Magnetism And Hysteresis Evidence
Magnetism And Hysteresis
Section titled “Magnetism And Hysteresis”Evidence status: generated from processed OCR/PDF text. Treat each hit as a source-location aid until the passage is checked against the scan.
5287 hits
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14 sources
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256 sections
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What This Theme Gathers
Section titled “What This Theme Gathers”Passages involving magnetism, magnetic flux, permeability, reluctance, hysteresis, effective resistance, molecular friction, lag, magnetic loss, and hysteresis motor language.
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Modern Reading Prompt
Separate magnetic material behavior from circuit equivalents. Steinmetz often lets magnetic loss appear as an equivalent electrical quantity, which is easy to flatten in modern summaries.
Interpretive Boundary
A Wheeler-style reading may treat hysteresis as field lag or memory, but the archive must keep that reading distinct from Steinmetz’s explicit engineering treatment.
Matched Aliases
Section titled “Matched Aliases”| Alias | Hits |
|---|---|
magnetic | 3465 |
magnetic flux | 978 |
hysteresis | 543 |
magnetic field | 490 |
magnetism | 406 |
magnetizing | 240 |
effective resistance | 224 |
reluctance | 193 |
permeability | 120 |
magnetization | 80 |
hysteresis loss | 54 |
hysteresis motor | 22 |
molecular friction | 16 |
magnetic lag | 1 |
Source Distribution
Section titled “Source Distribution”Section Hits
Section titled “Section Hits”Representative Source-Located Passages
Section titled “Representative Source-Located Passages”Chapter 12: Effective Resistance And Reactance - 208 hit(s)
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CHAPTER XII EFFECTIVE RESISTANCE AND REACTANCE 89. The resistance of an electric circuit is determined : 1. By direct comparison with a known resistance (Wheat- stone bridge method, etc.). This method gives what may be called the true ohmic resist- ance of the circuit. 2. By the ratio: Volts consumed in circuit Ampere ...... X = Total current is the effective reactance, and Wattless component of current Total e.m.f. is the effective suscepta7ice of the circuit. While the true ohmic resistance represents the expenditure of power as heat inside of the electric conductor b}^ a current of uniform density, the effective resistance represents the total expenditure of power. Since in an alternating-current circuit, in general power is expended not only in the conductor, but also outside of it, through hysteresis, secondary currents, etc., the effective resist- ance frequently differs from the true ohmic resistance in suc ...Chapter 10: Effective Resistance And Reactance - 173 hit(s)
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CHAPTER X. EFFECTIVE RESISTANCE AND REACTANCE. 72. The resistance of an electric circuit is determined : — 1.) By direct comparison with a known resistance (Wheat- stone bridge method, etc.). This method gives what may be called the true ohmic resistance of the circuit. 2.) By the ratio : Volts consumed in circuit A ...... rk done by the circuit, and the counter E.M.Fs. representing it, as, for instance, in the case of the counter E.M.F. of a motor. In alternating-current circuits, this value of resistance is the energy coefficient of the E.M.F., _ Energy component of E.M.F. Total current It is called the effective resistance of the circuit, since it represents the effect, or power, expended by the circuit. The energy coefficient of current, a._ Energy component of current Total E.M.F. is called the effective conductance of the circuit. EFFECTIVE RESISTANCE AND REACTANCE. 105 In the same way, the value, _ ...Chapter 10: F - 157 hit(s)
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... ork done by the circuit, and the counter E.M.Fs. representing it, as, for instance, in the case of the counter E.M.F. of a motor. In alternating-current circuits, this value of resistance is the energy coefficient of the E.M.F., — Energy compon ent of E.M.F. Total current It is called the effective resistance of the circuit, since it represents the effect, or power, expended by the circuit. The energy coefficient of current, _ Energy component of current ^ Total E.M.F. is called the effective conductance of the circuit. § 733 EFFECTIVE RESISTANCE AND REACTANCE. 105 In the same way, the val ...... t of E.M.F. Total current It is called the effective resistance of the circuit, since it represents the effect, or power, expended by the circuit. The energy coefficient of current, _ Energy component of current ^ Total E.M.F. is called the effective conductance of the circuit. § 733 EFFECTIVE RESISTANCE AND REACTANCE. 105 In the same way, the value, _ Wattless component of E.M.F. Total current is the effective reactance, and , _ Wattless compo nent of current ■" Total E.M.F. is the effective susceptance of the circuit. While the true ohmic resistance represents the expendi- ture of ...Chapter 8: Shaping Of Waves By Magnetic Saturation - 140 hit(s)
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CHAPTER VIII SHAPING OF WAVES BY MAGNETIC SATURATION 66. The wave shapes of current or volt^e produced by a closed magnetic circuit at moderate magnetic densities, such as are com- monly used in transformers and other induction apparatus, have 10 / ^ ^ 8- in.4 /' / -' f / '■ 1 i- 10 / ...CHAPTER VIII SHAPING OF WAVES BY MAGNETIC SATURATION 66. The wave shapes of current or volt^e produced by a closed magnetic circuit at moderate magnetic densities, such as are com- monly used in transformers and other induction apparatus, have 10 / ^ ^ 8- in.4 /' / -' f / '■ 1 i- 10 / 1 / 1 B- n.» / 1 / / / / 1 ' / / y / ...Chapter 4: Magnetism - 139 hit(s)
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CHAPTER IV MAGNETISM Hysteresis 36. Unlike the electric current, which requires power for its maintenance, the maintenance of a magnetic flux does not require energy expenditure (the energy consumed by the magnetizing current in the ohmic resistance of the magnetizing winding being an electrical and not a magne ...CHAPTER IV MAGNETISM Hysteresis 36. Unlike the electric current, which requires power for its maintenance, the maintenance of a magnetic flux does not require energy expenditure (the energy consumed by the magnetizing current in the ohmic resistance of the magnetizing winding being an electrical and not a magnetic effect), ...Chapter 5: Magnetism - 102 hit(s)
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CHAPTER V MAGNETISM Magnetic Constants 47. With the exception of a few ferromagnetic substances, the magnetic permeability of all materials, conductors and dielectrics, gases, liquids and solids, is practically unity for all industrial purposes. Even liquid oxygen, which has the highest permea- bility, differs ...CHAPTER V MAGNETISM Magnetic Constants 47. With the exception of a few ferromagnetic substances, the magnetic permeability of all materials, conductors and dielectrics, gases, liquids and solids, is practically unity for all industrial purposes. Even liquid oxygen, which has the highest permea- bility, differs only by a ...Chapter 25: Distortion Of Wave-Shape And Its Causes - 98 hit(s)
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... wave of impressed e.m.f. a distorting effect will cause distortion of the current wave, while with a sine wave of current passing through the circuit, a dis- torting effect will cause higher harmonics of e.m.f. 233. In a conductor revolving with uniform velocity through a uniform and constant magnetic field, a sine wave of e.m.f. is generated. In a circuit with constant resistance and constant reactance, this sine wave of e.m.f. produces a sine wave of current. Thus distortion of the wave-shape or higher har- monics may be due to lack of uniformity of the velocity of the revolving conductor; lack ...... d. In a circuit with constant resistance and constant reactance, this sine wave of e.m.f. produces a sine wave of current. Thus distortion of the wave-shape or higher har- monics may be due to lack of uniformity of the velocity of the revolving conductor; lack of uniformity or pulsation of the magnetic field; pulsation of the resistance or pulsation of the reactance. 341 342 ALTERNATING-CURRENT PHENOMENA The first two cases, lack of uniformity of the rotation or of the magnetic field, cause higher harmonics of e.m.f. at open circuit. The last, pulsation of resistance and reactance, causes hig ...Chapter 3: Magnetism - 94 hit(s)
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CHAPTER III MAGNETISM Reluctivity 29. Considering magnetism as the phenomena of a "magnetic circuit," the foremost differences between the characteristics of the magnetic circuit and the electric circuit are: (a) The maintenance of an electric circuit requires the ex- penditure of energy, while the maintenance ...CHAPTER III MAGNETISM Reluctivity 29. Considering magnetism as the phenomena of a "magnetic circuit," the foremost differences between the characteristics of the magnetic circuit and the electric circuit are: (a) The maintenance of an electric circuit requires the ex- penditure of energy, while the maintenance of a magnetic circuit does not require th ...Theory Section 1: Magnetism and Electric Current - 93 hit(s)
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1. MAGNETISM AND ELECTRIC CURRENT 1. A magnet pole attracting (or repelling) another magnet pole of equal strength at unit distance with unit force1 is called a unit magnet pole. The space surrounding a magnet pole is called a magnetic field of force, or magnetic fi ...1. MAGNETISM AND ELECTRIC CURRENT 1. A magnet pole attracting (or repelling) another magnet pole of equal strength at unit distance with unit force1 is called a unit magnet pole. The space surrounding a magnet pole is called a magnetic field of force, or magnetic field. The magnetic field at unit distance from a unit magnet pole is called a unit magnetic field, and is represented by one line of magnetic force (or shortly "one line") per square centimeter, and from a unit magnet pole thus i ...Chapter 20: Single-Phase Commutator Motors - 90 hit(s)
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... y low speed, resultant from the low frequency. The direction of rotation of a direct-current motor, whether shunt or series motor, remains the same at a reversal of the im- pressed e.m.f., as in this case the current in the armature circuit and the current in the field circuit and so the field magnetism both reverse. Theoretically, a direct-current motor therefore could be operated on an alternating impressed e.m.f. provided that the magnetic circuit of the motor is laminated, so as to fol- low the alternations of magnetism without serious loss of power, and that precautions are taken to have ...... same at a reversal of the im- pressed e.m.f., as in this case the current in the armature circuit and the current in the field circuit and so the field magnetism both reverse. Theoretically, a direct-current motor therefore could be operated on an alternating impressed e.m.f. provided that the magnetic circuit of the motor is laminated, so as to fol- low the alternations of magnetism without serious loss of power, and that precautions are taken to have the field reverse simul- taneously with the armature. If the reversal of field magnetism should occur later than the reversal of armature curr ...Lecture 2: The Electric Field - 87 hit(s)
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... tric power over line A into a receiving circuit L. While power flows through the conductors A, power is con- sumed in these conductors by conversion into heat, repre- sented by i?r. This, however, Fig. 7. is not all, but in the space surrounding the conductor cer- tain phenomena occur: magnetic and electrostatic forces appear. Fig. 8. — Electric Field of Conductor. The conductor is surrounded by a magnetic field, or a magnetic flux, which is measured by the number of lines of magnetic force <J>. With a single conductor, the lines of magnetic force are concentric circles, as shown ...... in these conductors by conversion into heat, repre- sented by i?r. This, however, Fig. 7. is not all, but in the space surrounding the conductor cer- tain phenomena occur: magnetic and electrostatic forces appear. Fig. 8. — Electric Field of Conductor. The conductor is surrounded by a magnetic field, or a magnetic flux, which is measured by the number of lines of magnetic force <J>. With a single conductor, the lines of magnetic force are concentric circles, as shown in Fig. 8. By the return conductor, the circles 10 THE ELECTRIC FIELD. 11 are crowded together between the conduct ...Chapter 11: Foucault Or Eddy Currents - 86 hit(s)
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CHAPTER XI. FOUCAULT OR EDDY CURRENTS. 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conduct ...CHAPTER XI. FOUCAULT OR EDDY CURRENTS. 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conductor, the mag ...Chapter 16: Induction Motor - 86 hit(s)
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... rce between primary and secondary is used, but not the transfer of electrical energy, and thus the secondary circuits closed upon themselves. Transformer and induction motor thus are the two limiting cases of the general alternating- current transformer. Hence the induction motor consists of a magnetic circuit interlinked with two electric circuits or sets of circuits, the primary and the secondary circuit, which are movable with regard to each other. In general a num- ber of primary and a number of secondary circuits are used, angularly displaced around the periphery of the motor, and conta ...... . In the following discussion, as secondary quantities, the values reduced to the primary system shall be exclusively used, so that, to derive the true secondary values, these quantities have to be reduced backwards again by the factor a = ?*£-. «iA 153. Let $ = total maximum flux of the magnetic field per motor pole, We then have E— V2 77-72 TV^ 10 ~8 = effective E.M.F. induced by the mag- netic field per primary circuit. Counting the time from the moment where the rising magnetic flux of mutual induction & (flux interlinked with both electric circuits, primary and secondary) passes thro ...Chapter 6: Alternating Magnetic Flux Distribution - 85 hit(s)
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CHAPTER VI. ALTERNATING MAGNETIC FLUX DISTRIBUTION. 48. As carrier of magnetic flux iron is used, as far as possible, since it has the highest permeability or magnetic conductivity. If the magnetic flux is alternating or otherwise changing rapidly, an e.m.f. is generated by the change of magnetic flux in the iron, and to avoid en ...CHAPTER VI. ALTERNATING MAGNETIC FLUX DISTRIBUTION. 48. As carrier of magnetic flux iron is used, as far as possible, since it has the highest permeability or magnetic conductivity. If the magnetic flux is alternating or otherwise changing rapidly, an e.m.f. is generated by the change of magnetic flux in the iron, and to avoid energy losses and demagnetization by the currents ...Lecture 2: The Electric Field - 84 hit(s)
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... ic power over line A into a receiving circuit M. While power flows through the conductors A, power is con- sumed in these conductors by JV[ conversion into heat, repre- sented by ^2r. This, however, Fig. 7. is not all, but in the space surrounding the conductor cer- tain phenomena occur: magnetic and electrostatic forces appear. Fig. 8. — Electric Field of Conductor. The conductor is surrounded by a magnetic field, or a magnetic flux, which is measured by the number of lines of magnetic force $. With a single conductor, the lines of magnetic force are concentric circles, as shown i ...... these conductors by JV[ conversion into heat, repre- sented by ^2r. This, however, Fig. 7. is not all, but in the space surrounding the conductor cer- tain phenomena occur: magnetic and electrostatic forces appear. Fig. 8. — Electric Field of Conductor. The conductor is surrounded by a magnetic field, or a magnetic flux, which is measured by the number of lines of magnetic force $. With a single conductor, the lines of magnetic force are concentric circles, as shown in Fig. 8. By the return conductor, the circles 10 THE ELECTRIC FIELD. 11 are crowded together between the conductor ...Chapter 11: Fouoault Or Eddy 0Ubbent8 - 80 hit(s)
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CHAPTER XI. FOUOAULT OR EDDY 0UBBENT8. • 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conduct ...CHAPTER XI. FOUOAULT OR EDDY 0UBBENT8. • 86. While magnetic hysteresis or molecular friction is a magnetic phenomenon, eddy currents are rather an elec- trical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conductor, the mag ...Chapter 12: Magnetic Saturation And Hysteresis In Alternat Ing-Current Circuits - 80 hit(s)
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CHAPTER XII. MAGNETIC SATURATION AND HYSTERESIS IN ALTERNAT- ING-CURRENT CIRCUITS. 99. If an alternating e.m.f. is impressed upon a circuit con- taining resistance and inductance, the current and thereby the magnetic flux produced by the current immediately assume their final or permanent values only in case the c ...CHAPTER XII. MAGNETIC SATURATION AND HYSTERESIS IN ALTERNAT- ING-CURRENT CIRCUITS. 99. If an alternating e.m.f. is impressed upon a circuit con- taining resistance and inductance, the current and thereby the magnetic flux produced by the current immediately assume their final or permanent values only in case the circuit is closed at that ...Chapter 18: Oscillating Currents - 69 hit(s)
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... oscillating currents, resist- ance as well as conductance have a negative term added, which depends on the decrement a. Such a negative resistance repre- sents energy production, and its meaning in the present case is, that with the decrease of the oscillating current and voltage, their stored magnetic and dielectric energy become available. Circuits of Zero Impedance 190. In an oscillating-current circuit of decrement, a, of resistance, r, inductive reactance, x, and condensive reactance, Xc, the impedance was represented in symbolic expression by or numerically by z = Vr"7T^ = yj{r-ax ...... = 2 x/L, 1 a = 2t/= *■ 2oL' we have _ r _ r 14 L hence, by substitution, / = — je -J J- dec a, ^, = — jer yjj- dec a, a = the final equations of the oscillating discharge, in symbolic ex- pression. 23 INDEX Admittance, with oscillating cur- rents, 348 Air gap in magnetic circuit reducing wave distortion, 145 Alloys, resistance, 2 Alternating component of power of general system, 317 current electromagnet, 95 magnetic characteristic, 51 Alternations by capacity inductance shunt to arc, 187 Aluminum cell as condenser, 10 Amorphous carbon resistance, 23 A ...Theory Section 10: Hysteresis and Effective Resistance - 65 hit(s)
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10. HYSTERESIS AND EFFECTIVE RESISTANCE 46. If an alternating current 01 = I, in Fig. 21, exists in a circuit of reactance x = 2 irfL and of negligible resistance, the HYSTERESIS AND EFFECTIVE RESISTANCE 49 magnetic flux produced by the current, 0$ = $, is in ...10. HYSTERESIS AND EFFECTIVE RESISTANCE 46. If an alternating current 01 = I, in Fig. 21, exists in a circuit of reactance x = 2 irfL and of negligible resistance, the HYSTERESIS AND EFFECTIVE RESISTANCE 49 magnetic flux produced by the current, 0$ = $, is in phase with the current, ...Chapter 10: Hysteresis Motor - 65 hit(s)
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CHAPTER X HYSTERESIS MOTOR 98. In it revolving magnetic field, a circular iron disk, or iron cylinder of uniform magnetic reluctance in the direction of the revolving field, is set in rotation, even if subdivided so as to preclude the production of eddy currents. Thin rotation is due to the effect of hysteresis of the ...CHAPTER X HYSTERESIS MOTOR 98. In it revolving magnetic field, a circular iron disk, or iron cylinder of uniform magnetic reluctance in the direction of the revolving field, is set in rotation, even if subdivided so as to preclude the production of eddy currents. Thin rotation is due to the effect of hysteresis of the revolving disk or cylinder, and such ...Chapter 16: Reaction Machines - 65 hit(s)
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... made that the reactance, x, of the machine is a constant. While this is more or less approximately the case in many alternators, in others, especially in machines of large armature reaction, the reactance, x, is variable, and is different in the different positions of the armature coils in the magnetic circuit. This variation of the reactance causes phenomena which do not find their explanation by the theoretical calculations made under the assumption of constant reactance. It is known that synchronous motors or converters of large and variable reactance keep in synchronism, and are able to ...... the e.m.f. of a generator do not disappear if the generator field circuit is broken, or even reversed to a small negative value, in which tatter case the current is against the e.m.f., Ea, of the generator. Furthermore, a shuttle armature without any winding (Fig. 120) will in an alternating magnetic field revolve when once brought up to synchronism, and do considerable work as a motor. These phenomena are not due to remanent magnetism nor to the magnetizing effect of eddy currents, because they exist also in machines with laminated fields, and exist if the alternator is brought up to synchroni ...Chapter 17: Inductor Machines - 61 hit(s)
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... INDUCTOR MACHINES Inductor Alternators, Etc. 156. Synchronous machines may be built with stationary field and revolving armature, as shown diagrammatically in Fig. 134, or with revolving field and stationary armature, Fig. 135, or with stationary field and stationary armature, but revolving magnetic circuit. The revolving-armature type was the most frequent in the early days, but has practically gone out of use except for special Fia. 134. — Revolving armature alternator Fig. 135.— Revolving field al ternator. purposes, and for synchronous commutating machines, as the revolving- ...... cies and other special conditions, and in this field, its use is rapidly increasing. A typical inductor alternator is shown in Fig. 136. as eight- polar quarter-phase machine. 274 INDUCTOR MACHINES 275 Its armature coils, A, are stationary. One stationary field coil, F, surrounds the magnetic circuit of the machine, which consists of two sections, the stationary external one, B, which contains the armature, A, and a movable one, C, which contains the inductor, N. The inductor contains as many polar projec- tions, N, as there are cycles or pairs of poles. The magnetic flux in the ai ...Chapter 7: Distribution Of Alternating-Current Density In Conductor - 59 hit(s)
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CHAPTER VII. DISTRIBUTION OF ALTERNATING-CURRENT DENSITY IN CONDUCTOR. 59. If the frequency of an alternating or oscillating current is high, or the section of the conductor which carries the current is very large, or its electric conductivity or its magnetic per- meability high, the current density is not uniform throughout the conductor section, but decreases towards the interior of the conductor, due to the higher e.m.f. of self-inductance in the interior of the conductor, caused by the magnetic flux inside of the conductor. The phase of the cur ...... is very large, or its electric conductivity or its magnetic per- meability high, the current density is not uniform throughout the conductor section, but decreases towards the interior of the conductor, due to the higher e.m.f. of self-inductance in the interior of the conductor, caused by the magnetic flux inside of the conductor. The phase of the current inside of the conductor also differs from that on the surface and lags behind it. In consequence of this unequal current distribution in a large conductor traversed by ^alternating currents, the effective resist- ance of the conductor may be f ...Chapter 12: Reactance Of Induction Apparatus - 58 hit(s)
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CHAPTER XII REACTANCE OF INDUCTION APPARATUS 109. An electric current passing through a conductor is ac- companied by a magnetic field surrounding this conductor, and this magnetic field is as integral a part of the phenomenon, as is the energy dissipation by the resistance of the conductor. It is represented by the inductance, L, of the conductor, or the number of magnetic interlinkages with unit current in the conductor. Ev ...CHAPTER XII REACTANCE OF INDUCTION APPARATUS 109. An electric current passing through a conductor is ac- companied by a magnetic field surrounding this conductor, and this magnetic field is as integral a part of the phenomenon, as is the energy dissipation by the resistance of the conductor. It is represented by the inductance, L, of the conductor, or the number of magnetic interlinkages with unit current in the conductor. Every circuit thus has a resistance, and an inductance, ...Chapter 13: Foucault Or Eddy Currents - 57 hit(s)
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CHAPTER XIII FOUCAULT OR EDDY CURRENTS 105. While magnetic hysteresis due to molecular friction is a magnetic phenomenon, eddy currents are rather an electrical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric condu ...CHAPTER XIII FOUCAULT OR EDDY CURRENTS 105. While magnetic hysteresis due to molecular friction is a magnetic phenomenon, eddy currents are rather an electrical phenomenon. When iron passes through a magnetic field, a loss of energy is caused by hysteresis, which loss, however, does not react magnetically upon the field. When cutting an electric conductor, the m ...Chapter 17: The Alternating-Current Transformer - 55 hit(s)
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CHAPTER XVII THE ALTERNATING-CURRENT TRANSFORMER 141. The simplest alternating-current apparatus is the trans- former. It consists of a magnetic circuit interlinked with two electric circuits, a primary and a secondary. The primary circuit is excited by an impressed e.m.f., while in the secondary circuit an e.m.f. is generated. Thus, in the primary circuit power is consumed, and in the secondary a corresponding amount of power is produ ...... ith two electric circuits, a primary and a secondary. The primary circuit is excited by an impressed e.m.f., while in the secondary circuit an e.m.f. is generated. Thus, in the primary circuit power is consumed, and in the secondary a corresponding amount of power is produced. Since the same magnetic circuit is interlinked with both electric circuits, the e.m.f. generated per turn must be the same in the secondary as in the primary circuit; hence, the primary generated e.m.f. being approximately equal to the impressed e.m.f., the e.m.fs. at primary and at secondary terminals have approxima ...Chapter 6: Magnetism - 55 hit(s)
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CHAPTER VI MAGNETISM MECHANICAL FORCES 1. General 61. Mechanical forces appear wherever magnetic fields act on electric currents. The work done by all electric motors is the result of these forces. In electric generators, they oppose the driving power and thereby consume the power which finds its equivalent i ...CHAPTER VI MAGNETISM MECHANICAL FORCES 1. General 61. Mechanical forces appear wherever magnetic fields act on electric currents. The work done by all electric motors is the result of these forces. In electric generators, they oppose the driving power and thereby consume the power which finds its equivalent in the electric power output. The motions produced by the electromagnet are due to ...Chapter 1: The Constants Of The Electric Circuit - 54 hit(s)
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... tic of the direc- tion of the flow of energy.) In the space outside of the conductor, during the flow of energy through the circuit, a condition of stress exists which is called the electric field of the conductor. That is, the surrounding space is not uniform, but has different electric and magnetic properties in different directions. No power is required to maintain the electric field, but energy 3 4 TRANSIENT PHENOMENA is required to produce the electric field, and this energy is returned, more or less completely, when the electric field dis- appears by the stoppage of the flow of ...... ed. As result hereof, where the flow of electric energy pulsates, as in an alternating- current circuit, continuously electric energy is stored in the field during a rise of the power, and returned to the circuit again during a decrease of the power. The electric field of the conductor exerts magnetic and elec- trostatic actions. The magnetic action is a maximum in the direction concen- tric, or approximately so, to the conductor. That is, a needle- shaped magnetizable body, as an iron needle, tends to set itself in a direction concentric to the conductor. The electrostatic action has a ...Lecture 10: Continual And Cumulative Oscillations - 53 hit(s)
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... ULATIVE OSCILLATIONS. 43. A transient is the phenomenon by which the stored energy readjusts itself to a change of circuit conditions. In an oscilla- tory transient, the difference of stored energy of the previous and the after condition of the circuit, at a circuit change, oscillates between magnetic and dielectric energy. As there always must be some energy dissipation in the circuit, the oscillating energy of the transient must steadily decline, that is, the transient must die out, at a rate depending on the energy dissipation in the cir- cuit. Thus, the oscillation resulting from a cha ...... d period occurs, during which the energy, which oscillates during the next wave train, is supplied to the line, this energy must be supplied during the oscillation, that is, there must be such a phase displacement or lag within the oscil- lation, which gives a negative energy cycle, or reversed hysteresis loop. Thus, essential for such a continual oscillation is the 124 ELECTRICAL DISCHARGES, WAVES AND IMPULSES existence of a hysteresis loop, formed by the lag of the effect be- hind the cause. Such a hysteresis loop exists in the transient arc, as illustrated by Fig. 66: the transient volt-a ...Chapter 22: Armature Reactions Of Alternators - 51 hit(s)
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... e of load at constant field excitation, is due to the combined effect of armature reaction and armature self-induction. The counter m.m.f. of the armature current, or armature reaction, combines with the impressed m.m.f. or field excitation to the resultant m.m.f., which produces the resultant magnetic field in the field poles and generates in the armature an e.m.f. called the "virtual generated e.m.f.," since it has no actual existence, but is merely a mathematical fiction. The counter e.m.f. of self-induction of the armature current, that is, e.m.f. generated by the armature current by a local m ...... d in the field poles and generates in the armature an e.m.f. called the "virtual generated e.m.f.," since it has no actual existence, but is merely a mathematical fiction. The counter e.m.f. of self-induction of the armature current, that is, e.m.f. generated by the armature current by a local magnetic flux, combines with the virtual generated e.m.f. to the actual generated e.m.f. of the armature, which corresponds to the magnetic flux in the armature core. This combined with the e.m.f. consumed by the armature resist- ance gives the terminal voltage. In most cases the effect of armature reactio ...