Reactance, Impedance, And Admittance Evidence
Reactance, Impedance, And Admittance
Section titled “Reactance, Impedance, And Admittance”Evidence status: generated from processed OCR/PDF text. Treat each hit as a source-location aid until the passage is checked against the scan.
8318 hits
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14 sources
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293 sections
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What This Theme Gathers
Section titled “What This Theme Gathers”Passages involving reactance, impedance, admittance, conductance, susceptance, wattless components, counter e.m.f., and phasor opposition language.
Reading Layers
Section titled “Reading Layers”Source Evidence
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Modern Reading Prompt
Use these passages to preserve Steinmetz’s transition from geometric/vector reasoning into impedance and admittance language.
Interpretive Boundary
Field-pressure or inertia language may be useful as an analogy, but impedance and admittance claims must remain anchored in the circuit mathematics Steinmetz gives.
Matched Aliases
Section titled “Matched Aliases”| Alias | Hits |
|---|---|
resistance | 2796 |
reactance | 2152 |
impedance | 1214 |
quadrature | 567 |
admittance | 456 |
counter e.m.f. | 321 |
inductive reactance | 308 |
conductance | 302 |
wattless | 299 |
susceptance | 210 |
condensive reactance | 120 |
counter electromotive force | 1 |
counter-electromotive force | 1 |
Source Distribution
Section titled “Source Distribution”Section Hits
Section titled “Section Hits”Representative Source-Located Passages
Section titled “Representative Source-Located Passages”Chapter 14: Constant-Potential Constant-Current Trans Formation - 228 hit(s)
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... nt or variable inductive reactances, and may be produced by the combination of inductive and condensive reactances; and the investigation of different methods of producing constant alternating current from constant alternating voltage, or inversely, constitutes a good application of the terms "impedance," admittance," etc., and offers a large number of problems or examples for the symbolic method of dealing with alternating-current phenomena. Even outside of arc lighting, such combinations of inductance and capacity which t«nd toward constant-voltage constant-cur- rent transformation are of ...... le inductive reactances, and may be produced by the combination of inductive and condensive reactances; and the investigation of different methods of producing constant alternating current from constant alternating voltage, or inversely, constitutes a good application of the terms "impedance," admittance," etc., and offers a large number of problems or examples for the symbolic method of dealing with alternating-current phenomena. Even outside of arc lighting, such combinations of inductance and capacity which t«nd toward constant-voltage constant-cur- rent transformation are of considerable ...Chapter 20: Single-Phase Commutator Motors - 195 hit(s)
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... ossessed by the direct-current motor. While in its general principle of operation the alternating- current commutator motor is identical with the direct-cums! motor, in the relative proportioning of the parts a great differ- ence exists. In the direct-current motor, voltage is consumed by the counter e.m.f. of rotation, which represents the power output of the motor, and by the resistance, which represents the power loss. In addition thereto, in the alternating-cur rent motor voltage is consumed by the inductance, which is wattless or reactive and therefore causes a lag of current behind the vol- ...... alternating- current commutator motor is identical with the direct-cums! motor, in the relative proportioning of the parts a great differ- ence exists. In the direct-current motor, voltage is consumed by the counter e.m.f. of rotation, which represents the power output of the motor, and by the resistance, which represents the power loss. In addition thereto, in the alternating-cur rent motor voltage is consumed by the inductance, which is wattless or reactive and therefore causes a lag of current behind the vol- tage, that is, a lowering of the power-factor. While in the direct- current motor ...Chapter 16: Induction Motor - 160 hit(s)
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... the ratio of transformation, a ; thus INDUCTION MOTOR. 239 if E{ = secondary E.M.F. per circuit, El = aE{ = secondary E.M.F. per circuit reduced to primary system; if // = secondary current per circuit, fl= — = secondary current per circuit reduced to primary system ; if r^ = secondary resistance per circuit, rt = a2 r{ = secondary resistance per circuit reduced to primary system ; if x± = secondary reactance per circuit, xt = a2 x\ = secondary reactance per circuit reduced to primary system ; if £/ = secondary impedance per circuit, z1 = azz\ = secondary impedance per circuit reduc ...... ON MOTOR. 239 if E{ = secondary E.M.F. per circuit, El = aE{ = secondary E.M.F. per circuit reduced to primary system; if // = secondary current per circuit, fl= — = secondary current per circuit reduced to primary system ; if r^ = secondary resistance per circuit, rt = a2 r{ = secondary resistance per circuit reduced to primary system ; if x± = secondary reactance per circuit, xt = a2 x\ = secondary reactance per circuit reduced to primary system ; if £/ = secondary impedance per circuit, z1 = azz\ = secondary impedance per circuit reduced to primary system ; that is, the number of s ...Chapter 5: Single-Phase Induction Motor - 126 hit(s)
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... h their maxi- mum in the position (1 — s) ~ = 90 (1 — s) electrical degrees behind the direction of the main magnetic flux. A component of the armature currents then magnetizes in the direction at right angles (electrically) to the main magnetic flux, and the armature currents thus produce a quadrature magnetic flux, increasing from zero at standstill, to a maximum at synchronism, and approximately proportional to the quadrature component of the armature polarization, P: P sin (1 — s) • 93 ill ELECTRICAL APPARATUS The torque of the single-phase motor then is produced by the action ...... omponent of the armature currents then magnetizes in the direction at right angles (electrically) to the main magnetic flux, and the armature currents thus produce a quadrature magnetic flux, increasing from zero at standstill, to a maximum at synchronism, and approximately proportional to the quadrature component of the armature polarization, P: P sin (1 — s) • 93 ill ELECTRICAL APPARATUS The torque of the single-phase motor then is produced by the action of the quadrature flux on the energy currents induced by the main flux, and thus is proportional to the quadrature flux. At syn ...Chapter 9: Circuits Containing Resistance, Inductive Reactance, And Condensive Reactance - 117 hit(s)
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CHAPTER IX CIRCUITS CONTAINING RESISTANCE, INDUCTIVE REACTANCE, AND CONDENSIVE REACTANCE 53. Having, in the foregoing, re-established Ohm's law and Kirchhoff 's laws as being also the fundamental laws of alternating- current circuits, when expressed in their complex form, E = ZI, or, 7 = YE, and "EE = 0 in a closed circuit, S/ ...CHAPTER IX CIRCUITS CONTAINING RESISTANCE, INDUCTIVE REACTANCE, AND CONDENSIVE REACTANCE 53. Having, in the foregoing, re-established Ohm's law and Kirchhoff 's laws as being also the fundamental laws of alternating- current circuits, when expressed in their complex form, E = ZI, or, 7 = YE, and "EE = 0 in a closed circuit, S/ = 0 at a distributing ...Chapter 12: Effective Resistance And Reactance - 112 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 ...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 Amperes in circuit ...Chapter 10: Effective Resistance And Reactance - 110 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 ...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 Amperes in circ ...Chapter 8: Admittance, Conductance, Susceptance - 109 hit(s)
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CHAPTER VIII ADMITTANCE, CONDUCTANCE, SUSCEPTANCE 48. If in a continuous-current circuit, a number of resistances, Ti, r2, ?'3, . . ., are connected in series, their joint resistance, R, is the sum of the individual resistances, K = ri + r2 + ra + . . . If, however, a number of resistances are connected in multiple ...CHAPTER VIII ADMITTANCE, CONDUCTANCE, SUSCEPTANCE 48. If in a continuous-current circuit, a number of resistances, Ti, r2, ?'3, . . ., are connected in series, their joint resistance, R, is the sum of the individual resistances, K = ri + r2 + ra + . . . If, however, a number of resistances are connected in multiple or in parall ...Chapter 10: Resistance And Reactance Of Transmission - 107 hit(s)
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CHAPTER X RESISTANCE AND REACTANCE OF TRANSMISSION LINES 65. In alternating-current circuits, voltage is consumed in the feeders of distributing networks, and in the lines of long- distance transmissions, not only by the resistance, but also by the reactance, of the line. The voltage consumed by the resistance ...CHAPTER X RESISTANCE AND REACTANCE OF TRANSMISSION LINES 65. In alternating-current circuits, voltage is consumed in the feeders of distributing networks, and in the lines of long- distance transmissions, not only by the resistance, but also by the reactance, of the line. The voltage consumed by the resistance is in phase, w ...Chapter 4: Induction Motor With Secondary Excitation - 105 hit(s)
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... he magnetic field is excited by a direct current, characteristic of the induction machine is, that the magnetic field is excited by an alternating current derived from the alter- nating supply voltage, just as in the alternating-current trans- former. As the alternating magnetizing current is a wattless reactive current, the result is, that the alternating-current input into the induction motor is always lagging, the more so, the larger a part of the total current is given by the magnetizing current. To secure good power-factor in an induction motor, the magnetizing current, that i«, the curr ...... may nevertheless be secured, power-factor and apparent efficiency necessarily are very low. As illustration is shown in Fig. 20 the load curve of a typical 100-hp. 60-cycle 80-polar induction motor (90 revolutions per minute) of the constants: Impressed voltage: ea = 500. Primary exciting admittance: Ya = 0.02 — 0.6 j. Primary self-inductive impedance: Zu = 0.1 + 0.3j. Secondary self-inductive impedance: Zi = 0.1 + 0.3 j. INDUCTION MOTOR 53 As seen, at full-load of 75 kw. output, the efficiency is 80 per cent., which is fair for a slow-speed motor. But the power-factor is 55 pe ...Chapter 10: F - 103 hit(s)
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CHAPTER X. f EFFECnVH BSSISTANCi: Ain> BJEACTANOB. 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 circu it Amperes in circuit In an alternatin ...CHAPTER X. f EFFECnVH BSSISTANCi: Ain> BJEACTANOB. 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 circu it Amperes in circuit In an alternating-current circuit, this method gives, not the resistance of the circuit, but the impedance, ...Chapter 7: Admittance, Conductance, Susceptance - 103 hit(s)
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CHAPTER VII. ADMITTANCE, CONDUCTANCE, SUSCEPTANCE. 38. If in a continuous-current circuit, a number of resistances, ?\, r%, r3, . . . are connected in series, their joint resistance, R, is the sum of the individual resistances If, however, a number of resistances are connected in multiple or in parallel, their join ...CHAPTER VII. ADMITTANCE, CONDUCTANCE, SUSCEPTANCE. 38. If in a continuous-current circuit, a number of resistances, ?\, r%, r3, . . . are connected in series, their joint resistance, R, is the sum of the individual resistances If, however, a number of resistances are connected in multiple or in parallel, their joint resistance, ...Chapter 1: Speed Control Of Induction Motors - 103 hit(s)
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... till, the torque of the motor is low and the current high, that is, the starting-torque efficiency and especially the apparent starting-torque efficiency are low. Where starting with considerable load, and without excessive current, is necessary, the induction motor thus requires the use of a resistance in the armature or secondary, just as the direct- current shunt motor, and this resistance must be a rheostat, that is, variable, so as to have maximum resistance in starting, and gradually, or at least in a number of successive steps, cut out the resistance during acceleration. This, however ...... iciency and especially the apparent starting-torque efficiency are low. Where starting with considerable load, and without excessive current, is necessary, the induction motor thus requires the use of a resistance in the armature or secondary, just as the direct- current shunt motor, and this resistance must be a rheostat, that is, variable, so as to have maximum resistance in starting, and gradually, or at least in a number of successive steps, cut out the resistance during acceleration. This, however, requires a wound secondary, and the squirrel- cage type of rotor, which is the simplest, ...Chapter 7: Admittance, Conductance, Susceftance - 101 hit(s)
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CHAPTER VII. ADMITTANCE, CONDUCTANCE, SUSCEFTANCE. 38. If in a continuous-current circuit, a number of resistances, rj, rj, rg, . . . are connected in series, their joint resistance, Ry is the sum of the individual resistances ^ = ^1 + ^2 + 'a + • • • If, however, a number of resistances are connected in multip ...CHAPTER VII. ADMITTANCE, CONDUCTANCE, SUSCEFTANCE. 38. If in a continuous-current circuit, a number of resistances, rj, rj, rg, . . . are connected in series, their joint resistance, Ry is the sum of the individual resistances ^ = ^1 + ^2 + 'a + • • • If, however, a number of resistances are connected in multiple or in para ...Chapter 9: Resistance And Reactance Of Transmission Lines - 99 hit(s)
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CHAPTER IX. RESISTANCE AND REACTANCE OF TRANSMISSION LINES. 57. In alternating-current circuits, E.M.F. is consumed in the feeders of distributing networks, and in the lines of long-distance transmissions, not only by the resistance, but also by the reactance, of the line. The E.M.F. consumed by the resistance is i ...CHAPTER IX. RESISTANCE AND REACTANCE OF TRANSMISSION LINES. 57. In alternating-current circuits, E.M.F. is consumed in the feeders of distributing networks, and in the lines of long-distance transmissions, not only by the resistance, but also by the reactance, of the line. The E.M.F. consumed by the resistance is in phase, while ...Chapter 10: Instability Of Circuits : The Arc - 97 hit(s)
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... he oscillograms. Figs. 80 and 81. Somewhat similar effects of instability are produced by pyro- electric conductors. Induction motors and synchronous motors may show instability of speed: dropping out of step, etc. III. Permanent instability 86. If the constants of an electric circuit, as resistance, in- ductance, capacity, disruptive strength, voltage, speed, etc., have values, which can not coexist, the circuit is unstable, and remains so as long as these constants remain unchanged. Case (3) of II, imstable equilibrium, to some extent may be considered as belonging in this class. The ...... tt \ Q ^ U- ■?>- ^ k^ / _ , / ^ / F -^ — — i_ ^ 5 2. 3. G L i. G EL G chapter on "Electric Conductors." As shown there, the arc is always unstable on constant voltage impressed upon it. Series 168 ELECTRIC CIRCUITS resistance or reactance produces stability for currents above a certain critical value of current, io. Such curves, giving the vol- tage consumed by the arc and its series resistance as function of the current, thus may be termed stability curves of the arc. Their minimum values, that is, the stability li ...Chapter 17: The Alternating-Current Transformer - 96 hit(s)
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... oil only, without being interlinked with the other. This magnetic cross-flux is proportional to the current in the electric circuit, or rather, the ampere-turns or m.m.f., and so increases with the increasing load on the transformer, and constitutes what is called the self-inductive or leakage reactance of the trans- former; while the flux surrounding both coils may be con- sidered as mutual inductive reactance. This cross-flux of self-induction does not generate e.m.f. in the secondary circuit, 187 188 ALTERNATING-CURRENT PHENOMENA and is thus, in general, objectionable, by causing a dr ...... current in the electric circuit, or rather, the ampere-turns or m.m.f., and so increases with the increasing load on the transformer, and constitutes what is called the self-inductive or leakage reactance of the trans- former; while the flux surrounding both coils may be con- sidered as mutual inductive reactance. This cross-flux of self-induction does not generate e.m.f. in the secondary circuit, 187 188 ALTERNATING-CURRENT PHENOMENA and is thus, in general, objectionable, by causing a drop of voltage and a decrease of output. It is this cross-flux, how- ever, or flux of self-inductive reactance, ...Apparatus Section 3: Induction Machines: Single -phase Induction Motor - 95 hit(s)
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... no work whatever, the secondary becomes current- less, and the primary current is the exciting current of the motor only. In the single-phase induction motor, even when running light, the secondary still carries the exciting current of the mag- netic flux in quadrature with the axis of the primary exciting coil. Since, this flux has essentially the same intensity as the flux in the direction of the axis of the primary exciting coil, the current in the armature of the single-phase induction motor run- ning light, and the ...... it is the exciting current of the main magnetic flux plus the current producing in the secondary the exciting current of the cross magnetic flux. In reality it is slightly less, especially in small motors, due to the drop of voltage in the self-inductive impedance and the drop of quadrature mag- netic flux below the impressed primary magnetic flux caused thereby. In the secondary at synchronism this secondary exciting current is a current of twice the primary frequency; at any other speed it is of a frequency equal ...Chapter 8: Circuits Containing Resistance, Inductance, And Capacity - 95 hit(s)
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CHAPTER VIII. CIRCUITS CONTAINING RESISTANCE, INDUCTANCE, AND CAPACITY. 42. Having, in the foregoing, reestablished Ohm's law and Kirchhoff's laws as being also the fundamental laws of alternating-current circuits, when expressed in their com- plex form, E = ZS, or, / = YE, and *%E = 0 in a closed circuit, S/ = 0 at a distributing ...... ished Ohm's law and Kirchhoff's laws as being also the fundamental laws of alternating-current circuits, when expressed in their com- plex form, E = ZS, or, / = YE, and *%E = 0 in a closed circuit, S/ = 0 at a distributing point, where E, I, Z, Y, are the expressions of E.M.F., current, impedance, and admittance in complex quantities, — these values representing not only the intensity, but also the phase, of the alternating wave, — we can now — by application of these laws, and in the same manner as with continuous- current circuits, keeping in mind, however, that E, I, Z, Y, are compl ...Mathematical Appendix 5: Appendix: Synchronous Operation - 94 hit(s)
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... by: ei = E cos (0 co) 1 e2 = Ecos (0+co) / (1) and the resultant voltage in the circuit between the alternators then is : e = ei e 2 = E cos \ (<f> co) cos (</>+ co) [ = 2E sin co sin (2) and the interchange currentwbeteen the alternators is: 2E . i = sin co sin (<j> a) (3) where: z = r2+x 2 is the impedance of the circuit between the two alternators, and the phase angle a is given by: x tan a = - r and: r= resistance x = reactance of the circuit between the alternators (including their internal resistances and reactances). [[END_PDF_PAGE:28]] [[PDF_PAGE:29]] Report of Charles P. Steinmetz 23 The powe ...... then is : e = ei e 2 = E cos \ (<f> co) cos (</>+ co) [ = 2E sin co sin (2) and the interchange currentwbeteen the alternators is: 2E . i = sin co sin (<j> a) (3) where: z = r2+x 2 is the impedance of the circuit between the two alternators, and the phase angle a is given by: x tan a = - r and: r= resistance x = reactance of the circuit between the alternators (including their internal resistances and reactances). [[END_PDF_PAGE:28]] [[PDF_PAGE:29]] Report of Charles P. Steinmetz 23 The power of one of the two alternators then is given by: 2E 2 = sin co sin (d> a) cos (<f> co) z E 2 f 1 = sin co sin { ...Chapter 9: Kbsistanci: And Kbactance Of Transmission Iine8 - 90 hit(s)
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CHAPTER IX. KBSISTANCi: AND KBACTANCE OF TRANSMISSION IINE8. 57. In alternating-current circuits, E.M.F. is consumed in the feeders of distributing networks, and in the lines of long-distance transmissions, not only by the resistance, but also by the reactance, of the line. The E.M.F. consumed by the resistance is in phase, while the E.M.F. consumed by the reactance is in quadrature, with the current. Hence their influence upon the E.M.F. at the receiver circuit depends upon the difference of phase between the current and ...CHAPTER IX. KBSISTANCi: AND KBACTANCE OF TRANSMISSION IINE8. 57. In alternating-current circuits, E.M.F. is consumed in the feeders of distributing networks, and in the lines of long-distance transmissions, not only by the resistance, but also by the reactance, of the line. The E.M.F. consumed by the resistance is in phase, while the E.M.F. consumed by the reactance is in quadrature, with the current. Hence their influence upon the E.M.F. at the receiver circuit depends upon the difference of phase between the current and the E.M.F. in that circuit. ...Chapter 24: Synchronous Motor - 89 hit(s)
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... e made use mostly of the sym- bolic method, we may in the following, as an example of the graphical method, treat the action of the synchronous motor graphically. Let an alternator of the e.m.f., Ei, be connected as synchron- ous motor with a supply circuit of e.m.f., Eo, by a circuit of the impedance, Z. If £"0 is the e.m.f. impressed upon the motor terminals, Z is the impedance of the motor of generated e.m.f., Ei. If Eq is the e.m.f. at the generator terminals, Z is the impedance of motor and line, including transformers and other intermediate apparatus. If Eq is the generated e.m.f. of ...... of the graphical method, treat the action of the synchronous motor graphically. Let an alternator of the e.m.f., Ei, be connected as synchron- ous motor with a supply circuit of e.m.f., Eo, by a circuit of the impedance, Z. If £"0 is the e.m.f. impressed upon the motor terminals, Z is the impedance of the motor of generated e.m.f., Ei. If Eq is the e.m.f. at the generator terminals, Z is the impedance of motor and line, including transformers and other intermediate apparatus. If Eq is the generated e.m.f. of the generator, Z is the sum of the impedances of motor, line, and generator, and ...Chapter 12: Reactance Of Induction Apparatus - 89 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 t ...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, however small the latter may be in the so-called "non-inductive" circuit. With continu ...Chapter 9: High-Frequency Conductors - 88 hit(s)
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... receding chapters, conductors intended to convey currents of very high frequency, as lightning discharges, high frequency oscillations of transmission lines, the currents used in wireless telegraphy, etc., cannot be calculated by the use of the constants derived at low frequency, but effective resistance and inductance, and therewith the power consumed by the conductor, and the voltage drop, may be of an entirely different magnitude from the values which would be found by using the usual values of resistance and induc- tance. In conductors such as are used in the connections and the discharge ...... annot be calculated by the use of the constants derived at low frequency, but effective resistance and inductance, and therewith the power consumed by the conductor, and the voltage drop, may be of an entirely different magnitude from the values which would be found by using the usual values of resistance and induc- tance. In conductors such as are used in the connections and the discharge path of lightning arresters and surge protectors, the unequal current distribution in the conductor (Chapter VII) and the power and voltage consumed by electric radiation, due to the finite velocity of the el ...Chapter 20: Single-Phase Induction Motors - 87 hit(s)
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CHAPTER XX SINGLE-PHASE INDUCTION MOTORS 177. The magnetic circuit of the induction motor at or near synchronism consists of two magnetic fluxes superimposed upon each other in quadrature, in time, and in position. In the polyphase motor these fluxes are produced by e.m.fs. displaced in phase. In the monocyclic motor one of the fluxes is due to the primary power circuit, the other to the primary exciting circuit. In the single-phase motor the one flux is produced by the primary ...... in phase. In the monocyclic motor one of the fluxes is due to the primary power circuit, the other to the primary exciting circuit. In the single-phase motor the one flux is produced by the primary circuit, the other by the currents produced in the secondary or armature, which are carried into quadrature posi- tion by the rotation of the armature. In consequence thereof, while in all these motors the magnetic distribution is the same at or near synchronism, and can be represented by a rotating field of uniform intensity and uniform velocity, it remains such in polyphase and monocyclic motors; ...Chapter 22: Armature Reactions Of Alternators - 86 hit(s)
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... bines 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 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 ...... ntracted in one constant; for purposes of design, frequently the self-induction is represented by an increase of the armature reaction, that is, an effective armature reaction used which com- bines the effect of the true armature reaction and the armature self-induction. That is, instead of the counter e.m.f. of self- induction, a counter m.m.f. is used, which would produce the magnetic flux which would generate the e.m.f. of self-induction. For theoretical investigations usually the armature reaction is represented by an effective self-induction, that is, instead of the counter m.m.f. of the arma ...Chapter 18: Polyphase Induction Motors - 83 hit(s)
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... ation, a; thus if E'l = secondary e.m.f, per circuit. El = aE'i = secondary e.m.f. per circuit reduced to primary system ; 210 ALTERNATING-CURRENT PHENOMENA if I' I = secondary current per circuit, Ii = -J- = secondary current per circuit reduced to primary system ; if r'l = secondary resistance per circuit, Vi = a-hr'i = secondary resistance per circuit reduced to pri- mary system; if x'l = secondary reactance per circuit, Xi = a^bx'i = secondary reactance per circuit reduced to pri- mary system; if z'l = secondary impedance per circuit, 2i = a^hz'i = secondary impedance per cir ...... cuit. El = aE'i = secondary e.m.f. per circuit reduced to primary system ; 210 ALTERNATING-CURRENT PHENOMENA if I' I = secondary current per circuit, Ii = -J- = secondary current per circuit reduced to primary system ; if r'l = secondary resistance per circuit, Vi = a-hr'i = secondary resistance per circuit reduced to pri- mary system; if x'l = secondary reactance per circuit, Xi = a^bx'i = secondary reactance per circuit reduced to pri- mary system; if z'l = secondary impedance per circuit, 2i = a^hz'i = secondary impedance per circuit reduced to pri- mary system; that is, the ...Chapter 14: The Alternating-Current Transformer - 81 hit(s)
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... sine wave, but is, at least in the closed magnetic circuit transformer, greatly distorted by hysteresis, though less so in the open magnetic circuit transformer. It can, however, be represented by an equiv- alent sine wave, f00, of equal intensity and equal power with the distorted wave, and a wattless higher harmonic, mainly of triple frequency. Since the higher harmonic is small compared with the 196 ALTERNATING-CURRENT PHENOMENA. total exciting current, and the exciting current is only a small part of the total primary current, the higher harmonic .can, for most practical cases, be n ...... most practical cases, be neglected, and the exciting current represented by the equivalent sine wave. This equivalent sine wave, 7^, leads the wave of mag- netism, 3>, by an angle, a, the angle of hysteretic advance of phase, and consists of two components, — the hysteretic energy current, in quadrature with the magnetic flux, and therefore in phase with the induced E.M.F. = I00 sin a; and the magnetizing current, in phase with the magnetic fluXj and therefore in quadrature with the induced E.M.F., and so wattless, = I00 cos a. The exciting current, 700, is determined from the shape and mag ...Chapter 1: Electric Conduction. Soled And Liquid - 80 hit(s)
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... ed by the cir- cuit constant inductance, L, and the electrostatic component, characterized by the electric circuit constant capacity, C. Inside of the conductor we find a conversion of energy into heat; that is, electric power is consumed in the conductor by what may be considered as a kind of resistance of the conductor to the flow of electric power, and so we speak of resistance of the conductor as an electric quantity, representing the power consumption in the conductor. Electric conductors have been classified and divided into dis- tinct groups. We must realize, however, that there are no ...... characterized by the electric circuit constant capacity, C. Inside of the conductor we find a conversion of energy into heat; that is, electric power is consumed in the conductor by what may be considered as a kind of resistance of the conductor to the flow of electric power, and so we speak of resistance of the conductor as an electric quantity, representing the power consumption in the conductor. Electric conductors have been classified and divided into dis- tinct groups. We must realize, however, that there are no dis- tinct classes in nature, but a gradual transition from type to type. M ...Chapter 15: Constant-Voltage Series Operation - 79 hit(s)
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... unting film cutout punctures and puts the second lamp in circuit. However, in general such arrange- ment is too complicated for use. As practically all such circuits would be alternating-current circuits, and thus alternating currents only need to be considered, the question arises, whether a reactance shunting each lamp would not give the desired effect. Suppose each lamp, of resist- ance, r, is shunted by a reactance, x, which is sufficiently large not to withdraw too much current from the lamp: assuming the cur- rent shunted by x is 20 per cent, of the current in the lamp, or x = 5 r. Wit ...... ated for use. As practically all such circuits would be alternating-current circuits, and thus alternating currents only need to be considered, the question arises, whether a reactance shunting each lamp would not give the desired effect. Suppose each lamp, of resist- ance, r, is shunted by a reactance, x, which is sufficiently large not to withdraw too much current from the lamp: assuming the cur- rent shunted by x is 20 per cent, of the current in the lamp, or x = 5 r. With 6.6 amp. in r, x thus would take 1.32 amp., and the total, or line current would be: i = V6.6^ + 1.322 = 6.73 amp., t ...