ABSTRACT
One century later, after Thomas Edison’s incandescent light bulb solid state
lighting is coming of age. Solid state electronics has been replacing their vacuum tube
predecessors for almost five decades. However solid state lighting had to wait for the
invention of the blue solid state light emitters, namely gallium nitride light emitting
diodes (LED).
High power lighting emitting diodes have begun to differentiate
themselves from their more common cousins, the indicator LED’s. Today, these
LED’s are designed to generate 10-100 lm per LED with efficiencies exceeding that of
incandescent and halogen bulbs, with great reduction in power consumption. After a
brief summary of the motivation for the development of high power LED’s, here it
describes the current state of high power LED technology [with reference to WHITE
LED] and challenges that lay ahead for the development of a true “solid state lamp”,
and demonstrates the record performance, reliability and other advantages of high
power colored and white LED’s and also a look at the future of the technology.
Monday, July 28, 2008
HY-WIRE THE ELECTRIC VEHICLE OF TOMORROW
ABSTRACT
HY-WIRE – This term is coined from the technologies used to drive this vehicle. i.e. Hydrogen fuel cells and By-Wire technologies.
The hydrogen fuel cells produce clean power. In this, the hydrogen is combined with oxygen to produce electricity required, the by-products being only heat and water vapor. The hydrogen required is compressed and stored in the vehicle. This makes the vehicle environment friendly. As the fuel cells are nearly twice as efficient as an internal combustion engine, the running cost will also be cheaper.
By-Wire technology replaces all the hydro-mechanical systems with electromagnetic systems. i.e. mechanical parts controlled by electronic equipments. This technology makes the use of cables obsolete and instead we use wires to pass the impulses to a microcontroller, which in turn controls the vehicle.
This results in the production of a purely electric vehicle where the only moving things other than the protons, electrons, water and the motor are the wheels and suspension.
HY-WIRE – This term is coined from the technologies used to drive this vehicle. i.e. Hydrogen fuel cells and By-Wire technologies.
The hydrogen fuel cells produce clean power. In this, the hydrogen is combined with oxygen to produce electricity required, the by-products being only heat and water vapor. The hydrogen required is compressed and stored in the vehicle. This makes the vehicle environment friendly. As the fuel cells are nearly twice as efficient as an internal combustion engine, the running cost will also be cheaper.
By-Wire technology replaces all the hydro-mechanical systems with electromagnetic systems. i.e. mechanical parts controlled by electronic equipments. This technology makes the use of cables obsolete and instead we use wires to pass the impulses to a microcontroller, which in turn controls the vehicle.
This results in the production of a purely electric vehicle where the only moving things other than the protons, electrons, water and the motor are the wheels and suspension.
FLEXIBLE SHIP ELECTRIC POWER SYSTEM DESIGN
INTRODUCTION
The first electrical power system was installed on the USS Trenton in 1883 (Ykema 1988). The system consisted of a single dynamo supplying current to 247 lamps at a voltage of 10 volts d.c. Until the 1914 to 1917 period, the early electrical power systems were principally d.c. with the loads consisting mainly of motors and lighting. It was during World War I that 230 volt, 60 hertz power systems were seriously introduced into naval vessels. Since World War II the ship’s electrical systems have continued to improve, including the use of 4,160 volt power systems and the introduction of electronic solid-state protective devices.
Protective devices were developed to monitor the essential parameters of electrical power systems and then through built-in logic, determine the degree of configuration of the system necessary to limit the damage to continuity of electric service for the vessel (Ykema 1988).
Fuses are the oldest form of protective devices used in electrical power systems in commercial systems and on navy vessels. Circuit breakers were added around the turn of the century. The first electronic solid-state over current protective device used by the Navy was installed on the 4,160 power system in Nimitz class carriers. Navy systems of today supply electrical energy to sophisticated weapons systems, communications systems, navigational systems, and operational systems. To maintain the availability of energy to the connected loads to keep all systems and equipment operational, the navy electrical systems utilize fuses, circuit breakers, and protective relays to interrupt the smallest portion of the system under any abnormal condition.
The existing protection system has several shortcomings in providing continuous supply under battle and certain major failure conditions. The control strategies which are implemented when these types of damage occur are not effective in isolating only the loads affected by the damage, and are highly dependent on human intervention to manually reconfigure the distribution system to restore supply to healthy loads.
This paper discusses new techniques which aim to overcome the shortcomings of the protective system. These techniques are composed of advanced monitoring and control, automated failure location, automated intelligent system reconfiguration and restoration, and self-optimizing under partial failure.
These new techniques will eliminate human mistakes, make intelligent reconfiguration decisions more quickly, and reduce the manpower required to perform the functions. It will also provide optimal electric power service through the surviving system. With fewer personnel being available on ships in the future, the presence of this automated system on a ship may mean the difference between disaster and survival.
The first electrical power system was installed on the USS Trenton in 1883 (Ykema 1988). The system consisted of a single dynamo supplying current to 247 lamps at a voltage of 10 volts d.c. Until the 1914 to 1917 period, the early electrical power systems were principally d.c. with the loads consisting mainly of motors and lighting. It was during World War I that 230 volt, 60 hertz power systems were seriously introduced into naval vessels. Since World War II the ship’s electrical systems have continued to improve, including the use of 4,160 volt power systems and the introduction of electronic solid-state protective devices.
Protective devices were developed to monitor the essential parameters of electrical power systems and then through built-in logic, determine the degree of configuration of the system necessary to limit the damage to continuity of electric service for the vessel (Ykema 1988).
Fuses are the oldest form of protective devices used in electrical power systems in commercial systems and on navy vessels. Circuit breakers were added around the turn of the century. The first electronic solid-state over current protective device used by the Navy was installed on the 4,160 power system in Nimitz class carriers. Navy systems of today supply electrical energy to sophisticated weapons systems, communications systems, navigational systems, and operational systems. To maintain the availability of energy to the connected loads to keep all systems and equipment operational, the navy electrical systems utilize fuses, circuit breakers, and protective relays to interrupt the smallest portion of the system under any abnormal condition.
The existing protection system has several shortcomings in providing continuous supply under battle and certain major failure conditions. The control strategies which are implemented when these types of damage occur are not effective in isolating only the loads affected by the damage, and are highly dependent on human intervention to manually reconfigure the distribution system to restore supply to healthy loads.
This paper discusses new techniques which aim to overcome the shortcomings of the protective system. These techniques are composed of advanced monitoring and control, automated failure location, automated intelligent system reconfiguration and restoration, and self-optimizing under partial failure.
These new techniques will eliminate human mistakes, make intelligent reconfiguration decisions more quickly, and reduce the manpower required to perform the functions. It will also provide optimal electric power service through the surviving system. With fewer personnel being available on ships in the future, the presence of this automated system on a ship may mean the difference between disaster and survival.
ELECTRO DYNAMIC TETHER
ABSTRACT
The word meaning of tether is a rope or chain used to fasten animals. In space tethers have an application similar to their word meaning. Here we have satellites and spacecrafts instead of animals. A tether if connected between two space crafts (one having lower orbital altitude and the other at a larger orbital altitude) momentum exchange can take place between them. Then the tether is called a momentum exchange space tether.
But tethers are being made of electrically conducting materials like aluminium or copper and they provide an additional advantage. They are called electrodynamic tethers. They can convert orbital energy into electrical energy. It works on the principle of electromagnetic induction. Also when the conductor moves through a magnetic field, charged particles in the conductor experience an electromagnetic force perpendicular to both the direction of motion and field. This can be used for power generation. This can be use for orbit raising or lowering, debris removal. Another application of tethers discussed here is artificial gravity inside space crafts.
The word meaning of tether is a rope or chain used to fasten animals. In space tethers have an application similar to their word meaning. Here we have satellites and spacecrafts instead of animals. A tether if connected between two space crafts (one having lower orbital altitude and the other at a larger orbital altitude) momentum exchange can take place between them. Then the tether is called a momentum exchange space tether.
But tethers are being made of electrically conducting materials like aluminium or copper and they provide an additional advantage. They are called electrodynamic tethers. They can convert orbital energy into electrical energy. It works on the principle of electromagnetic induction. Also when the conductor moves through a magnetic field, charged particles in the conductor experience an electromagnetic force perpendicular to both the direction of motion and field. This can be used for power generation. This can be use for orbit raising or lowering, debris removal. Another application of tethers discussed here is artificial gravity inside space crafts.
ELECRICAL POWER LINE NETWORKING FOR A SMART HOME
ABSTRACT
Electrical power line networking is one of the several ways to connect computers in a home. It uses existing electrical wiring for networking. Power line networking is based on the concept of “no new wires”. With power line networking, you will able to put your desktop PCs anywhere you like, instead of being put near a phone outlet. All you need to do is plug your PC or other devices into the closest electrical outlet. A home owner can create an entire home network linking: personal computers, printers, music equipments, internet access etc.
There are two competing technologies. The old technology was called “passport” technology by a company named Intelogis. The new technology is called “power packet” technology by Intellon. Power packet has an ideal option to serve as the backbone for multitechnology home network.
The main advantages of power line network are,
1. It uses existing electrical wiring.
2. Every room of a typical house has several electrical outlets.
3. A printer or any other device that does not need to be directly connected to computer does not have to be physically it.
Power line networking technology succeeds in turning the average home’s electrical outlets into high speed network. Also it is compatible with other home networking technology. Thus it has tremendous promise for the future.
Electrical power line networking is one of the several ways to connect computers in a home. It uses existing electrical wiring for networking. Power line networking is based on the concept of “no new wires”. With power line networking, you will able to put your desktop PCs anywhere you like, instead of being put near a phone outlet. All you need to do is plug your PC or other devices into the closest electrical outlet. A home owner can create an entire home network linking: personal computers, printers, music equipments, internet access etc.
There are two competing technologies. The old technology was called “passport” technology by a company named Intelogis. The new technology is called “power packet” technology by Intellon. Power packet has an ideal option to serve as the backbone for multitechnology home network.
The main advantages of power line network are,
1. It uses existing electrical wiring.
2. Every room of a typical house has several electrical outlets.
3. A printer or any other device that does not need to be directly connected to computer does not have to be physically it.
Power line networking technology succeeds in turning the average home’s electrical outlets into high speed network. Also it is compatible with other home networking technology. Thus it has tremendous promise for the future.
Tuesday, July 22, 2008
ELECTRICAL IMPEDANCE TOMOGRAPHY
ABSTRACT
This paper is concerned with a still emerging medical imaging modality called Electrical Impedance Tomography. This process involves constructing images of the electrical impedance of the body’s interior based upon measurements of voltage and current made at the body’s surface. The electrical impedance accounts for both resistivity and permittivity. This paper shows how permittivity can be exploited to improve the performance of an electrical impedance imaging system. The explicit use of the independent information in the data due to the permittivity will enhance a system’s ability to distinguish objects in the interior of a body.
DIGITAL TESTING OF HIGH VOLTAGE CIRCUIT BREAKER
ABSTRACT
The functionality of high voltage circuit breaker is tested in high power laboratories. With the advancement of power system need for high voltage circuit breaker has increased a lot, as they play an important role in transmission and distribution. Among the tests, Routine tests are performed on every piece of circuit breaker in the premises of the manufacturer where as Type tests are performed in a high voltage laboratory. The test is performed on sample pieces of circuit breaker of each type to confirm their characteristics and rated capacities according to their design. Digital testing of high voltage circuit breaker employs a software product for testing of a breaker model, once its characteristic fingerprints are obtained from the standard tests. High-resolution measurements of current and voltage are done in the critical period. The arc voltage is measured with standard broadband RCR type voltage divider and current with special Rogowski coil.
BEAMED MICRO WAVE POWER TRANSMISSION
ABSTRACT
Beamed micro wave power transmission may be thought of as extending our two dimensional power transmission networks to the three dimensional power transmission system in which power is beamed from earth to space or power collected in space is beamed back to the earth.
Solar energy is an unlimited source of energy. The electrical energy obtained from the sun by satellites in geostationary orbits is transmitted to earth. Unlike x-rays or ultra-violet radiation, microwaves are non-ionizing and are one million times too weak to cause harm. The only perceivable effect is heating, but since the power density of the beam near the receivers on earth is about 20 milliwatts per square centimeter, one-fourth of natural sunlight, the heat generated is so slight that a person walking through would feel nothing. Manufacturing costs are not a problem either since materials would be negligible (when compared with the relatively giant profits that a solar power satellite would generate).
ADAPTIVE OPTICS IN GROUND BASED TELESCOPES
INTRODUCTION
Adaptive optics is a new technology which is being used now a days in ground based telescopes to remove atmospheric tremor and thus provide a clearer and brighter view of stars seen through ground based telescopes. Without using this system, the images obtained through telescopes on earth are seen to be blurred, which is caused by the turbulent mixing of air at different temperatures causing speed & direction of star light to vary as it continually passes through the atmosphere
.
Adaptive optics in effect removes this atmospheric tremor. It brings together the latest in computers, material science, electronic detectors, and digital control in a system that warps and bends a mirror in a telescope to counteract, in real time the atmospheric distortion.
The advance promises to let ground based telescopes reach their fundamental limits of resolution and sensitivity, out performing space based telescopes and ushering in a new era in optical astronomy. Finally, with this technology, it will be possible to see gas-giant type planets in nearby solar systems in our Milky Way galaxy. Although about 100 such planets have been discovered in recent years, all were detected through indirect means, such as the gravitational effects on their parent stars, and none has actually been detected directly.
Sunday, July 20, 2008
POLYFUSE
ABSTRACT
A fuse is a one time over current protection device employing fusible link that melts after the current exceeds a certain level for a certain length of time. Typically, a wire or chemical compound breaks the circuit when the current exceeds the rated value.
Polyfuse is a new standard for circuit protection .It is resettable. Technically, Polyfuses are not fuses but polymeric positive temperature coefficient thermistors (PPTC). Re-settable fuses provide over current protection and automatic restoration.
CONTENTS
1. INTRODUCTION
2. THE BASICS
3. PRINCIPLE OF OPERATION
4. OPERATING PARAMETERS
5. DESIGN CONSIDERATIONS
6. DESIGN CRITERIA
7. DIFFERENT TYPES OF POLYFUSES
8. EDGES OVER CONVENTIONAL FUSES
9. APPLICATIONS
10. CONCLUSION
11. REFERENCE
A fuse is a one time over current protection device employing fusible link that melts after the current exceeds a certain level for a certain length of time. Typically, a wire or chemical compound breaks the circuit when the current exceeds the rated value.
Polyfuse is a new standard for circuit protection .It is resettable. Technically, Polyfuses are not fuses but polymeric positive temperature coefficient thermistors (PPTC). Re-settable fuses provide over current protection and automatic restoration.
CONTENTS
1. INTRODUCTION
2. THE BASICS
3. PRINCIPLE OF OPERATION
4. OPERATING PARAMETERS
5. DESIGN CONSIDERATIONS
6. DESIGN CRITERIA
7. DIFFERENT TYPES OF POLYFUSES
8. EDGES OVER CONVENTIONAL FUSES
9. APPLICATIONS
10. CONCLUSION
11. REFERENCE
EDDY CURRENT BRAKES
ABSTRACT
This is an electric braking system which works on the principle that eddy current produced in it opposes the driving torque. This opposing torque is used to brake the automobiles. Mainly this system is purely based on Faraday’s laws of electromagnetic induction and Lenz’s law.
For operating this a control switch is provided on the steering column in a position for easy manual. The skidding and complexity of mechanical braking system can be minimized by this system. Also the wear and tear of the vehicles can be reduced.
Since researches are going on to eliminate some of the disadvantages of this system, we can accept it to be the norm one in a few years of time.
CONTENTS
1. INTRODUCTION
2. PRINCIPLE OF OPERATION
3. CONSTRUCTION
4. WORKING
5. EDDY CURRENT BRAKE IN TRAINS
6. BRAKING POWER CALCULATIONS
7. EDDY CURRENT BRAKE REQUIREMENTS
8. MOUNTING AND INSTALLATION
9. ADVANTAGES
10. DISADVANTAGES
11. APPLICATIONS
12. CONCLUSION
13. REFERENCES
This is an electric braking system which works on the principle that eddy current produced in it opposes the driving torque. This opposing torque is used to brake the automobiles. Mainly this system is purely based on Faraday’s laws of electromagnetic induction and Lenz’s law.
For operating this a control switch is provided on the steering column in a position for easy manual. The skidding and complexity of mechanical braking system can be minimized by this system. Also the wear and tear of the vehicles can be reduced.
Since researches are going on to eliminate some of the disadvantages of this system, we can accept it to be the norm one in a few years of time.
CONTENTS
1. INTRODUCTION
2. PRINCIPLE OF OPERATION
3. CONSTRUCTION
4. WORKING
5. EDDY CURRENT BRAKE IN TRAINS
6. BRAKING POWER CALCULATIONS
7. EDDY CURRENT BRAKE REQUIREMENTS
8. MOUNTING AND INSTALLATION
9. ADVANTAGES
10. DISADVANTAGES
11. APPLICATIONS
12. CONCLUSION
13. REFERENCES
CIRCUIT BREAKER MAINTENANCE BY MOBILE AGENT SOFTWARE TECHNOLOGY
Abstract
Circuit breakers are crucial components for power system operation. The currently adapted time-directed maintenance strategy and the emerging new condition-based strategy require a flexible information processing technique and software architecture. In this paper, mobile agent software has been applied in implementing circuit breaker maintenance and repair tasks. Several potential application scenarios have been described and the relevant software features have been discussed. The benefits of using the mobile agent techniques are discussed at the end.
Contents
I. Introduction
II. Circuit Breaker Maintenance Tasks
III. Mobile Agent Software
IV. Application Scenarios
A. Information Storage and Retrieval
B. Creating Circuit Breaker Failure Reports
C. Circuit Breaker Monitoring
D. Security Consideration
E. Logging and Experience Sharing
F. Cost-Benefit Analysis
G. Other
V. Summary
VI. Conclusion
VII. References
Circuit breakers are crucial components for power system operation. The currently adapted time-directed maintenance strategy and the emerging new condition-based strategy require a flexible information processing technique and software architecture. In this paper, mobile agent software has been applied in implementing circuit breaker maintenance and repair tasks. Several potential application scenarios have been described and the relevant software features have been discussed. The benefits of using the mobile agent techniques are discussed at the end.
Contents
I. Introduction
II. Circuit Breaker Maintenance Tasks
III. Mobile Agent Software
IV. Application Scenarios
A. Information Storage and Retrieval
B. Creating Circuit Breaker Failure Reports
C. Circuit Breaker Monitoring
D. Security Consideration
E. Logging and Experience Sharing
F. Cost-Benefit Analysis
G. Other
V. Summary
VI. Conclusion
VII. References
BRUSHLESS DC MOTOR
ABSTRACT
Brushless DC Motor (BLDC) is one of the motors gaining popularity.
As their there name implies, BLDC motors do not use brushes for
Commutation; instead they are electronically commutated. BLDC motor
Have many advantages over other motors.
They have better speed to torque ratio, high dynamic response, long operating
Period, noiseless operation, higher speed range, rugged construction .
Also torque delivered to the rotor size is higher. Making it useful in application
Where space and weights are critical factors.
With these advantages BLDC motor find wide spread application in
Automotive, appliances, aerospace, medical instrumentation and automation industry
Brushless DC Motor (BLDC) is one of the motors gaining popularity.
As their there name implies, BLDC motors do not use brushes for
Commutation; instead they are electronically commutated. BLDC motor
Have many advantages over other motors.
They have better speed to torque ratio, high dynamic response, long operating
Period, noiseless operation, higher speed range, rugged construction .
Also torque delivered to the rotor size is higher. Making it useful in application
Where space and weights are critical factors.
With these advantages BLDC motor find wide spread application in
Automotive, appliances, aerospace, medical instrumentation and automation industry
Subscribe to:
Posts (Atom)
