship of a synchronous generator. It also discusses swing curves, which plot electrical power output versus rotor angle, and the equal area criteria method for assessing transient stability using swing curve plots.
1. A document discusses fault analysis in power systems, including symmetrical and unsymmetrical faults. Common fault causes include insulation failure, mechanical issues, over/under voltage, and accidents.
2. Key concepts are introduced, such as different types of reactance (subtransient, transient, steady-state) and how fault current transients have both AC and DC components.
3. Two examples are provided to demonstrate how to calculate fault current and MVA for given systems using per unit calculations and reactance values.
IRJET- Design a Fuzzy Distance Relay Including STATCOM EffectsIRJET Journal
This document discusses how the presence of a STATic synchronous COMpensator (STATCOM) can negatively impact the performance of a distance relay used to protect transmission lines. The authors use MATLAB/PSAT to model a sample power system with a transmission line protected by a distance relay. They simulate faults on the line with and without a STATCOM present and observe how the STATCOM causes issues like under-reach and over-reach for the relay. To address this, they propose designing a new fuzzy logic-based distance relay that accounts for the effects of STATCOM compensation to more accurately detect faults.
The document provides an introduction to power system analysis. It discusses the components of a power system including generators, transformers, transmission lines and loads. It explains that power system analysis involves monitoring the system through load flow analysis, short circuit analysis and stability analysis in order to maintain the system safely and economically. It also discusses the need for power system analysis in planning and operating the system, and ensuring power demand is met through reliable generation and transmission of electricity.
This document discusses power factor correction and automatic power factor correction (APFC) systems. It explains that power factor is the ratio of active power to apparent power and can be lagging or leading. Low power factors are caused by inductive loads and non-linear loads. APFC systems use capacitors in automatic steps controlled by a microprocessor to maintain a high power factor under varying loads without manual intervention or risk of overvoltage. This improves efficiency and reduces utility penalties and equipment loading and sizes. The document provides specifications for capacitor selection and switching equipment for APFC systems.
Implementation of Instantaneous Reactive Power Theory for Current Harmonic Re...IOSR Journals
This document discusses implementing the instantaneous reactive power theory (IRP theory) for current harmonic reduction and reactive power compensation in a three phase four wire power system. The IRP theory defines instantaneous power components in the α-β-0 coordinate system. It can calculate the reference compensating currents required by a shunt active power filter to inject into the network. Simulations show the power filter can reduce current harmonics and reactive power, improving the power factor by making the source current sinusoidal and in phase with the voltage. The IRP theory provides a flexible way to select the undesirable power components for compensation to minimize pollution from nonlinear loads.
This document discusses power factor and methods for improving it. It defines power factor as the ratio of active power to apparent power. Low power factor is caused by inductive devices and indicates inefficient electricity use. Correcting power factor through capacitors can provide benefits like increased plant capacity and reduced utility charges. Capacitors work by opposing inductive lagging current. They can be installed at individual equipment, equipment groups, or at the main service, with various tradeoffs to consider. Harmonic distortion from devices like variable speed drives can also impact power quality if not properly addressed.
The document presents a study on optimizing the placement and sizing of static VAR compensators (SVCs) in power systems to improve voltage stability. It uses the harmony search algorithm (HSA) to determine the optimal SVC sizes and locations to minimize real power losses, voltage deviation at load buses, and L-index values, which indicate voltage stability. The methodology is demonstrated on the IEEE 14-bus test system under normal and overloading conditions. The results show that locating optimally sized SVCs at buses 9 and 14 reduces losses and voltage deviations while improving voltage profiles and stability.
Power factor is the ratio of active power to apparent power. Low power factors are caused by inductive loads and non-linear loads which result in inefficient energy use and overloading of electrical equipment. Automatic power factor correction (APFC) systems automatically switch capacitor banks to maintain a target power factor under varying loads without manual intervention. Proper selection of capacitors, switching equipment, and harmonic filters is required when implementing APFC to prevent overloading and resonance issues.
The document discusses using a Static Var Compensator (SVC) to increase voltage stability and power limits on a transmission network in Venezuela. It analyzes placing a SVC at the "Malena" bus to:
1) Increase power flow through overhead transmission lines after a three-phase fault at the "Guri" bus, allowing over 48% more power while maintaining voltages between 0.8-1.2 p.u.
2) Maintain voltage levels during transient states like faults and load increases to prevent voltage collapse.
3) The SVC consists of a Thyristor Controlled Reactor (TCR) and fixed capacitors that can generate or absorb reactive power quickly to control voltage
Reactive power compensation using statcomAmit Meena
This document describes a study on reactive power compensation using STATCOM conducted by students under the guidance of Dr. Supriyo Das. It provides background on reactive power and the need for reactive power compensation. It then describes Static Synchronous Compensators (STATCOM) and includes the simulation diagram and output of a voltage source converter used in STATCOM. The conclusion discusses designing a VSC using PWM to inject compensated reactive power into the main power line and future work on improving the design.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document provides an overview of a seminar on power factor improvement using microcontrollers. It discusses key topics like what power factor is, causes of low power factor, automatic power factor correction using hardware components like a microcontroller, voltage regulator, power supply, relay, LCD display, and capacitor bank. The document outlines the advantages of power factor correction like reduced transformer rating, line losses, and equipment size. It concludes that using microcontrollers for automatic power factor correction makes power systems more stable and efficient while reducing costs compared to manual correction.
- The document discusses techniques for determining the load and efficiency of electric motors, which are large consumers of electricity in many operations. Knowing the motor load is important for identifying opportunities to improve efficiency.
- Key techniques discussed include measuring motor input power, line current, and operating speed to calculate load as a percentage of the motor's rated capacity. Understanding load is necessary to evaluate whether a motor is properly sized or a candidate for replacement with a more efficient model.
- Load measurements should be recorded and motors categorized as oversized/underloaded, moderately oversized, or properly sized but standard efficiency to prioritize replacement options for improving energy efficiency.
A tutorial document describes how to analyze symmetrical faults on a power system with three interconnected generators rated at 40 MVA, 50 MVA, and 25 MVA. It shows the system's configuration in a diagram and explains that the first step is to calculate the Thevenin's equivalent circuit seen from the fault location. The document then poses a problem - to estimate the maximum MVA that can be fed into a symmetrical short circuit occurring at the end of a feeder supplied by generator A, given the feeder impedances and generator ratings/configurations.
1. This document provides information about DC motors, including their principle of operation, production of back EMF, torque equation, classification, characteristics, applications, starters, speed control, losses and efficiency testing methods like brake test and Swinburne test.
2. It discusses different types of DC motors like shunt, series, compound motors and their speed-current, torque-current and speed-torque characteristics.
3. Methods of speed control like armature resistance control and field flux control are also explained. Starters and their working including three-point and four-point starters are described.
Paul Ryan was 28 years old when he ran for Congress in 1998 after Mark Neumann vacated the seat. Ryan shocked many by defeating his Democratic opponent Lydia Spottswood with 57% of the vote. Ryan's campaign was run by a small team including his brother and mother, and was focused on meeting with local leaders to gain endorsements. His campaign benefited from Spottswood releasing negative ads about Ryan early, while Ryan waited until closer to the election to debut an ad emphasizing his family ties to the district. Ryan's victory marked the beginning of his rise in politics from a young congressional candidate to a vice presidential nominee.
El documento describe la importancia del paquete Microsoft Office, que incluye aplicaciones como Word, Excel y PowerPoint. Estas aplicaciones permiten realizar tareas cotidianas como la redacción de documentos, cálculos y análisis de valores, y la elaboración de gráficos y dibujos, ahorrando tiempo y dinero. Office también ayuda a estudiantes y profesionales a organizar información y administrar investigaciones, y facilita la comunicación a través de Outlook.
The Indus Valley civilization flourished from around 3300 BC to 1300 BC along the Indus River valley in what is now Pakistan and northwest India, but many mysteries remain about this ancient society. Scholars have not determined the form of government or how the highly organized cities were managed. They have also not deciphered the writing system used by the Indus people or determined what religious beliefs they followed, as no temples have been found. The greatest mystery is what caused the decline and eventual disappearance of this civilization around 1500 BC, with theories including climate change, flooding, drought, earthquakes, foreign invaders, or economic problems depleting soil fertility and disrupting trade.
Ensuring food safety standards across all of your locations is an area of increasing concern. With multiple regulatory bodies focusing on the area due to recent high-profile foodborne illness outbreaks, it's also become an area of innovation.
In this presentation, we highlight:
- Food safety requirements and regulatory bodies
- Major areas of concern
- Trends in the industry
- How to prevent food safety disasters
Excel puede ser una herramienta útil para abogados al permitirles realizar contabilidad, presupuestos e informes que ayudan a administrar sus finanzas y operaciones comerciales, así como hacer un seguimiento de causas, facturas de clientes, y flujos de efectivo.
Este documento explora el origen etimológico y los conceptos objetivo y subjetivo de la economía. Explica que la palabra economía proviene del griego "oikonomos" que significa administración del hogar. Luego describe la definición objetiva marxista de la economía como la ciencia que estudia las relaciones sociales de producción, y la definición subjetiva marginalista como la ciencia que estudia la satisfacción de necesidades humanas con recursos escasos. Finalmente, resume las características principales de las corrientes objetiva
This document provides an overview of key sections of the Code of Civil Procedure. It summarizes the classes of civil courts in Bangladesh, defines important terms like decree and judgement debtor, and outlines sections related to jurisdiction of courts, res judicata, appeals, revisions, and execution of decrees. Specifically, it notes there are 5 classes of civil courts, defines elements of a decree, discusses limitations to filing execution within 12 years, and explains appellate courts have power to determine cases finally or remand them for trial.
This document discusses short-circuit calculations and selective coordination for electrical systems. It explains that short-circuit studies are required by the National Electrical Code to properly size overcurrent protection devices and ensure system coordination. The document provides guidance on calculating available short-circuit current values at different points in a system using the point-to-point method, which accounts for sources of fault current and impedances of system components. It also addresses variables that affect fault current values, such as transformer impedance, motor contribution, and utility voltage tolerance.
Bus ele tech_lib_short_circuit_current_calculations (1)ingcortez
LIBRO DE CALCULOS DE DATOS DE CORTO CIRCUITO ELÉCTRICO PARA CONDUCTORES DE COBRE Y ALUMINIO DEL TIPO MONOPOLARES O TRIFASICOS DENTRO DE CANALIZACIONES ELECTRICAS PLASTICAS O METALICAS EN VOLTAJES DE MEDIA Y BAJA TENSION CON FACTORES O CONSTANTES DE LOS CONDUCTORES ELECTRICOS EN METROS
By installing variable speed AC drives, you can improve process controls, increase energy savings, reduce wear on machinery, and improve power factor (PF). AC drives improve PF by circulating the motor's reactive current internally rather than sending it back to the power supply. This allows the drive's input current to be lower than the output current to the motor. For example, a drive might have an output current of 94.5A but only require an input current of 60A, reducing losses in the power system by 5%. While the primary benefits of drives are improved control and energy savings, higher PF is an added advantage that can save on utility penalties for low PF.
The document discusses designing a microcontroller-driven alternator voltage regulator. It begins by explaining the simplicity of older relay-based regulators and why microcontrollers are now used. A microcontroller allows for features like extended battery life, improved gas mileage, lower emissions, and flexibility. It then discusses some of the challenges in designing such a regulator, like controlling a current-mode machine (the alternator) by monitoring its voltage output. It describes the sensing, filtering, responding and regulation processes involved. Key aspects are a fixed-frequency regulation approach for stability, temperature compensation, and limiting the slew rate of field duty cycle changes to further improve stability.
COMPARATIVE STUDY OF INDUCTION MOTOR STARTERS USING MATLAB SIMULINKIJARIIT
This paper presents a comparison between the Direct-On-Line (D.O.L.), and Soft Starter by using MATLAB Simulink .The purpose of this project is to find out the theoretical and actual characteristics of Induction motor. These three basic starting methods which different the irrespective wiring connection are the most applicable and widely-used starting method in the industrial area due to its economic reasons. This project is done by analyzing the characteristics during the motor starting by using the MATLAB Simulation to capture the waveforms of these events. After the Simulation, the three different starting method are being compared to conclude the most suitable and applicable starting method.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
This document discusses techniques for determining the load and efficiency of electric motors in order to identify opportunities to improve efficiency through proper sizing or replacement of motors. Key points:
- Motor load and efficiency should be measured to identify if motors are oversized or underloaded.
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White Paper_Induction Motor Dynamics of Fast Bus Transfer_Rev0_26 Dec 2016Daniel Lang, P.Eng.
Daniel Lang, P.Eng. discusses various methods for supervised open transition bus transfer to maintain continuity of critical industrial loads during power source switching. There are two main categories of bus transfer - closed transition (parallel) and open transition. Open transition methods aim to minimize transient torque on induction motors during transfer by interrupting the original source before connecting the new source. Supervised open transition methods like fast, in-phase, and residual voltage transfers monitor conditions to safely reconnect motors before their terminal voltage and phase decay too much from the alternate source. Proper bus transfer supervision is needed to prevent catastrophic damage to motors from excessive transient torque during re-energization.
Permanent magnet motors like brushless DC (BLDC) motors have higher efficiency than induction motors due to using fixed magnets instead of induced currents for magnetization. BLDC motors are commonly driven with either trapezoidal or sinusoidal commutation. Trapezoidal commutation provides rougher torque but is simpler to implement, while sinusoidal commutation provides smoother torque without commutation noise. Field-oriented control allows maximum performance from permanent magnet synchronous motors like BLDC motors but requires position sensing or estimation.
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2) It recommends measuring voltage levels, sags, harmonics, unbalance, and currents over time at key points to track trends that may indicate degradation.
3) Catching issues early through low-cost power quality monitoring can help prevent nearly half of electrical failures according to industry studies and save on costs of downtime, repairs and replacement equipment.
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1. Application Note
Where do you start
when troubleshooting
problems?
In troubleshooting situations
involving a motor, more than
half the battle is simply isolat-
ing the problem. Whenever
there’s a working motor,
there’s a load and there’s some
sort of motor controller, which
is increasingly going to be an
adjustable speed drive (ASD).
So when problems arise, how
can you tell if it is the drive,
the motor, or the load? Here
are a few tips to tackle the
problem in a quick, systematic
way, making a few key meas-
urements as you go.
Imbalance measurements
A good place to start is with a
measurement of current drawn
by the motor. When we talk
about motors here, we are
referring to three-phase induc-
tion motors, the workhorse of
industry. Motors are balanced
loads: the current that they
draw on each phase should be
about the same (less than
ten percent, as measured
below). If they are not
balanced, the cause could be
internal to the motor (deterio-
rating stator insulation, for
example), or it could be the
result of voltage imbalance. So
if there is any problem with
current imbalance, make the
voltage imbalance measure-
ment (less than three percent)
at the output of the ASD. The
following calculation works
for either voltage or current
imbalance.
Voltage and current imbal-
ance measurements should also
be taken at the line side of the
drive. Drives are extremely
sensitive to voltage imbalance,
even more so than motors.
Drives are using the peak volt-
ages of each phase to charge
internal capacitor banks. If one
of these phases is even a bit
low, it will make it hard for the
drive to draw current from that
phase. So voltage imbalance
will cause current imbalance.
The drive may still function, but
the charge cycle of the capaci-
tors, and their ride-through
time in the event of voltage
sags, will be diminished.
In addition to imbalance
measurements, voltage drops
across loose connections
Is it the drive, the
motor, or the load?
F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y
Continued on next page
should also be checked. This
can be done with direct volt-
age measurements or with
infrared thermometers. Read-
ings that are much higher than
the ambient temperature, or that
are higher than other phases,
can indicate loose or otherwise
bad connections.
Percent imbalance = maximum deviation from average /
average of three phases X 100%
Example:
1. As measured: Phase A = 449 A; Phase B = 470 A;
Phase C = 462 A
2. Calculate Average = (449 + 470 + 462) / 3 = 460 A
3. Calculate Max Deviation = 460 – 449 = 11 A
4. Calculate Imbalance = (11 / 460) x 100 % = 2.4 %
Note: New three phase power quality analyzers perform these calculations automatically.
2. ASD overvoltage and
undervoltage trips
Drives have diagnostic codes
which identify the cause of
trip. Generally speaking, they
can be classified as overvolt-
age, undervoltage, or overload
(overcurrent). Note that
mechanical starters only have
overload trips. They’re not
concerned with over or under-
voltage. What makes drives
different?
Drives turn sine wave ac
into dc (converter section), and
then turn the dc back into ac
(inverter section). However, the
ac at the output is not a sine
wave. It is a special waveform
known as the pulse-width
modulated (PWM). The PWM,
from the motor’s point of view,
is accepted as if it were a sine
wave — almost (see Advanced
motor measurements below).
For now, though, let’s focus on
the drive internals, specifically
on what’s commonly referred
to as the dc link. The dc link is
nothing but a capacitor bank,
usually with a series link
inductor (reactor) thrown in for
filtering and protection. The dc
link is carefully monitored by
the drive; overvoltage or
undervoltage refers to the volt-
age of the dc link.
Undervoltage can be caused
externally by voltage sags on
the drive input. The Sags and
Swells function on Fluke power
quality analyzers can help to
identify line-related undervolt-
age problems. Problems could
also exist internally with the dc
link capacitors and/or reactor.
In many drives, there are test
points to measure the dc link
voltage. To check the capaci-
tors, use the min/max function
of a digital multimeter, or,
preferably, the trend function of
a Fluke power quality analyzer
or ScopeMeter®
test tool. Check
if voltage regulation is within
the manufacturer’s specifica-
tion. To check the reactor,
check the waveform on both
sides — there should be no
change.
When troubleshooting a
system, the tendency is to view
the drive or PLC as the most
susceptible to voltage sags. The
ice-cube control relay is most
often the source of sag-related
problems. Studies have shown
that these low-cost compo-
nents are the first to drop out
when voltage sags occur. So
don’t forget to look at any
external control circuit while
you’re troubleshooting intermit-
tent system shutdowns.
Overvoltage could be a
symptom of problems in the
capacitors or reactor. Or it could
be caused by line-related volt-
age transients. At one point,
utility capacitor switching tran-
sients were notorious for
causing overvoltage trips in
drives. Overvoltage could also
be caused by regenerative
loads. Loads such as cranes
and elevators feed back voltage
when they decelerate. Dynamic
braking circuits are installed to
shunt off this energy from the
drive, where they would other-
wise show up as overvoltage
on the dc link. Problems such
as improper installation can
result in overvoltage trips.
Overload problems are
usually load related and will be
addressed below.
Load profiling
To troubleshoot the interaction
between the load and the
motor, you have to understand
the relationship between
torque and current. A motor is
nothing but a device to turn
electrical energy (current) into
rotational mechanical energy
(torque), via the magical effects
of magnetism. What a load
demands of a motor is torque.
For all practical purposes, this
torque is directly proportional
to current used by the motor.
This should make perfect
sense, because we all know
that for constant-speed motors
— which include all motors
started across the line (with
electro-mechanic starters) —
voltage is, or should be, stable,
and current is the variable.
When a load demands more
torque and current than a
motor can supply, the result is
an overload condition. Over-
loading will cause overheating
of the motor. Motor controllers
will shut down the motor (and
thereby the load) rather than
allow permanent winding insu-
lation damage to occur.
Overloading is always relative to
time: a high overload will trip the
motor in a short time, while a
lower level of overload will take
longer to trip the motor.
When we want to evaluate the
impact of a load on the motor-
drive system, we have to
measure the current it draws. Of
course, this current draw typi-
cally varies over time as the load
varies. The measurement of
current over some period of time
is called load profiling. For load
profiling, the power-record func-
tion of Fluke power quality
analyzers is ideal for capturing a
trend line of current consumption
(and kW too, if you want it). A
cursor enables you to identify the
current values at different points
on the trend line, along with a
time stamp for those points. It is
not necessary to measure all
three phases of the induction
motor because the motor is a
balanced load. Before load
profiling, first make the current
imbalance measurement to make
sure the motor is healthy. If your
concern is nuisance tripping,
then pick the high leg and
measure that (an overload on
one leg will trip all three legs).
When load profiling, we are
looking for periods of especially
high current, relative to the full
load amps of the motor. Full load
amp information is available on
the nameplate of the motor. If
there is a service factor, the
range calculation should be made
on the basis of full load amps
times service factor.
While high current is the main
concern, low current should also
be avoided. A motor is most effi-
cient, and has the best power
factor, in the 60 to 80 percent
range of its full load amps. There
is no immediate penalty for
underloading — the motor will
not trip. In fact, many motors are
routinely oversized for the load,
on the theory that the motor is
less likely to trip from overload.
However, as is most often the
case, there is no free lunch. In
the case of underloading, the
energy company sends a higher
bill.
Continued from previous page
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2 Fluke Corporation Is it the drive, the motor or the load?
3. Is it the drive, the motor or the load? Fluke Corporation 3
Continued on next page
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Two different loads:
variable torque and
constant torque
Most drive systems are used
with variable torque or
constant torque loads. Variable
torque loads include fans and
rotary pumps. These are by far
the majority of loads, from an
energy consumption point of
view. When ASDs are used
with these loads, dramatic
energy savings can be realized.
For example, a fan at half-
speed (30 Hz) ideally uses only
one-eighth of the power of the
same fan at 60 Hz (we say
ideally, because there is always
some level of loss due to ineffi-
ciencies in the drive-motor-
load system). From a trou-
bleshooting point of view, the
important thing to realize is
that these variable torque loads
rarely cause overload-related
problems for drives (assuming
the load has been sized
correctly). That is because they
spend a lot of their time
running at lower speeds (less
than 60 Hz) and drawing less
current. If this were not the
case, that is, if the load
demanded full speed (and
torque) most or all of the time,
there would be no economic
justification; i.e., energy
savings, to install an ASD in
the first place. Sometimes these
loads will cause a trip at start-
up, but that is usually an
indication that the load has not
been sized correctly to the
drive. Another possibility is that
the load has changed. For
example, a bearing starting to
seize up demands more initial
torque to get the load going.
Constant torque loads can
be more challenging. Frictional
or gravitational loads are
constant torque loads. The key
thing to understand about
these loads is that they require
the same level of current (more
or less) at lower speeds. This
can be dangerous for the
motor. Motors are usually
cooled by fans built onto the
rotor; when the motor slows,
the fan cools less. Therefore
excessive heating can occur.
The danger is that motor over-
load circuits are built to
measure heat indirectly by
measuring current (there are
motors with heat sensors
embedded in their stators, but
these are obviously more
expensive). Here we have a
situation where normal current
draw at low speed can cause
overheating. The common solu-
tion is to install externally
powered fans to cool the motor.
Before we leave the subject
of load troubleshooting, it
should be noted that there is a
whole area of expertise having
to do with the mechanical link-
age of the motor and load.
These include vibration, shaft
alignment, motor mounting,
etc. These are obviously impor-
tant issues, but they are
outside of the scope of this arti-
cle.
Advanced motor
measurements
In ASD motor systems, there
are a few measurements that
need to be taken that would
not be taken in mechanical
starter (across the line) motor
systems. This is because the
fast switching, high-frequency
element of the PWM output
waveform causes special prob-
lems that the sine wave
doesn’t. At first glance, the
motor as a current-drawing
load looks like nothing but a
big set of inductors or coils
(stator windings), and the
nature of inductors is that they
filter out the high frequency
current elements. That is why
the current waveform looks like
a sine wave. But unfortunately,
those high-frequency elements
of the voltage waveform do not
get filtered out, and are capa-
ble of causing some mischief.
The first two of these meas-
urements should be made with
a ScopeMeter or with the Scope
function of a Fluke power
quality analyzer:
• Overvoltage reflections.
Measure phase-to-phase at
the motor terminals. The
leading edges of the PWM
pulses can have peak values
much higher (up to 200
percent in theory) than
normal. These overvoltage
reflections can cause
damage to motor windings.
These overvoltages are
clearly visible on the scope
waveform. Solutions fall into
three categories: shorten the
drive-motor cable length;
use a motor with higher
grade insulation, so-called
inverter duty motors; use
filters.
• Motor shaft voltages and
bearing currents. Measure
voltage rotor-to-frame
(ground), using stranded
wire or a carbon brush.
Motors run by sine waves
have a "normal" shaft/bear-
ing-to-frame voltage of 1 to
2 V. The PWM waveform can
cause breakdown voltages of
8 to 15 V to occur between
the shaft (more specifically,
the bearing) and the frame.
This damages bearings,
causing pitting and scarring.
Many solutions have been
proposed, but the most
common is the shaft ground-
ing device.
• Leakage current. Measure
with a current clamp around
all three phase conductors.
High frequencies cause
increased leakage between
stator windings and the
frame. This ground or leak-
age current can interfere
with control and communi-
cation signals. Common
solutions are the use of EMI
suppression cables or a
common mode choke.
What about harmonics at the
output of the drive? Wouldn’t
the PWM-turned-into-sine-
wave current-waveform
contain a lot of harmonics?
Absolutely. But we don’t have
to measure these. First of all,
they don’t get into the rest of
the power distribution system;
they only affect the motor.
Specifically, they cause addi-
tional heating in the motor.
However, motor and drive
manufacturers have addressed
this problem by supplying
higher grades of motor insula-
tion. In those cases where an
older motor is retrofit with an
ASD, the recommendation is
that the motor full load amp be
derated.