The conception of the field of force, or, as we should more correctly say, the field of energy, thus takes the place of the conception of action at a distance and of the ether. The beam of light and the electromagnetic wave (like that of the radio communication station or that surrounding a power transmission line) are therefore periodic alternations of the electromagnetic energy field in space, and the differ- ences are merely those due to the differences of frequency. Thus the electromagnetic field of the 60-cycle transmission line has a wave length of 3 X lO^V^O cm. = 5000 km. Its extent is limited to the space between the conductors and their immediate surroundings, being therefore extremely small compared with the wave length, and under these conditions the part of the electromagnetic energy which is radiated into space is extremely small. It is so small that it may be neglected and that it may be s…
Ether And Relativity Passage Atlas
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Why This Theme Matters
Section titled “Why This Theme Matters”This passage may clarify exactly how Steinmetz uses, revises, or abandons ether language in context.
Candidate Passages
Section titled “Candidate Passages”In consequence of the relative motion of the primary and secondary, the magnetic circuit of the induction motor must be arranged so that the secondary while revolving does not leave the magnetic field of force. That means, the magnetic field of force must be of constant intensity in all directions, or, in other words, the component of magnetic flux in any direction in space be of the same or approximately the same intensity but differing in phase. Such a magnetic field can either be considered as the superposition of two magnetic fields of equal intensity in quad- rature in time and space, or it can be represented theoretically by a revolving magnetic flux of constant intensity, or rotating
If light is a wave motion, there must be something to move, and this hypothetical carrier of the light wave has been called the ether. Here our troubles begin. The phenomenon of polarization shows that light is a transverse wave; that is, the ether atoms move at right angles to the light beam, and not in its direction as. is the case with sound waves. In such transverse motion a vibrating ether atom neither approaches nor recedes from the next ether atom, and the only way in which in the propagation of the light wave the vibratory motion of each ether atom can be transmitted to the next one is by forces acting between the ether atoms so as to hold them together in their relative positions. Bodies in which the atoms are held together in their relative positions are solid bodies. That is, trans- verse waves can exist only in solid bodies. As the velocity of light is extremely high, the forces between the e…
110. Artificial light is used for the purpose of seeing and distinguishing objects clearly and comfortably when the day- light fails. The problem of artificial lighting thus comprises con- sideration of the source of light or the illuminant; the flux of light issuing from it; the distribution of the light flux in space, that is, the light flux density in space and more particularly at the illuminated objects; the illumination, that is, the light flux density reflected from the illuminated objects, and the effect produced thereby on the human eye. In the latter, we have left the field of physics and entered the realm of physiology, which is not as amenable to exact experimental determination, and where our knowledge thus is far more limited than in physical science. This then constitutes one of the main difficulties of the art of illuminating engineering: that it embraces the field of two dif- ferent scie…
former, the high-tension switches are opened at the generator end of the transmission line. The energy stored magnetically and dielectrically in line and transformer then dissipates by a transient, as shown in the oscillogram Fig. 41. This gives the oscillation of a circuit consisting of 28 miles of line and 2500-kw. 100-kv. step-up and step-down transformers, and is produced by discon- necting this circuit by low-tension switches. In the transformer, the duration of the transient would be very great, possibly several seconds, as the stored magnetic energy (L) is very large, the dis- sipation of power (r and g) relatively small; in the line, the tran- sient is of fairly short duration, as r (and g) are considerable. Left to themselves, the line oscillations thus would die out much more rapidly, by the dissipation of their stored energy, than the transformer oscillations. Since line and transformer are co…
former, the high-tension switches are opened at the generator end of the transmission line. The energy stored magnetically and dielectrically in line and transformer then dissipates by a transient, as shown in the oscillogram Fig. 41. This gives the oscillation of a circuit consisting of 28 miles of line and 2500-kw. 100-kv. step-up and step-down transformers, and is produced by discon- necting this circuit by low-tension switches. In the transformer, the duration of the transient would be very great, possibly several seconds, as the stored magnetic energy (L) is very large, the dis- sipation of power (r and g) relatively small; in the line, the tran- sient is of fairly short duration, as r (and g) are considerable. Left to themselves, the line oscillations thus would die out much more rapidly, by the dissipation of their stored energy, than the transformer oscillations. Since line and transformer are co…
As the electromagnetic field represents energy storage in space, it cannot extend through space instantaneously, but must propagate through space at a finite velocity, the rate at which the power radiated by the source of the field can fill up the space with the field energy. The field energy is proportional to the energy radiation of the source of the field (transmission line, radio antenna, incandescent body) and to the electromagnetic constants of space (permeability, or specific inductance, and permittivity, or specific capac- ity), and the velocity of propagation of the electromagnetic field - that is, the velocity of light - ^thus is:
Hence the logical error which led to the ether theory is the assumption that a w^ave must necessarily be a wave motion. A wave may be a wave motion of matter, as the water wave and sound wave, or it may not be a wave motion. Electrical engineering has dealt with alternating- current and voltage waves, calculated their phenomena and applied them industrially, but has never considered that anything material moves in the alternating-current wave and has never felt the need of an ether as the hypothetical carrier of the electric wave. When Maxwell and Hertz proved the identity of the electromagnetic wave and the light wave, the natural conclusion was that light is an electromagnetic wave, that the ether was unnecessary also
Suppose we have a permanent bar magnet M (Fig. 2) and bring a piece of iron / near it. It is attracted, or moved; that is, a force is exerted on it. We bring a piece of copper near the magnet, and nothing happens. We say the space surrounding the magnet is a magnetic field. A field, or field of force, we define as “a condition in space exerting a force on a body susceptible to this field.” Thus, a piece of iron being magnetizable - that is, susceptible to a magnetic field^ - ^will be acted upon; a piece of copper, not being magnetizable, shows no action. A field is completely defined and characterized at any point by its intensity and its direction, and in Faraday’s pictorial representation of the field by the lines of force, the direction of the lines of force represents the direction of the field, and the density of the lines of force represents the intensity of the field. To produce a field of force r…
67. In the theoretical investigation of electric circuits the velocity of propagation of the electric field through space is usually not considered, but the electric field assumed as instan- taneous throughout space; that is, the electromagnetic com- ponent of the field is considered as in phase with the current, the electrostatic component as in phase with the voltage. In reality, however, the electric field starts at the conductor and propa- gates from there through space with a finite though very high velocity, the velocity of light; that is, at any point in space the electric field at any moment corresponds not to the condi- tion of the electric energy flow at that moment but to that at a moment earlier by the time of propagation from the conductor to the point under consideration, or, in other words, the electric field lags the more, the greater the distance from the conductor.
80. Alternating-current motors are usually single-phase, since the possibility of commutation control makes the single-phase easier than a polyphase design. In the single-phase motor, the magnetic field flux is constant in direction, and the direction in quadrature to the main field flux thus is available for pro- ducing a suitable commutating flux. In the polyphase motor, however, the magnetic flux rotates, assuming successively all directions, and thus no commutating flux can be used. For this reason, designs of polyphase commutator motors have been made in which the different (2 and 3) phases are kept separate, and spaces left between them for accommodating commutating fluxes.
134. The operation of the induction motor thus can also be considered as due to the action of a rotating magnetic field upon a system of short-circuited conductors. In the motor field or primary, usually the stator, by a system of polyphase impressed e.m.fs. or by the combination of a single-phase impressed e.m.f. and the reaction of the currents produced in the secondary, a rotating magnetic field is produced. This rotating field produces currents in the short-circuited armature or secondary winding, usually the rotor, and by its action on these currents drags along the secondary conductors, and thus speeds up the armature and tends to bring it up to synchronism, that is, to the same speed as the rotating field, at which speed the secondary currents would disappear by the armature conductors moving together with the rotating field, and thus cutting no lines of force. The secondary therefore slips in spe…
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 the field reverse simul- taneously with the armature. If the reversal of field magnetism should occur later than the reversal of armature current, during the time after the armature current has reversed, but before the field has reversed, the motor torque would be in opposite direc- tion and thus subtract; that is, the field magnetism of the alter- nating-curren…
103. In general, an alternating-current transformer conafete of a magnetic circuit, interlinked with two electric circuits or sets of electric circuits, the primary circuit, in which power, sup- plied by the impressed voltage, is consumed, and the secondary circuit, in which a corresponding amount of electric power is produced; or in other words, power is transferred through space, by magnetic energy, from primary to secondary circuit. This power finds its mechanical equivalent in a repulsive llirusi acting between primary and secondary conductors. Thus, if the secondary is not held rigidly, with regards to the primary, it will be repelled and move. This repulsion is used in the constant-current transformer for regulating the current for constancy independent of the load. In the induction motor, this mechanical force is made use of for doing the work: the induction motor represents an alternating-current…
44. Such circuits with distributed series capacity are of great interest in that it is probable that lightning flashes in the clouds are discharges in such circuits. From the distance traversed by lightning flashes in the clouds, their character, and the disruptive strength of air, it appears certain that no potential difference can exist in the clouds of such magnitude as to cause a disruptive discharge across a mile or more of space. It is probable that as the result of condensation of moisture, and the lack of uni- formity of such condensation, due to the gusty nature of air currents, a non-uniform distribution of potential is produced between the rain drops in the cloud; and when the potential gradient somewhere in space exceeds the disruptive value, an oscillatory discharge starts between the rain drops, and grad- ually, in a number of successive discharges, traverses the cloud and equalizes the pot…
istics of the illuminant, while flux density is a function of the space traversed by the light flux, but not of the source of light : with the same source of light, in the space from the surface of the illuminant to infinite distance, all light flux densities exist between the maximum at the surface of the illuminant (its brilliancy) and zero. Brilliancy thus is the maximum of the light-flux density. While intensity and brilliancy depend upon the shape of the illuminant, light flux is independent thereof. Illumination is a quantity which depends not only on the source of light, that is, light flux and flux density, but also on the illumi- nated objects and their nature, and thus is the light flux density as modified by the illuminated objects. Very commonly, how- ever, the term ” illumination ” is used to denote ” light flux density,” irrespective of the illuminated objects.
The unit of light intensity, or the candle power thus given, with a radiator of uniform light-flux distribution, 4 x lumens of light flux, and inversely, a radiator which gives 4 it lumens of light flux, gives an intensity of one candle, if the intensity is uniform in all directions, and, if the distribution of the intensity is not uniform, the average or mean spherical intensity of the radiator is one candle. Thus one mean spherical candle rep- resents 4 it lumens of light flux, and very frequently the mean spherical candle is used as representing the light flux: the light flux is 4 TT times the mean spherical intensity, and the mean spherical intensity is the total light flux divided by 4 it, regard- less whether the light flux is uniformly distributed or not.
The phenomenon of interference proves that light is a wave, a periodic phenomenon, just like an alternating current. Thus the wave theory of light and radiation stands today as unshaken as ever. However, when this theory was established, the only waves with which people were familiar were the waves in water and the sound waves, and both are wave motions. As the only known waves were wave motions, it was natural that the light wave also was considered as a wave motion. This led to the question of what moves in the light wave, and thus to the hypothesis of the ether, with all its contradictory and illogical attri- butes. But there is no more reason to assume the light wave to be a wave motion than there is to assume the alternating-current wave to be a motion of matter. We know that nothing material is moving in the alternating- current or voltage wave, and if the wave theory of light had been propounded a…
The magnetic field of any induction motor, whether supplied by polyphase, monocyclic, or single-phase e.m.f., is at normal condition of operation, that is, near synchronism, a polyphase field. Thus to a certain extent all induction motors can be called polyphase machines. When supplied with a polyphase system of e.m.fs. the internal reactions of the induction motor are simplest and only those of a transformer with moving second- ary, while in the single-phase induction motor at the same time a phase transformation occurs, the second or magnetizing phase being produced from the impressed phase of e.m.f. by the rota- tion of the motor, which carries the secondary currents into quadrature position with the primary current.
In an ununiform electric conductor, the relation of the voltage to the length of the conductor does not determine whether the conductor is safe or whether locally, due to small cross-section or high resistivity, unsafe current densities may cause destructive heating, but the adaptability of the conductor to the current carried by it must be considered throughout its entire length. So in the dielectric field, the thickness of the dielectric may be such that the voltage impressed upon it may give a very safe average voltage gradient or average dielectric flux density, and the dielectric nevertheless may break down, due to local concen- tration of the dielectric flux density in the insulating material. Thus, for instance, in the dielectric field between parallel con- ductors, at a voltage far below that which would jump from conductor to conductor, locally at the conductor surface the concentration of elect…
Maxwell then has deduced mathematically, and Hertz demonstrated experimentally, that the alternating electro- magnetic field - that is, the electromagnetic wave - has the same speed of propagation as the light wave, and has shown that the electromagnetic wave and the (polarized) light wave are identical in all their properties. Hence light is an electromagnetic wave - that is, an alternating electro- magnetic field of extremely high frequency.
Similar transient phenomena also occur in space, that is, with space, distance, length, etc., as independent variable. Such transient phenomena then connect the conditions of the electric quantities at one point in space with the electric quantities at another point in space, as, for instance, current and potential difference at the generator end of a transmission line with those at the receiving end of the line, or current density at the surface of a solid conductor carrying alternating current, as the rail return of a single-phase railway, with the current density at the center or in general inside of the conductor, or the distribution of alternating magnetism inside of a solid iron, as a lamina of an alternating-current transformer, etc. In such transient phenom- ena in space, the electric quantities, which appear as functions of space or distance, are not the instantaneous values, as in the preceding…
Magnetic and dielectric fields are usually combined, since where there is a current producing a magnetic field there is a voltage producing a dielectric field. Thus the space surrounding a conductor carrying an electric current is an electromagnetic field - that is, a combination of a magnetic field, concentric with the conductor, and a dielectric field, radial to the conductor.
There obviously is no more sense in thinking of the capacity current as current which charges the conductor with a quantity of electricity, than there is of speaking of the inductance voltage as charging the conductor with a quantity of magnetism. But while the latter conception, together with the notion of a quantity of magnetism, etc., has vanished since Faraday’s representation of the magnetic field by the lines of magnetic force, the termi- nology of electrostatics of many textbooks still speaks of electric charges on the conductor, and the energy stored by them, without considering that the dielectric energy is not on the surface of the conductor, but in the space outside of the conductor, just as the magnetic energy.
There obviously is no more sense in thinking of the capacity current as current which charges the conductor with a quantity of electricitj^, than there is of speaking of the inductance voltage as charging the conductor with a quantity of magnetism. But while the latter conception, together with the notion of a quantity of magnetism, etc., has vanished since Faraday’s representation of the magnetic field b}^ the lines of magnetic force, the termi- nology of electrostatics of many textbooks still speaks of electric charges on the conductor, and the energy stored by them, without considering that the dielectric energy is not on the surface of the conductor, but in the space outside of the conductor, just as the magnetic energy.
in generator, line, and load does not represent the entire phenome- non. While electric power flows over the line A , there is a magnetic field surrounding the line conductors, and an electrostatic field issuing from the line conductors. The magnetic field and the electrostatic or “dielectric ” field represent stored energy. Thus, during the permanent conditions of the flow of power through the circuit Fig. 3, there is electric energy stored in the space surround- ing the line conductors. There is energy stored also in the genera- tor and in the load ; for instance, the mechanical momentum of the revolving fan in Fig. 1, and the heat energy of the incandescent lamp filaments. The permanent condition of the circuit Fig. 3 thus represents not only flow of power, but also storage of energy. When the switch S is open, and no power flows, no energy is stored in the system. If we now close the switch, before t…
in generator, line, and load does not represent the entire phenome- non. While electric power flows over the line A, there is a magnetic field surrounding the line conductors, and an electrostatic field issuing from the line conductors. The magnetic field and the electrostatic or ” dielectric ” field represent stored energy. Thus, during the permanent conditions of the flow of power through the circuit Fig. 3, there is electric energy stored in the space surround- ing the line conductors. There is energy stored also in the genera- tor and in the load ; for instance, the mechanical momentum of the revolving fan in Fig. 1, and the heat energy of the incandescent lamp filaments. The permanent condition of the circuit Fig. 3 thus represents not only flow of power, but also storage of energy. When the switch S is open, and no power flows, no energy is stored in the sj^stem. If we now close the switch, before…
Suppose now, in Fig. 2, instead of a periuanent magnet M, we have a bundle of soft iron wires with a coil of insul- ated copper wire around it and send a constant direct cur- rent through the latter. We then have an electromagnet, and the space surrounding M is a magnetic field, character- ized at every point by an intensity and a direction. If now we increase the current, the magnetic field increases; if we decrease the current, the field decreases ; if we reverse the current, the field reverses; if we send an alternating current through the coil, the magnetic field alternates - that is, is a periodic phenomenon or a wave, an alternating magnetic field wave.
44. However, the formation of continuous oscillations, Figs. 61 to 65, from the recurrent oscillations. Figs. 59 and 60, is not a mere running together and overlapping of successive wave trains. In Fig. 59, the succeeding oscillation cannot start, until the pre- ceding oscillation has died out and a sufficient time elapsed, for the line to charge again to a voltage which is high enough to dis- charge to ground and so start the next oscillation, that is, to store the energy for the next oscillation. If then, with an overlap of successive oscillations, no dead 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 osci…
3. Regarding the nature of radiation, two theories have been proposed. Newton suggested that light rays consisted of extremely minute material particles thrown off by the light- giving bodies with enormous velocities, that is, a kind of bom- bardment. This theory has been revived in recent years to explain the radiations of radium, etc. Euler explained the light as a wave motion. Which of these explanations is correct can be experimentally decided in the following manner: Assum- ing light to be a bombardment of minute particles, if we com- bine two rays of light in the same path they must add to each other, that is, two equal beams of light together give a beam of twice the intensity. If, however, we assume light is a wave motion, then two equal beams of light add to one of twice the intensity only in case the waves are in phase, as Al and B^ in Fig. 3 add to Cr If, however, the two beams A2 and B2 are n…
The intensity of a light source is measured in candles. The unit of light intensity, or the candle, is a quantity not directly related to the absolute system of units, but reproduced from specifica- tions or by comparison with maintained standards, and for white light is probably between 0.04 and 0.02 watt. Intensity has a meaning only for a point source of light; that is, an illumi- nant in which the flux of light issues from a point or such a small area that, at the distance considered, it can be considered as a point. ” Intensity of light ” thus is a physical quantity of the same nature as ” intensity of magnet pole,” which latter also presupposes that the total magnetic flux issues from a point, and thus is applicable only when dealing with such distances from the source of the light flux or magnetic flux, that the flux can be assumed as issuing from a point. Frequently the inten- sity of a light sou…
The frequency of the secondary E.M.F. of the first motor, and thus the frequency impressed upon the second motor, is the frequency of slip below complete synchronism, s. The frequency of the secondary induced E.M.F. of the second motor is the difference between its impressed frequency, s, and its speed ; thus, if both motors are connected together mechanically to turn at the same speed, 1 - s, the secondary frequency of the second motor is 2^-1, hence equal to zero at s = .5. That is, the second motor reaches its syn- chronism at half speed. At this speed its torque becomes equal to zero, the energy current flowing into it, and conse- quently the energy component of the secondary current of the first “motor, and thus the torque of the first motor be- comes equal to zero also, when neglecting the hysteresis energy current of the second motor. That is, a system of concatenated motors with short-circuited s…
The theory of relativity of Einstein and his collaborators has profoundly revolutionized our conceptions of nature. Time and space have ceased to be entities and have become mere forms of conception. The length of a body and the time on it and the mass have ceased to be fixed properties and have become dependent on the conditions of obser- vation. The law of conservation of matter thus had to be abandoned and mass became a manifestation of energy. The law of gravitation has been recast, and the force of gravitation has become an effect of inertial motion, like centrifugal force. The ether has been abandoned, and the field of force of Faraday and Maxwell has become the fundamental conception of physics. The laws of mechanics ^ have been changed, and time and space have been bound’ together in the four-dimensional world space, the dimen- sions of which are neither space nor time, but a symmetrical combinat…
Thus with the distributed armature winding, which is now al- most exclusively used, the wave-shape distortion due to the non- sinusoidal distribution of the field flux is greatly reduced, that is, the higher harmonics in the voltage wave decreased, the more so, the higher their order, and very high harmonics, such as the seven- teenth, thirty-fifth, etc., therefore do not exist in such machines to any appreciable extent, except where produced by other causes. Such are a pulsation of the magnetic reluctance of the field due to the armature slots, or a pulsation of the armature reactance, as discussed in Chapter XXV of ** Theory and Calculation of Alter- nating-current Phenomena,” or a space resonance of the armature conductors with some of the harmonics. The latter may occur if the field flux distribution contains a harmonic of such order, that the voltages induced by it are in phase in the successive ar…
113. Thus far, the problem is one of physics, and the result, that is, the objective illumination, can be measured by photometer or luminometer, and thus checked. The duty of the illuminat- ing engineer, however, does not end here, but with the same objective illumination, that is, the same distribution of light flux throughout the entire illuminated area, as measured by photometer, the illumination may be very satisfactory, or it may be entirely unsatisfactory, depending on whether the physio- logical requirements are satisfied or are violated ; and very often we find illuminations which seem entirely unsatisfactory, tiring, or uncomfortable, but when judged by the density and the distribution of the light flux, should be satisfactory. Even numerous commercial illuminants, designed to give suitable distribution curves, fail to do justice to their light flux and its distribution, by violating fundamental…
163. The total flow of power of a balanced symmetrical poly- phase system is constant. That is, the sum of the instantaneous values of power of all the phases is constant throughout the cycle. In the single-phase system, however, or in a polyphase system with unbalanced load, that is, a system in which the different phases are unequally loaded, the total flow of power is pulsating, with double frequency. To balance an unbalanced polyphase system thus requires a storage of energy, hence can not be done by any method of connection or transformation. Thus mechanical momentum acts as energy-storing device in the use as phase bal- ancer, of the induction or the synchronous machine. Electrically, energy is stored by inductance and by capacity. The question then arises, whether by the use of a reactor, or a condenser, con- nected to a suitable phase of the system, an unequally loaded polyphase system can be bal…