The engine being tested spins a disk in the dynamometer. Goudsmit excentric eddy current separator the eddy current separators manufactured by goudsmit have been used widely for decades. However, an eddy current brake cannot provide a holding torque and so may be used in combination with mechanical brakes, for example, on overhead cranes. Electromagnetic eddy current engineering is simply better by design. List and describe the more commonly used equipment in an electric substation.
Eddy current technique is an important electromagnetic nondestructive evaluation technique that is widely used in power, aerospace, petrochemical and other industries for detection of surface. Mechanical variable speed drives belt and chain drives with adjustable diameter sheaves metallic friction dr ives 7. Determination of machine parameters the nameplate gives sufficient information on the rated current, power, frequency, voltage, winding temperature, and stator winding c n. The eddy current drive is well suited for this application for many reasons. The ec14 instrument is capable of recording the inspection. Eddy current sensor industry, 2018 market research report the global and chinese eddy current sensor industry, 202023 market research report is a professional and indepth study on the current state of the global eddy current sensor industry with a focus on the chinese market. Eddy current free download as powerpoint presentation. Lecture 6 three phase induction motors cairo university. If a current is passed through a nerators consist of two basic coil the carr exc usu ond e wound in coils. In industrial terms, ac drive is also called as variable frequency drive vfd, variable speed drive vsd, or adjustable speed drive asd.
W hen bearing fluting or other evidence of electrical damage was clear the cause was frequently believed to be due to some. Eddy current loss free download as powerpoint presentation. A dynamometer is a load device which is generally used for measuring the power output of an engine. The highline automation ec14 has a frequency range of 40hz to2 mhz the instrument will meet or exceed the requirements of appendix a.
Eddy current drives, also known generically as magnetic drives, eddy current clutches or magnetic clutches are driven at constant speed by an ac motor and utilize a simple electromagnetic device to control torque and speed to the driven load. Techniques for eddy current reduction in magnetic drives using. Sectors oa and oc are not in b, but provide return conducting paths for charges displaced along ob to return from b to o. The dc motor drive also provides the high current torque, 400 % more than the rated continuous torque. Eddy current clutch hydrostatic drives wound rotor motor dc drives. The report provides key statistics on the market status of the eddy current sensor manufacturers and is a. Applications of dc machines motors and generators circuit. Since there is no contact with a brake shoe or drum, there is no mechanical wear. They will occur when the conductor experiences a changing magnetic field. These circulating currents are called eddy currents. The instrument is a dual channel dual frequency instrument. The outer surface of the magnet consists of a series of magnetic poles having alternating north and south poles, which are magnetized at varying strength by a lowpower dc current, referred to as excitation current.
In fact, for almost all applications involving soft iron, eddy currents are the dominant source of loss. In eddy current testing, electrical currents eddy currents are generated in a conductive material by a changing magnetic field. Dynamometer powerpoint ppt presentations powershow. Other classes of electrical damage, such as eddy currents have, at times, been confused with this newly redefined class of electrically caused bearing damage. Computer based eddy current test instrument manufactured by highline automation. A reduced voltage is applied to the stator terminal so that the rated current flows through the stator winding. The power split device is a clever gearbox that hooks the internal combustion engine and d. Eddy current techniques in ndeeddy current techniques in nde. How dynamatic technology works adjustable speed drive system. The purpose of this volume is to present the basic concepts of eddy currents, to explain how eddy currents are generated and distributed, to point out how the specimens magnetic and electrical effects relate to eddy currents, and. Electronic system for nondestructive testing using eddy. Nondestructive testing ndt is a mechanism used by engineers to detect defects in materials and structures, either during manufacturing or while in service. Eddy current techniques in ndeeddy current techniques in nde lalita udpa nondestructive evaluation laboratory department of electrical and computer engineering miccg s euvesyhigan state university east lansing, mi 48824 wcndt p f w k h d b a il 15 2012wcndt preconference workshop.
Explore eddy current brakes with free download of seminar report and ppt in pdf and doc format. Input fixed speed motor output variable speed load 6. Pulsed eddy current testing pect inspection technique innospection limited unit 1, howemoss avenue, kirkhill industrial estate, dyce, ab21 0gp, aberdeen, united kingdom. Pdf design and fabrication of an eddy current brake.
Drive efficiency eddy current vs variable frequency drives. Abstract the frosted, fluted or corrugated pattern often found on the surface of the inner or outer race of an antifriction bearing is often the result of electrical damage. Electrical drives about 50% of electrical energy used for drives can be either used for fixed speed or variable speed 75% constant speed, 25% variable speed. High quality eddy current testing solutions for complete inspections. Design of a vibration isolation system using eddy current. The dc motor drive is a type of amplifier or power modulator that integrate between the controller and a dc motor. They are composed of a conveyor belt system with a rapidly rotating magnetic rotor that creates an induction field by means of magnetic poles.
Manual for the s yllabi contained in iaeat e cd o c628. Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical. Eddy currents 15 eddy currents an eddy current is a swirling current set up in a conductor in response to a changing magnetic field. Several kinds of dynamometers are common, some of them being referred to as breaks or break dynamometers. A knowledge of probable defect type, position, and orientation. A diagram that depicts the changes in electrical impedance that occur in an eddy current coil as test variables change. Eddy current drives power 312014 we are a force to reckon with in offering a large range of eddy current drives which are preferred as they have traits such as need minimum maintenance, available in power range of 1hp to 120 hp with variety of applications and also find applications in speed or torque control operations.
Has a medium starting current, the highest locked rotor torque 275% of full load, no. Rated from 5 to 2,500 hp 4 to 1,864 kw wet and dry gap configurations. Eddy current brake design for operation with extreme. Of course, variable frequency drives vfds and ac motors are now offering an alternative to dc drives and motors, but there are many other applications where dc drives are extensively used including crane and hoists, elevators, spindle drives, winders, paper production machines, crushers, etc. Ppt eddy current powerpoint presentation free to view. Nondestructive techniques based on eddy current testing.
Eddy current drives power 3 12014 we are a force to reckon with in offering a large range of eddy current drives which are preferred as they have traits such as need minimum maintenance, available in power range of 1hp to 120 hp with variety of applications and also find applications in speed or torque control operations. Thus, when a motor core is rotated in a magnetic field, a voltage, or emf, is induced in the coils. Ac drives are used to drive the ac motor especially three phase induction motors because these are predominant over other motors in most of the industries. This important and growing industry is involved in applying these.
Probes of appropriate design and frequency must be used. Eddy current testing eddy current testing is particularly well suited for detecting surface cracks but can also be used to make electrical conductivity and coating thickness measurements. At any instant the actual field of the eddy currents is a superposition of these. A graphic presentation is shown in figure 6 of the normal operating region. Eddy current inspection is based on the principle of electromagnetic induction. Faraday was a chemist in england during the early 1800s and is credited with the discovery of electromagnetic induction, electromagnetic rotations, the magnetooptical effect, diamagnetism, and other phenomena. The eddy current drive has been used on small through large variable speed metal forming presses for over 50 years.
In eddy current drive, speed is varied by varying the field of eddy current coupling. Timehonored and wellrespected manufacturers of eddy current dynamometers, were acquired by dyne systems in 2002. Technical specification eddycurrent dynamometer w series. Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. Similar to hysteresis loss, eddy current loss also increases the temperature of the magnetic material. Material defects cause interruptions in the flow of the eddy currents. We have the most extensive experience, and we develop the highest quality ect inspection products. Eddy current inspection involves initial setup and calibration procedures with known reference standards of the same material as the part. Eddy current drive is an electromechanical device, which operates on eddy current principle. Department of energys does advanced manufacturing office amo with support from the copper development association cda. Variable frequency drives and dc drives operate by electronically altering the input power to control the speed of the motor. Find powerpoint presentations and slides using the power of, find free presentations research about eddy current braking system ppt.
Hydraulic variable speed drives hydrodynamic types hydrostatic types 8. The system based on the ecscan architecture makes use of a new probe excitation block capable of simultaneously. In this presentation, we will be covering variable frequency drives vfds and their theory, application, and troubleshooting. Rao nondestructive evaluation division metallurgy and materials group indira gandhi center for atomic research kalpakkam 603 102, tn, india email. As the eddy current drive efficiency drops rapidly at loads below 70%, energy savings are extremely sensitive to the load profile and duty. A second abrupt change in b f produces a second set of eddy currents, and so forth. Disadvantages include requiring a second set of test cell services electrical power and. Eddy current technique is an important electromagnetic non. This manual generally covers all model numbers beginning with the letters dcd, followed by a hyphen and a number between 2 and 225, and ending with a hyphen followed by a number between 4041 and 4181. No load current, i 0 has been directly measured by the ammeter. The engine starts only after the vehicle attains a certain speed. The probe should fit the geometry of the part and the coil must produce eddy currents that will be disrupted by the flaw. Surface probes can be very small in size to allow accessibility to confined areas. It takes the low current and then converts it into a high current which is appropriate for the motor.
Longer core adds more steel to the design, which reduces losses due to lower operating. Eddy current losses are the result of faradys law, which states that, any change in the environment of a coil of wire will cause a voltage to be induced in the coil, regardless of how the magnetic change is produced. Has a medium starting current, the highest locked rotor torque 275% of full load, no defined breakdown torque, and greater than 5% slip. The more load on the motor, the higher the slip, and the higher the load current. This current path transforms from the stator to the rotor by transformer action, and flows through the rotor bars. Design of a vibration isolation system using eddy current damper partha paul, chetan ingale and bishakh bhattacharya abstract this article aims at modeling, analysis and design of a passivevibration isolation system using a magnetic damper with high efficiency and compactness. It is mathematically convenient to define the standard depth of penetration where the eddy current is 1e 37% of its surface value. From these equations, it can be seen that eddy current voltage is proportional to.
Eddy current dynamometer technomech is the leading manufacturer and supplier of the engine test system equipments. Electrical current passes through coils surrounding the disk, and induce a magnetic resistance to the motion of the disk. Basic principles a inducing a current into a coil creates a magnetic field in blue. Chapter 16 current transformer design university of north. Here a small surface probe is scanned over the part surface in an attempt to detect a crack. An eddy current or waterbrake dynamometer, with electronic control combined with a variable frequency drive and ac induction motor, is a commonly used configuration of this type. Typically, the methods used are ultrasonics, radiography, magnetic particle, eddy current, dye penetrant and visual methods. Conventionally, eddy current drive is used for varying the speed of cane carriers in sugar plant. Design and damping analysis of a new eddy current damper.
The eddy current density, and thus the strength of the response from a flaw, is greatest on the surface of the metal being tested and declines with depth. Sep 21, 20 introduction to electric drives module 1 components in electric drives sensors sensors voltage, current, speed or torque is normally required for closedloop operation or protection electrical isolation between sensors and control circuit is needed for the reasons previously explained the term sensorless drives is normally. Is it costeffective to replace old eddycurrent drives. Kinds of drive ac drives dc drives variable frequency drives variable speed drives adjustable speed drives 5. Finger probe hareesha n g, dept of aero engg, dsce 38 39. In response, the test object generates eddy currents to oppose the alternating.
Eddy current brakes seminar report, ppt, pdf for electrical. Electrical variable speed drives dc motor drives eddy current motor drives ac motor drives 9. Remove any alignment tools and use the soft metal hammer to drive the dowels into the smaller holes until the dowel is flush with the handle face. Applications of dc machines in the present day world, the electrical energy is generated in bulk in the form of an alternating current. Their low initial cost, simplicity, and reliability have made them favorites of press users and manufacturers all over the world. For more information on eddy current drives and other variable speed drives, refer to his application guideline for variable speed pumping at. Has a medium starting current, high locked rotor torque 200 250% of full load, low breakdown torque 190 200% of full load, and less than 5% slip. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. The annual energy consumption of the existing system or eddy current baseline is calculated in table 2.
Eddy current dynamometers are electromagnetic load devices. Iron use of thinner gauge, lower loss core steel reduces eddy current losses. Schenck pegasus gmbh technical specification eddycurrent dynamometer w series h. In a conductor, electrons swirl in a plane perpendicular to the magnetic field. The rotation speed results in a rapidly fluctuating changing magnetic field. The strength of these eddy currents can be measured. Eddy current inductor low pass filter free 30day trial. The power split device helps the vehicle to accelerate to a speed of about 15kmhr before switching on the gasoline engine. Energy efficient technologies in electrical system bureau of energy efficiency 182 table 10. Eddy current controls flexible and precise control options for all your adjustable speed drives and brakes. Kinds of drive ac drives dc drives variable frequency drives variable speed drives adjustable. Eddy currents induced currents that circulate throughout the volume of a material.
Eddy current techniques employ alternating currents applied to a conducting coil held close to the test object. As these currents are not responsible for doing any useful work, and it produces a loss i 2 r loss in the magnetic material known as an eddy current loss. Differentiate between the various types of generating electric power stations. Jul 11, 20 hydraulic variable speed drives electrical variable speed drives 6. An eddy current drive, also known generically as a magnetic drive, eddy current clutch or magnetic clutch, is an electromechanical variable speed drive that. Eddy current drive it is a type of electrical drive. Leaders in eddy current drives eddy current dynamometers. Design and damping analysis of a new eddy current damper for aerospace applications latin american journal of solids and structures 2016 19972011 noncontact, nonleakage and easy implementation, become a candidate to suppress vibrations of a. Core loss includes hysteresis and eddy current losses of the core. Variable frequency drives and dc drives operate by electronically altering. Magnetic drives or couplings using permanent magnets are well known for their. Theory and applications article pdf available in proceedings of the ieee 8010. Eddy current controls adjustable speed drive controls.
Powermag has been the market leader in manufacturing and developing eddy current variable speed drives and eddy current dynamometers. Ex b confined to a small region of rotating disk ob moves across b and emf is induced induced circulation of eddy currents. They are mainly used in supplying excitation of small and medium range alternators. I2 mlrni 2 0, amps 164 imiin, amps 165 the above equation has shown graphically in figure 164, that th e higher the exciting current, im or core. Zetec is the industry leader for costeffective eddy current testing ect in complex applications. Eddy current testing has its origins with michael faradays discovery of electromagnetic induction in 1831. Eddy current loss electromagnetic induction physical.
Massachusetts institute of technology mit opencourseware. Hugh boyanton shaft grounding systems, inc albany, or. Massachusetts institute of technology department of electrical engineering and computer science 6. By lenzs law, the swirling current sets up a magnetic field opposing the change. An example to test the proportionality between pe in the copper disc and. Dec 01, 2016 electrical drives drives are systems employed for motion control require prime movers drives that employ electric motors as prime movers are known as electrical drives 2. View and download powerpoint presentations on eddy current braking system ppt.
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