WEST, JULIUS HENRIK Electrical Engineer, 3743 Locust St., WHITTEMORE, CHARLES F. Secretary and General Supt. Davis Electrical Engineer, WORSWICK, A. E. Mutual Light and Power Co., R. W. Pope. Montgomery, Ala. N. S. Keith. WRAY, J. GLEN Cable Tester, Chicago Telephone Co, A. V. Abbott. D. C. Jackson. John E. Davies. Total, 48. 66 THE PRESIDENT:-I take great pleasure in introducing to you Mr. D. McFarlan Moore, who will read a paper entitled "A New Method for the Control of Electric Energy." American Institute of Electrical Engineers, New York, September 20, 1893, President Houston in the Chair. A NEW METHOD FOR THE CONTROL OF BY D. Mc FARLAN MOORE. The rapid growth of electrical science, and the almost daily unprecedented addition to it of new inventions, have caused those well versed in the present state of the art to greet new theories with a certain amount of doubt, owing to the large number of false alarms that have been sounded to tell the world that all present theories and methods will, in the future, be history; and that a new and revolutionizing principle has been discovered. Be that as it may, there is reason to believe that this paper treats largely of an heretofore uninvestigated branch of electrical science and phenomena which may be of great value to the commercial world, and of even greater interest to the scientific world. The key to this branch of science may be expressed in a few words, viz:-A varying-in-pressure contact in a vacuum, produced by a variable magnetic field. The present means for the control of electric currents-ohmic resistance is crude at its best, as in any form it is an uneconomical device. All existing forms of rheostats, regulators, resistance boxes, controllers, etc., are bulky, clumsy means for accomplishing a desired object. This is conspicuously illustrated in the case of stage regulators, which often occupy valuable floor space and consist of a tremendous weight and length of wire. That the design of apparatus for controlling current is a matter of great importance and is essential to all electrical installations, is exhibited in the fact that over half of the catalogues issued by electric manufacturing companies are given up to this class of electrical goods. Many problems in electrical engineering are considered impracticable, simply because of the weight and space required for resistance to enable the control of the current as desired. When one takes into consideration the multitude of switches of every conceivable shape, construction and design, but all having one aim in view-which none perfectly accomplishviz:—to break a current without deleterious sparking, it seems that, as all are designed on the same principle, a new principle should be employed which would perfectly accomplish the object desired, that is; break the current with practically no sparking. It would also be a very convenient feature if each switch would control the brilliancy of all lights on the circuit which it controls. The regulation of intensity of the incandescence of an electric filament has been a problem, the solution of which has been sought after by electricians in general the world over, and partial success has been attained by the use of the only known means, "dead resistance;" but this method can never be commercially successful, on account of very objectionable bulk, weight and heating of the resistance. The public in general demands the control of electric lamps. and the great convenience gained thereby. The massive regulators of dynamos, and starting boxes of motors should be supplanted by devices occupying but a few cubic inches of space. This is especially the case where the motor is not stationary, as in electric railway work. There is room for a cheap ampere meter, and still more room for a cheap mechanism to be used as an electric gauge; that is, an instrument which can be adjusted or set so that a current that has passed through it will have any desired quantity or quality. This device could be substituted in place of fusible cutouts and the multitude of appliances of a similar nature. It would be of great value in telegraphy. The application of electricity in medicine should also be improved. Lastly, the reducing of phosphorescent lighting to a commercial basis is desirable. It is hoped a solution of these and many other problems lies in the principle stated at the beginning of this paper, i.e., a varyingin-pressure contact in a vacuum produced by a variable magnetic field, and it is doubly valuable in that it can be applied F both to the alternating and the direct current. One of the simplest forms of apparatus designed for meeting these conditions is shown in Fig. 1. The varying-in-pressure contact is shown at A, caused by the variable magnetic field due to the movement of the magnet в by thumb screw c. The evacuated bulb r contains the armature D, supported by spring E, permitting it to vibrate rapidly, producing pulsations or interruptions of the current. The rate or degree of these interruptions depends on the strength of the magnetic field surrounding the armature (in this case acting through the glass), which in turn depends on the distance of the magnet from it, varying inversely as the square of the distance. Varying the magnetic field, and therefore the pressure on the contacts, changes the amperes and volts of the current passing through the device. With properly de signed apparatus the movement of the armature is so slight that to all appearances one would think it at rest. In the discussion of this method of current control, let us select that form of translating device known as the incandescent electric lamp. Fig. 2 is a diagram showing the action of a vibrator in series with a lamp, without the contacts in a vacuum. Its action is as follows:-Contact made at A; current flows through magnet and armature is attracted, breaking the circuit; magnet loses its power and spring s again closes the circuit. Fig. 3 shows the device as applied to each individual lamp, and it will be noted that in this case the vacuum of the lamp is utilized for the vacuum of the contacts as well. The size of the armature is made as light and small as possible not only on account of the general law of all mechanical construction, viz: make moving parts as light as is compatible with strength so that the position of the lamp will have no effect on the incandescence of the filament, but to minimize the amount of residual gas in the metal composing the armature, as any foreign gas will be detrimental to the filament. In Fig. 4 a socket of ordinary dimensions is shown constructed on the same principle. A socket of this kind can be adjusted to regulate a lamp of almost any C. P. within limits. In both of these instances the movement of the magnet pro duces the regulation, but it is evident the result would be the same by either the movement of the vacuum or the core of the magnet, as shown at A, or by throwing in and out coils of the magnet. The filament emits continuous light with an illuminating power corresponding to the rate of vibration of the armature. When the armature is not within the inductive distance of the magnet, it is at rest and the filament being in circuit, the light is at its maximum. An attachment to the means for adjusting the magnet is used to break the circuit when it is desired to |