One is acting as a motor and another one as a generator. Brake testswinburnes of swinburnes testmain disadvantagesregcncrative or hopkinson. Ensure minimum resistance in the field circuit and check the brake drum for free rotation. Hopkinsons test is conducted at a no load b low load c full load d part load answer. The theory governing the specifics of hopkinson bar testing has been around for decades.
Then, knowing the armature and shunt cu losses at a given load current, efficiency can be calculated. Shpb system is an ideal and reliable high strain rate loading technique to measure dynamic properties of rocks under high strain rates 102e103 s 1. The kolsky bar, also known as the split hopkinson bar chen and song, 2011, is an experimental apparatus used to test materials at high strain rates, usually in the order of 102 to 104 1s. In dynamic testing the split hopkinson bar shb is used to measure. The maximum temperature rise in a large transformer is determined by the full load test. Test theories of special relativity give a mathematical framework for analyzing results of experiments to verify special relativity an experiment to test the theory of relativity cannot assume the theory is true, and therefore needs some other framework of assumptions that are wider than those of relativity. Here you will find complete resources and tools to study, practise online, track your progress, receive guidance and tips on passing the uk driving theory test. Advancements in the split hopkinson bar test by michael adam kaiser abstract the split hopkinson bar test is the most commonly used method for determining material properties at high rates of strain.
A hopkinson bar is defined as a perfectly elastic, homogeneous bar of constant crosssection. Hopkinson hopkinsons test aim to obtain performance of. The strain rate is found to be controlled by the stress and strain of the d. The hopkinson pressure bar is a 1d waveguide, usually of circular crosssection. Determination of dynamic fractureinitiation toughness using. Hopkinsons test is another useful method of testing the efficiency of a dc. Miller, basic electronics, a textlab manual, 7th dc motors, losses and efficiency, swinburnes test, hopkinsons test, field test. Methods of testing direct, indirect and regenerative testing brake test swinburnes test hopkinsons test fields test retardation test separation of stray losses in a d. Retardation or running down test this method is applicable to shunt motors and generators and is used for finding stray losses. Influence of specimens diameter in dynamic brazilian tests. A rope is wound round the pulley and its two ends are attached to two spring balances s 1 and s 2. Schematic of split hopkinson bar the theory of uniaxial wave propagation through elastic media leads to the following relations. One of the machines is made to act as a motor driving the other as a generator which supplies electric power to motor.
Mar 06, 2019 this method is an indirect method of testing a dc machine. Evolution of specimen strain rate in split hopkinson bar test. The stress, strain, and strain rate of a specimen during impact were evaluated with the aid of a stresswave. A stress wave will propagate in a hopkinson bar as a one. Since it is a regenerative test, the power drawn from mains is only needed to supply losses. Bhattacharyya, \split hopkinson pressure bar graphical analysis tool, experimental mechanics submitted. Ee 217 electrical technology labfor be 24 ece i sem 0 paul b.
To perform hopkinsons test on two identical dc machines. The strain rate is found to be controlled by the stress and strain of the deforming specimen, geometry the length and diameter of. Emslabmanual slideshare feb 09, 2014 separation of iron losses in dc machine hopkinson s test sumpner s test on single phase transformer transcript of emslabmanual 1. Backtoback test sumpners test on transformer definition. Beyond hopkinsons bar philosophical transactions of the.
Theory the efficiency of the dc machine can be accurately determined by the regenerative method, normally known as hopkinsons test. The method is based on threepoint bending tests at high loading rates, performed in an experimental device which is a modification of the classical split hopkinson pressure bar. It is a full load test and it requires two identical machines. The lo svaught test 20 every complex onetoone polynomial map is onto 22 chapter 3.
This test is called, backtoback test, regenerative test or sumpners test. The lab is equipped with various tests and monitoring equipment also. Test ptate bar incident bar transmitter bar free end,f 8 ft 7t 8 ft gr ep test plate bat bar 3 ifigure 1. This method is an indirect method of testing a dc machine. We present a procedure for measuring the dynamic fractureinitiation toughness of materials. Split hopkinson pressure bar graphical analysis tool.
The sumpner s test is another method of determining efficiency, regulation and heating under load conditions. The splithopkinson pressure bar, named after bertram hopkinson, sometimes also called a kolsky bar, is an apparatus for testing the dynamic stress strain response of materials. Using lamination theory, this provides an inplane youngs modulus e of 47. Dynamic rock tests using split hopkinson kolsky bar system. The split hopkinson bar shb, 24,25 which is also called the kolsky bar, has been used extensively for measuring the uniaxial stressstrain curves of various materials at high strain rates 10 2 to 10 4 s. Electrical machines 1 pdf notes em 1 pdf notes smartzworld. It is a full load test and it requires two identical machines which are coupled to each other. In this test the efficiency of the machine at any load is predetermined.
Because such layups are heavily dominated by fibre behaviour and carbon fibres exhibit very low strain rate dependence, this quasistatic reference will be used as a target value for the current tests. Electrical machinel dc laboratory manual grietelectrical and. Pdf test theory, classical test theory researchgate. The driving theory tough ten 40% of learner drivers can.
How many receptacles can be on a 20amp circuit a 30 b 40 c 50 d 10 answer. Shes written novels, picture books, biographies, and historical nonfiction, and each have been lauded as quality literature. Since it is a regenerative test, the power drawn from mains is. Numerical simulations of the kolsky compression bar test. Voices from the disaster that earned deborah hopkinson a sibert honor as one of the most distinguished informational books of 2012, cementing her status as a premier childrens nonfiction author. Here you will find complete resources and tools to study, practise online, track your progress, receive guidance and tips on. The technique was applied to investigate dynamic response in pure iron. In this two identical shunt machines are required which are coupled both. Diagrams and embeddings 24 diagram lemmas 25 every planar graph can be four coloured 25 ramseys theorem 26 the leibniz principle and in nitesimals 27 the robinson consistency theorem 27 the craig interpolation theorem 31 chapter 4. Hopkinsons test is also known as regenerative test, back to back and heat run test. Di erent designs have been used to load material specimens in compression or in tension. Hopkinson s test is another useful method of testing the efficiency of a dc machine. Jun 02, 2015 retardation or running down test this method is applicable to shunt motors and generators and is used for finding stray losses.
This new edition has been updated with the latest changes to the car. Pdf principles of electrical machines book by vk mehta. Hopkinsons test is a regenerative test and it is also called b. Methods of testing direct, indirect and regenerative testing brake test swinburne s test hopkinson s test field s test retardation test separation of stray losses in a d. Influence of specimens diameter in dynamic brazilian. Design customization and development of split hopkinson. Swinburnes test is the most commonly used and simplest method of testing of shunt and compound wound dc machines which have constant flux. Figure 1a shows a schematic of the basic compression apparatus. One of these two machines is operated as a generator to supply the mechanical power to the motor and the other is operated as a motor to drive the generator. The experimental results of the loading wave agreed well with the theoretical prediction.
This test overcomes the drawback of swinburnes test, which does not take any account of the stray load losses occurring in dc machines under loaded condition. While some emphasized that sociological theory or social theory is a i w hati st he or y. The highway code driving theory and hazard perception test. Free practice tests and hazard awareness practice for your car or motorcycle theory exams learn from thousands of questions in a virtually unlimited combination. Regenerative or hopkinsons test on dc machines is useful to determine the efficiency which the power. C machine efficiency by direct loading swinburnes method for determining efficiency regenerative or hopkinsons test retardation or running down test moment of inertia of the armature electric loading in retardation test. The results of this theory are summarized as follows. Assembly and details machine drawing pdf metal lathe tools, lathe parts.
A new impacttensioncompression testing technique based on a onedimensional elasticstresswave theory has been developed. Succinctly divided in 14 chapters, the book delves into important concepts of the subject which include armature reaction and commutation. The two machines are tested under loaded conditions so that stray load losses are accounted for. The specimen strain rate in the split hopkinson bar shb test has been formulated based on a onedimensional assumption. One of these two machines is operated as a generator to supply the mechanical power to the motor. The efficiency of the dc machine can be accurately determined by. Determination of dynamic fractureinitiation toughness. The machine under test is speeded up slightly beyond its normal speed and then supply is cut.
Th e course organizers rightly assumed that you already have an intuitive understanding of theory or soon will have. Online multiple choice questions electric machine design. Practice as many times as you need to get the perfect score. Hopkinson pressure bar, is schematically shown in fig. The tensions provided by the spring balances s 1 and s 2 are t 1 and t 2. In order to carry out this test, we require two identical d. The input to the motor is given by the supply mains. Hopkinsons test hopkinsons test is also known as regenerative test, back to back test and heat run test. To conduct sumpners test on two identical singlephase transformers and to determine its efficiency and regulation characteristics. Yet, their ubiquity notwithstanding, it is quite unclear what sociologists mean by the words theory, theoretical, and theorize. As such the efficiency, calculated by swinburnes test is comparatively higher than the actual one.
The strain rate is found to be controlled by the stress and strain of the. Coupled with the loading device, a highspeed photography system was used to measure the crack mouth opening. What is backtoback test sumpners test on transformer. Our decision to begin this lecture series on modern social theory with the question what is theory. Gabriel abend northwestern university theory is one of the most important words in the lexicon of contemporary sociology. Pdf evolution of specimen strain rate in split hopkinson. Hopkinsons test is another useful method of testing the efficiency of a dc machine. Hopkinsons test fields test retardation test separation of stray losses in a d. Dynamic rock tests using split hopkinson kolsky bar. Theory test practice free realistic uk driving theory tests. View lab report hopkinson from eee ee345 at national institute of technology, warangal. The official dvsa theory test for car drivers ebook. Aug 03, 2018 hopkinsons test is another useful method of testing the efficiency of a dc machine. This backtoback test is also known as the kapphopkinsons test.
No tools range quantity 1 mi ammeter 05a 1 2 mi ammeter 010a 1 3 mi voltmeter 0150v 1 4 mi voltmeter 050v 1 5 mi voltmeter 0600v 1 6 wattmeter 150v,5a,lpf 1 7. We advise you to read it before tackling our questions. Impacttension compression test by using a splithopkinson. The magnetic flux which does not follow the particularly intended path in a magnetic circuit is called a leakage flux b.
Test theory is concerned with methods and criteria for the construction, evaluation and comparison of tests, i. Pdf principles of electrical machines book by vk mehta and. One of the limitations of this test is the impossibility to use concrete disks with. The book principles of electrical machines book by vk mehta and rohit mehta is an ideal text for students who look to gain a current and clear understanding of the subject as all theories and concepts are explained with lucidity and clarity. William weiss and cherie dmello university of toronto. The full load test on a small transformer is very convenient, but on the large transformer, it is very difficult. Ssc je electrical important mcq pdf part 1 notedownload link of pdf given at end of post 1. Hopkinson s test hopkinson s test is also known as regenerative test, back to back test and heat run test.
It is a simple method of measuring motor output, speed and efficiency etc. Due to its simplicity, the brazilian test is performed under a wide variety of strain rates, allowing a complete mechanical characterisation of concrete under dynamic regime. The highway code driving theory and hazard perception. In hopkinson test, two identical shunt machines are required which are coupled both mechanically and electrically in parallel.
1144 1278 681 1146 1176 932 1573 869 1051 185 1415 394 771 566 1362 40 482 1580 1275 497 679 573 72 222 204 804 567 784 482 1044 925 1118 415