CHAPTER IX. INDUCTIVE DISCHARGES. 64. The discharge of an inductance into a transmission line may be considered as an illustration of the phenomena in a complex circuit comprising sections of very different constants; that is, a combination of a circuit section of high inductance and small resistance and negligible capacity and conductance, as a generating station, with a circuit of distributed capacity and inductance, as a transmission line. The extreme case of such a discharge would occur if a short circuit at the busbars of a gen- erating station opens while the transmission line is connected to the generating station. Let r = the total resistance and L = the total inductance of the inductive section of the circuit; also let g = 0, C= 0, and L0 = inductance, <70 = capacity, r0 = resistance, g0 = conduc- tance of the total transmission line connected to the inductive circuit. In either of the two circuit sections the total length of the section is chosen as unit distance, and, translated to the velocity measure, the length of the transmission line is and the length of the inductive circuit is ~T = 0; (374) that is, the inductive section of zero capacity has zero length when denoted by the velocity measure X, or is a "massed induc- tance." It follows herefrom that throughout the entire inductive section X = 0, and current i1 therefore is constant throughout this section. Choosing now the transition point between the inductance and the transmission line as zero of distance, A = 0, the inductance 635 536 TRANSIENT PHENOMENA is massed at point ^ = 0, and the transmission line extends from X = 0 to X = V Denoting the constants of the inductive section by index 1, those of the transmission line by index 2, the equations of the two circuit sections, from (290), are Cj) cos qt — -(51 + 7)1)sin^},l - A-DJsing*}; j (376) i2 = £-Uot{s +sA [A2 cos q (X - t) + B2 sin g (^ - t)] — s~s* [C9 cos q (A + t) + Z), sin 0 (^ + £)"]}. L / Z\ / ^ 1\ x-!)^ e2 = ca e-rt {[£+^ [A2 cos g (^ - 0 + J52 sin q (I - t)] + £~sA [Ca cos g (^ + 0 + D2 sin q (Jl + 0]}, and the constants of the second section are related on those of the first section by the equations (285) : A - n A 4- 7) n C1 Aj - «!/!.! "I' Oil/ti ^2 D „ D ^\ T\ T\ •D n == U/fJJ-i t/1iyi. -^'•5 where «,=VC-' (286) + (349) and (287) 65. In the inductive section having the constants L and r, that is, at the point A = 0 of the circuit, current il and voltage et must be related by the equation of inductance, (377) Substituting (375) in (377), and expanding, gives ci { (Ai + CJ cos qt - (B^ - DJ sin qt] = (r + w0L) { (At - C,) cos qt - (B^ + D,) sin qt} + ^L { (Al - CJ sin ^ + (B1 + DJ cos qt}, INDUCTIVE DISCHARGES and herefrom the identities Cl (A, + C,) = (r + ^) (^i ~ Ci) + ^ (*i + *>i), Cl (B,-D,) = (r + u0L) (5, + ig - gL (Ax- CJ. Writing and gives cx (AA + CJ = (r + w0^) M + 3LN ] and | c, (5, - Dx) = (r + w0L) A^ - gLM, J which substituted in (349) gives A2 = — { (c + r + w0£) ^ + ^^ } ^ - (M + p^V), J52 = 1 { (c + r + u0L) N - qLM} ~*:(N - pM), z c £ 537 (378) (379) (380) - Z C - (c - r - -f (c - r- m0L) - M), JV), (381) where in the second expression terms of secondary order have been dropped. P qL Then substituting in (375) gives the equations of massed inductance : it = e ~M { M cos qt - N sin qt } (382) If at t = 0, £j = 0, that is, if at the beginning of the transient discharge the voltage at the inductance is zero, as for instance the inductance had been short-circuited, then, substituting in 538 TRANSIENT PHENOMENA (382), and denoting by i0 the current at the moment t = 0, or at the moment of start, we have t = 0, i\= %,«! = 0; hence, M = i (383) and r T -}- u Li h = V~"u* 1 cos <# + -r2" sm ^ gL + (r + V')2 , (384) In this case i A*=2' 2 + (r + uQL)2 + c (r \ - \J s f / (385) + (r + ^0L)2 - c (r + 66. In the case that the transmission line is open at its end, at point A = ^0, >l = 1 ?•-*-?' i. hence, this substituted in (376), expanded and rearranged as function of cos qt and sin qt, gives the two identities £+sA° (A, cos g;o+ B2 sin gao) « fi-^ (C2 cos q*0 + D2 sin ^, and c+«fc// (386) Squared and added these two equations (386) give (A? + £2) . ,-2^o C2 + D 2> (387) INDUCTIVE DISCHARGES 539 Divided by each other and expanded equations (386) give (Af, - B2DJ sin 2 gA0 - (A2D2 + B2C2) cos 2 qXQ. (388) Substituting (381) into equations (387) and (388) gives 2^{(qL)2 + (c + r + u0L)2}=e-*s**{(qL)2+(c-r-uQL)2} (389) { (qL)2 + (r + u,L)2 - c2 \ sin 2 qXQ = 2 cgL cos 2 ^0. (390) Since 2 s^0 is a small quantity, in equation (389) we can sub- stitute hence, rearranging (389) and substituting s = u0 — u gives c (r + u0L) - (u - u0) ;0 { (qL)2+(r + u0L)2 + c2 } = 0. (391) Since (r + u0L) is a small quantity compared with c2 (qL)2, it can be neglected, and equations (390) and (391) assume the form { (qL)2 - c2 } sin 2 gA0 = 2 cqL cos 2 q*Q (392) c (r + u,L) - (u - UQ) *0 { (qL)2 + c2} = 0, (393) and, transformed, equation (392) assumes the form 2cqL tan 2 or or (qL)2 - c2 ' q = - - tan ql0, (394) q = + -f cot g^0, L hence tan 2 q^ is positive if #L > c, as is usually the case. Expanded for u0, equation (393) assumes the form +cL or (L+r-) V wl u cL + ^0 { (qL)2 + c2 } s = - (u - u0). (395) 540 TRANSIENT PHENOMENA From equations (394) q is calculated by approximation, and then from (395) u0 and s. As seen, in all these expressions of q, uw s, etc., the integration constants M and N eliminate; that is, the frequency, time atten- uation constant, power transfer, etc., depend on the circuit con- stants only, but not on the distribution of current and voltage in the circuit. 67. At any point X of the circuit, the voltage is given by equa- tion (376), which, transposed, gives e = c£-wo<{£+^ [(42 cos q% + %2 sin qX) cos qt + (A2 sin qX — B2 cos qX) sin qt] + e~sA [(C2 cos qX + D2 sin qX) cos qt — (C2 sin qX — D2 cos qX) sin qt] } , or approximately, e = cs~u<* {[(A2 + C2) cos qX + (B2 + D2) sin qX] cos qt + [(A2 - C2) sin g^ - (B2 - D2) cos ^] sin qt}. Similarly to equation (381), A2 + C2 = pN', A2-C2 = M; B* + D2 = N; (396) where then T) — • cos ^A+c sin gd) (JV cos ^ + M sin ^), (cos ^ _ sin cos g« - N sin $); ^1 (N cos qt + M sin $), (M cos qt-N sin g«). (397) (398) INDUCTIVE DISCHARGES 541 If hence, e, = 0 for t = 0, N = 0; h = V ~^ cos $> '2 " 0 , <1L • n (cos qX - - sin g/) cos c c sn Writing (M2 the effective values of the quantities are I2 = E2 = I0e~u<* (qL cos q\ + c sin gA). . Herefrom it follows that /2 = 0 for A = ^0 by the equation cos aAn - q- sin gA0 = 0, or while gives that is, q - zco «- - ^L cos ql0 + c sin gA0 = 0; (399) (400) (401) (402) (403) 0 at 542 TRANSIENT PHENOMENA At the open end of the line ^ = tuting (402) into (401) is the voltage E2 by substi- cos If + At the grounded end of the line X = stituting (403) into (401), is 7 ~ — U(jt, V (404) the current 72, by sub- (405) An inductance discharging into the transmission line thus gives an oscillatory distribution of voltage and current along the line. 68. As example may be considered the three-phase high- potential circuit, comprising a generating system of r = 2 ohms and L = 0.5 henry per phase and connected to a long-distance transmission line of r0= 0.4 ohm, L0 = 0.002 henry, gQ= 0.2 X 10~6 mho, (70= 0.016 X 10~6 farad per mile of conductor or phase, and of 1Q = 80 miles length. c =\/- = c2 = 125,300; i + 0.067 sin qX). (4) Full wave: 362.89°. ?4 •• 14,010; w0 = 105.1; 7 = v~^ (cos qX - 19.8 sin qX); E = 7005 v~^ (cos qX + 0.050 sin qX). (5) Five-quarter wave: 452.32°. -^ (cos qX + 0.040 sin gj). 544 TRANSIENT PHENOMENA (6) Three-half wave: 541.94°. & = 20,920; UQ = 105.6; 7 = if-** (cos qX- 29.6 sin gd); jE/ = 10,460 v~Wo< (cos g>l + 0.033 sin qX). APPENDIX VELOCITY FUNCTIONS OF THE ELECTRIC FIELD IN the study of the propagation of the electric field through space (wireless telegraphy and telephony), a number of new functions appear (Section III, Chapter VIII). . By the following equations these functions are defined, and related to the " Sine-Integral" Si x, the " Cosine-Integral" Ci x, and the " Exponential Integral," Ei x, of which tables were calculated by J. W. L. Glaisher (Philosophical Transactions of the Royal Society of London, 1870, Vol. 160) : col x = — du u* u5 u7 du l_v? }_u? l 3\3+55~7 |2 [4 |6 = cosxj--^+p-p+-...j fl |3 |S |7 H-sinz -§-^ + ^-^5 I 71 /^ sin u 2"Jo « du. 545 546 sil x= I du APPENDIX rx cos u ll x= ~>1~( Jx C*\i-- --- 1-^ 1 u2 1 u* 1 IX4 l |3 |5 |7 — -^+i=-^ a;2 a^ x6 x8 l 2 |4 |5 --%4^-ty X X3 X5 X7 fx ^du; where r= 0.5772156 . . . /•40, the approximation is correct to the 6th decimal. For small values of x, the approximations hold : si\x = log- -0.5772156, For large values of x, it is : 2 sin x 2 sin x 2 cos x 2 cos - < col x < — where n\ and n2 are the two successive quadrants, between which x lies. For instance : sin x = sin 1.5^"= 0.707, cos x = cos 1.5^-= —0.707, 550 APPENDIX and 0.01 725 80 j»fe 79 X sil|s=(-l) + 1 2~2 INDEX PAGE Acceleration constant of traveling wave 466 Air blast, action in oscillating-current generator 75 pressure required in oscillating-current generator 75 Alternating-current circuit and transient term of fundamental frequency 473 distribution in conductor 369 transformer operating oscillating-current generator 87 transmission, equations of traveling wave 477 wave as traveling wave without attenuation 472 Alternator control by periodic transient term of field excitation 223 Aluminum cell rectifier 222 effective penetration of alternating current 378 Amplitude of traveling wave 465 of wave 438 Arc, and spark 249 continuity at cathode 249 lamp, control by inductive shunt to operating mechanism 131 machine 230 as rectifier 221 current control 220 properties 249 rectification 249 rectifiers 222 resistivities 9 starting 249 Arcing ground on lines and cables, as periodic transient phenomenon . . 23 Armature reactance, reaction and short-circuit current of alternator 199 Attenuation of alternating magnetic flux in iron 361 constants 434 of traveling wave, and loading 462 Booster, response to change of load 158 Brush arc machine 221, 230, 242, 248 Building up of direct-current generator 32 of overcompounded direct-current machine 49 Cable, high-potential underground, standing waves 452 opening under load 112, 118 short-circuit oscillation 113, 118 starting 111,117 transient terms and oscillations 98, 102 561 562 INDEX PAGE Capacity, also see Condenser. and inductance, equations 48 and velocity of propagation 400, 401 distributed series 348 energy of complex circuit 517 in mutual inductive circuit 161 of electric circuit 112 range in electric circuit 13 representing electrostatic component of electric field 5 shunting direct-current circuit 133 specific, numerical values 11 suppressing pulsations in direct-current circuit 134 Cast iron, effective penetration of alternating current 378 Cathode of arcs 249 Charge of condenser 51 of magnetic field 27 Circuit, complex, see Complex circuit. control by periodic transient phenomena 220, 223 electric, speed of propagation in 422 Closed circuit transmission line 306 Col al 392, 394 Commutation and rectification 222 as transient phenomenon 40 Commutator, rectifying 229 Complex circuit, of waves 498 power and energy 513 resultant time decrement 504 traveling wave 468 Compound wave at transition point 532 Condenser, also see Capacity. charge, inductive 18 noninductive 18 circuit of negligible inductance 55 equations 48 oscillation, effective value of voltage, current and power. ... 70 efficiency, decrement and output 72 frequency 62 general equations 60 size and rating 69 starting on alternating voltage 94 voltage in inductive circuit 49 Conductance, shunted, effective 12 Conductors at high frequency 403 Constant-current mercury arc rectifier 250 rectification 221, 230 potential-constant-current transformation by quarter-wave line 308 mercury arc rectifier 251 rectification 221, 230 INDEX 563 PAGE Control of circuits by periodic transient phenomena 220 Conversion by quarter-wave circuits 313 Copper, effective penetration of alternating currents 378 ribbon, effective high frequency impedance 408 wire, effective high frequency impedance 408 Cosine wave, traveling 434 Critical case of condenser charge and discharge 53 resistance of condenser oscillation 66 start of condenser on alternating voltage 95 Current density, in alternating-current conductor 372 effective, of oscillating-current generator 81 transformation at transition point of wave 529 Damping of condenser oscillation 66, 72 Decay of continuous current in inductive circuit 17 of wave of condenser oscillation 72 Decrement of condenser oscillation 65, 72 resultant time, of complex circuit 504 Destructive voltages in cables and transmission lines 120 Dielectric constant, numerical values 11 strength, numerical values 11 Dielectric also see Electrostatic. Direct-current generator, self-excitation 32 railway, transient effective resistance 379 Disappearance of transient term in alternating-current circuit 43 Discharge of condenser , . 51 Geissler tube 9 inductive, as wave 535 into transmission line '. 542 of motor field 29 Disruptive strength, numerical values 11 voltage in opening direct-current circuit 26 Distance attenuation constant 434 in velocity measure . 435 Distortionless circuit 441, 447 Distributed series capacity 348 Distribution of alternating-current density in conductor 369 of alternating magnetic flux in iron 355 Divided circuit, general equations 122 continuous-current circuit without capacity 126 Dynamostatic machine 220 Effective current of condenser discharge 70 voltage and power of oscillating-current generator. . . 81 layer of alternating-current conductor 377 penetration of alternating current in conductor 376, 378 power of complex circuit 514 of cpndenser oscillation '70 reactance of armature reaction 200 561 INDEX PAGE Effective resistance of alternating-current distribution in conductor, 370, 376 voltage of condenser oscillation 70 Efficiency of condenser oscillation 72 Electric circuit, general equations 428 field, velocity of propagation 387 Electrolytes, resistivities 8 Electrolytic rectifiers 222 Electromagnetic, also see Magnetic. axis of electric field 4 Electrostatic, also see Dielectric. axis of electric field 4 energy of complex circuit 517 field, energy of 7 Elimination of pulsations in direct-current circuit by capacity 134 Energy of complex circuit 513 condenser discharge 70 electric field 4, 7 transfer in complex circuit 507, 521 constant of complex circuit 507 Equations, general, of electric circuit 428 Even harmonics of half-wave oscillations 483 Excitation of motor field 27 Exponential curve of starting current 45 Field current at armature short-circuit . t 202 electric, of conductor 3 energy of 4 velocity of propagation 387 excitation, transient term 27 exciting current, rise and decay 17 regulation of generator by periodic transient terms 223 resultant polyphase , 192 Flat conductor, unequal current distribution 371 Floating system of control 220 Fluctuations of current in divided circuit 129 voltage of direct-current generator with load 149 Free oscillations 432, 478 and standing waves 482 Frequency, absence of effect on circuit oscillation 10 and starting current of transformer 182 constant of wave 433 limit of condenser oscillation 73 of condenser oscillation 62, 68 field current at armature short-circuit 203 oscillation of condenser, transmission line, cable. ... 99, 338 recurrence of discharge in oscillating-current generator. . 81 wave 433 range of condenser oscillation 71 electromagnetic induction 67 INDEX 565 PAGE Full-wave oscillation of complex circuit 508 transmission line 330 Fundamental frequency of oscillation, cables and transmission lines 103, 105 Gas pipe, effective high frequency impedance 408 General circuits with inductance and capacity 174 without capacity 168 equations of electric circuit 428 Generator, direct-current over-compounded, building up 149 self-excitation 32 oscillating current 74 German silver, effective penetration of alternating current 378 Gradual approach to permanent value 21 or logarithmic condenser charge and discharge 53 term, also see Logarithmic. Graphite, effective penetration of alternating current 378 Grounded transmission line 303 Half-wave oscillation 483, 490 of complex circuit 509 transmission line 333 rectification 221 Harmonics, even, of half-wave oscillation 483 Hertzian oscillators 388 High frequency alternators, momentary short-circuit current 201 conductor 370, 403 discharge 388 oscillating currents by periodic transient terms 220 oscillations of cables and transmission lines 103, 105 power surge of low-frequency 105 stray field and starting current of transformer 189 Impact angle at transition point of wave 527 Impedance of conductor at high frequency 407 effective high frequency 408, 413 of radiation 396 traveling wave 460 Inductance and shunted capacity suppressing pulsations in direct-cur- rent circuit 134 effective, of radiation 394 energy of complex circuit 515 in telephone lines 455, 462 massed, in circuit 537 of conductor without return 390 electric circuit 12 range in electric circuit 13 representing magnetic component of electric field 5 566 INDEX PAGE Induction, magnetic, and starting current of transformer 180 motor circuit, starting 44 Inductive discharges into transmission line 542 shunt to non-inductive circuit 129 Inductorium, equations 164 Infinitely long conductor 305 Input, see Power. Instantaneous power in complex circuit 514 Insulators, resistivities 9 Iron arc operated by oscillating-current generator 82 effective penetration of alternating current 348 wire, current distribution 370 and pipe, effective high frequency impedance 408 Laminated iron, alternating magnetic flux 355 pole series booster, response to voltage change 158 Layer, effective, of alternating-current conductor 377 Leakage in telephone lines 455, 463 Length of wave 433 Lighting circuit, starting 27, 44 Lightning arrester, multigap 348 conductors 370 discharges 388 in thunder cloud 350 Limit condition of condenser equations 50 of frequency of condenser oscillations 73 Loading of telephone lines 455, 462 Local oscillations of cables and lines 103, 105 Logarithmic decrement of con^jnser oscillation 65 or gradual condenser charge and discharge 53 start of condenser on alternating voltage 95 Low frequency surge in cables and lines 103, 105 stray field and starting current of transformer 189 Loxodromic spiral of starting current 46 Magnetic, also see Electromagnetic. density and starting current of transformer 180 energy of complex circuit 515 field, energy of 6 flux, alternating, in iron 355, 361, 363, 365, 366, 367 materials 10 saturation, numerical values 10 Magnet poles, solid, as mutual inductive circuit 155 Main axes of electric field 46 wave at transition point 531 Massed inductance and electric wave 537 Mechanical rectification 221, 229 Mercury arc rectifier 250 INDEX 567 PAGE Metallic conductors, resistivities 8 magnetic induction 10 Minimum wave length of oscillating currents 74 Motor circuit, alternating, starting 44 field, excitation 27 Multigap lightning arrester '. 348 Mutual impedance and velocity of propagation 399 inductance, equations 143 and velocity of propagation 397 inductive circuit with capacity 161 without capacity 144 of solid magnet poles 155 reactance : 143 Nominal generated e.m.f. and short-circuit current 200 Noninductive condenser circuit 54 shunt to inductive circuit 129 Nonoscillatory, see Gradual or Logarithmic. Open-circuit rectification 230 Opening of cable or transmission line under load 112, 118 of continuous-current circuit 26 Open transmission line 299 Oscillating-current generator 69, 74 and charging current 85 high-frequency currents by periodic transient terms 220 Oscillation, also see Condenser discharge. free, of circuit 432, 478 of rotating field in starting 197 transmission line 322, 333, 336, 338 Oscillatory approach to permanent value 21 case of alternating circuit 93 or trigonometric condenser charge and discharge 53 start of condenser on alternating voltage 95 Oscillograms of mercury arc rectifier 264 of transformer starting current 190 Output, also see Power. effective, of oscillating-current generator 81 Overcompounded direct-current generator, building up 149 Overlap of rectifying arcs 251 Overreaching of condenser charge 19 in noninductive branch of inductive circuit 131 Oversaturated transformer flux of starting current 181 Penetration, effective depth of, 405 of alternating current in conductor 376, 378 magnetic flux in iron 361, 363, 365 Period of recurrence 218 wave . . 433 568 INDEX PAGE Periodic transient terms 22, 218 Permanent term of alternating-current circuit 91 values of electric quantities 16 Permeability 9 apparent,, of iron for alternating currents 355, 367 Phase difference in transmission line 296 of wave and transient term 45, 91 Physical meaning of transient term 103 Polyphase alternator short circuit 202, 204 m.m.f ., resultant 192 rectification 230 Potential regulation by periodic transient terms 223 Power of complex circuit 513 component of high frequency impedance 412 gradient of electric circuit 3 electric field 48 output, effective, of oscillating-current generator 81 radiated by conductor 394, 397 transfer in complex circuit 521 constant of complex circuit 507 Propagation constant of wave 441 speed of, of wave 422 field 387 Pulsation of rotating field in starting 197 Pyroelectrolytes, resistivities 9 Quarter-phase rectification 230 Quarter-wave circuit 313 oscillation 483, 489 of complex circuit 509 transmission line 322 transformer 312 transmission line 306, 315 Quartic equation of divided circuit 126 Radiation, effective resistance 393 power of conductor 393, 397 resistance of conductor 403 Rail, effective penetration of alternating current 378 return of single-phase system 370 transient effective resistance 379 Railway, direct-current, transient rail resistance 379 motor, self-excitation as generator 38 single-phase, rail return 370 Rating of capacity and inductance 122 resistors, reactors, condensers 69 Ratio of currents,1 oscillating-current generator 82 Reactance, effective, of external field . . 406 INDEX 569 PAGE Reactance, effective (continued), of internal field 406 of armature reaction 200 mutual inductive 143 Reaction, armature, and short-circuit current 199 Reactor, size and rating 69 Rectification, and commutation 222 arc 249 by periodic transient terms 22, 221 constant-current 230, 242 potential 230, 236 mechanical 229 open-circuit 230 polyphase 230 quarter-phase 230, 242 reversal or change of circuit connections 221 short-circuit 230 single-phase 229, 231, 236 Rectifier, mercury arc 250 oscillograms 264 Rectifying commutator 222, 229 Recurrent transient terms 218 Reflected waves 431 at transition point 527, 531 Reflection angle at transition point 527 of wave 525 Refraction law of wave 534 of wave 525 ratio at transition point 534 Regulation of potential by periodic transient terms . 223 Remanent magnetism in starting transformer 181 Resistance, and starting current of transformer 185 effective, of alternating-current conductor 370, 376 of electric circuit 12 radiation, of conductor 393, 403 range in electric circuits 13 representing power gradient of electric field 6 specific, see Resistivity. thermal, of conductor 403 Resistivity, numerical values 8 Resistor, size and rating 69 Resonators, Hertzian 388 Resultant polyphase m.m.f 192 time decrement of complex circuit 504 Rise of continuous current in inductive circuit 17 voltage by transformation at transition point 529 Rotating field, polyphase 192 Ruhmkorff coil, equations 164 570 INDEX PAGE Salt solution, effective penetration of alternating current 378 Saturation, magnetic, numerical values 10 and transformer starting current 180 Screening effect of alternating currents 378 Self-excitation of direct-current generator 32 railway motor as generator 38 series generator 38 shunt generator 37 Self-inductance in direct-current circuits 26 and short-circuit current of alternator 199 Series capacity, distributed 348 generator, self-excitation 38 motor, self-excitation as generator 38 Short-circuit current of alternator 199, 201 oscillation of cables and lines 113, 118 rectification 229 Shunt generator, self-excitation 32 motor field excitation, change 27 Sil al 392, 394 Silicon, effective penetration of alternating current 378 Sine wave traveling 434 Single-phase alternator short-circuit 202 railway rail return 370 rectification 229 Solid magnet poles as mutual inductive circuit 155, 158 Space induction, magnetic 10 Spark discharge in cables and lines as periodic transient phenomenon. . 23 of condenser as periodic transient phenomenon 22 Speed, effect on discharge of motor field 29 propagation in electric circuit 422 of alternating magnetic flux in iron 366 Standing waves 439, 442 and free oscillations 482 Starting current of transformer, calculation 188 and frequency 182 magnetic saturation 180 remanent magnetism 181 resistance 185 stray field 184 oscillograms 190 of alternating current 43 continuous current 27 polyphase or rotating field 192, 197 oscillation of cables and lines Ill, 117 Static, see Electrostatic. phenomena 13, 105 Stationary waves 439, 442 Steel, effective penetration of alternating current 378 INDEX 571 PAGE Stored energy of complex circuit 515 Stranded conductor, effective resistance of current distribution 370 Stray field and starting current of transformer 184 Suppression of pulsations of direct current by capacity and inductance. 134 Synchronous reactance and short-circuit current 200 rectifier 221 Telegraph, wireless 388 cable, submarine, standing waves 454 Telephone 281 circuit, long distance, standing waves 454 Terminal conditions of condenser equations 50 Tesla transformer and oscillating-current generator 82 Thermal resistance of conductor 403 Third harmonic of short-circuit current 213 Thomson arc machine 221, 230 Thunder cloud, lightning discharge in 350 Time attenuation constant 434 constant, resultant, of complex circuit 504 decrement, resultant, of complex circuit 504 local, of traveling wave 460 Tirrill regulator 223 Transfer constant of energy, of complex circuit 507 of energy in oscillation of complex circuit 507, 521 Transformation ratio at transition point of wave 529 of voltage and current at transition point 529 Transformer, alternating, operating oscillating-current generator 87 distributed capacity 342 quarter-wave oscillation 312 starting 44 and magnetic saturation 180 Transient rail resistance with direct current 386 terms, conditions of their appearance 21, 23 of alternating-current circuit 91 capacity and inductance, physical meaning 103 fundamental frequency in alternating-current circuit 473 periodic 22 unequal current distribution 379 Transition period at change of circuit condition 16 points of wave 498 Transmission angle at transition point 527 line, characteristic curves 297 closed 306 constants 282 conversion by 308, 313 equations 284, 287 approximate 294 free oscillation . . 322 572 INDEX PAGE Transmission line (continued), frequency 100, 280, 320, 338 full-wave oscillation 336 general equations of standing waves 449, 452 grounded 303 half-wave oscillation 333 inductive discharges 542 infinitely long 305 natural period 280, 320 open 299 opening under load 112, 118 phase difference 296 quarter-wave 306, 313, 315 oscillation 322 radiation 283 resonance frequency 279 with higher harmonics 280 short-circuit oscillation 113, 118 starting 111,117 transient terms and oscillations 98, 102 Transmitted wave at transition point 527, 531 Traveling sine and cosine waves 434 waves, general equations 458 without attenuation, as alternating waves 472 Trigonometric or oscillatory condenser charge and discharge 53 term, see Oscillatory. Turbo alternators, short-circuit current 201 Unequal alternating-current distribution in conductor 370 transient-current distribution in conductor , 379 Velocity, also see Speed. measure o.f distance 435 of propagation of electric field 387 Voltage control by transient terms 223 drop, high frequency conductor 413 transformation at transition point of wave 529 variation of direct-current generator, with load 149 Voltmeter across inductive circuit, pulsation 132 Water, effective penetration of alternating current 378 Wave of alternating magnetism in iron 359 direct or main, and reflected 431 length of alternating magnetic flux in iron 361, 365 constant 434 minimum, of oscillating current 74 transmission 281 Wireless telegraphy 388 X-ray apparatus, equations 82 '1 883 6 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW BOOKS REQUESTED BY ANOTHER BORROWER ARE SUBJECT TO IMMEDIATE RECALL LIBRARY, UNIVERSITY OF CALIFORNIA, DAVIS D4613(7/92)M UCD LIBRARY 31175021293744