International projectionist (Nov-Dec 1933)

GREATER EFFICIENCY WITH PRESENT D. C. ARCS Joseph E. Bliven MEMBER I. A. LOCAL UNION 439, NEW LONDON, CONNECTICUT IF the direct current arc light is properly stabilized by the injection of proper chemicals and earth oxides in the carbon to the extent of creating a greater overall efficiency per watt input, I believe that a greater incandescence can be had and a more brilliant white light obtained. The electronic flow could be directed in a more concentrated manner, either by creating a greater electro-magnetic or electro-static field around the carbon in such a way as to cause the electrons to be driven against the positive carbon tip, causing the terriffic impacts to bombard the carbon into a white incandescence, thereby utilizing not only the regular gaseous ball between the electrodes but directing the tail flame to a more useful purpose. The chemicalization of carbons would occasion a more useful life and insure a greater lumen factor per watt input. If this work were intelligently handled by both the carbon people and lamp manufacturers, we ought to be able to get as much and as good a light at 75 amperes as we are now obtaining with 150 amperes. Incidentally, it is my personal belief that we are not now getting a watt lumen output that can be compared on any rational basis with the cost. Some years ago I utilized with direct current a combination of regular cored upper carbon (positive), and the special A. C. white flame lower carbon as a negative in a vertical lamp. The difference in illumination between this combination and the conventional one was astonishing. I secured a brilliant white light with a sharpness of field which matched the results obtained in the recent demonstration before the S. M. P. E. of the new National A. C. carbon. I have been told that I must be mistaken regarding the results of my little test, but the quality and quantity of light produced was the best answer to these critics. Mr. F. H. Richardson can verify the results of this test, if he recalls the details, as he described it .at the time. While I do not have the facilities necessary to engage in extensive lest work of this kind, I maintain that a concerted effort by the carbon people and the lamp manufacturers in the direction outlined above would obviate the necessity for even considering the replacement of any D. C. arc now in use. Consideration of the appended article relative to the electron flow as applied to arc lamps sets forth my theory of the action of the arc. Electronic Crater Formation I have heard and read considerable comment on the crater formation of carbon arcs, a majority of which explanations are satisfactory. I do believe, however, that this action may be explained more thoroughly, and this I shall attempt to do in this article. The crater of a carbon arc is due to the electron flow, and the electron flow is proportionate to the intensity of the volatilization and the induced voltage. The electron stream is directed at the core of the positive carbon because of the magnetic deflection of the surrounding atmosphere. To those who doubt the accuracy of this statement, I suggest that they try an arc deflection with a magnet. If retained, and the magnet be strong enough, it will blow out the Thank You! International Projectionist 580 Fifth Avenue New York, N. Y. Gentlemen : Enclosed is my subscription renewal for I. P. I am glad that your renewal notices arrive in ample time to prevent the loss of a single issue, which I feel could not be replaced for several times your subscription price. I have benefitted more than words can explain by the monthly visit of LP., and I have preserved every issue since Vol. 1, No. 1 as a valuable craft reference. Unquestionably you have many others on your list who feel the same way about LP. as I do, but if there are any projectionists who have yet to be introduced to LP., that is their loss. When I wish you a long and useful life I am voicing the sentiments of hundreds of projectionists in this territory. Sincerely yours, Charles J. Keeler Waco, Texas arc, due to the forcing of the electrons in a wider radius. Also, many projectionists will recall the trouble occasioned with some lamphouses with a deflected arc resulting from the magnetic properties of the lamphousings. Checking the electron flow, we find that the propagation is proportionate to the charge; in other words, the force of the electron is regulated by the magnetic field intensity X (times) the charge X the velocity, and this velocity is governed by the e. m. f. at the arc, the result being a disassociation of the electron from its atomic nucleus. Electrons in an arc do not under ordinary circumstances go straight from tip to tip but describe a curvature, and the radius of this curvature is equal to the mass X (times) velocity X the intensity of charge. We see, then, where the deflection of arc electrons is really sustained by a certain curvature, because carbons placed vertical to each other do not as a rule get as incandescent as those placed somewhat out of line. This is due, I believe, to the fact that the electron is shot past its target or hits the carbon shell above the crater depression and thus causes small incandescent globules on the side of the carbon. If. shortly after this condition is noted, the carbon is carefully examined, there will be found on the shell small pits or holes — which condition, if permitted to spread, ultimately will result in a complete disintegration, or needling, of the carbon. All projectionists have noticed in high intensity arcs that the radius of the arc stream from the negative to the positive (the displacement of the negative is to cause less light emission interference), is proportionate to the induced e. m. f. and to the magnetic deflection. This being so, a thermal control is easily utilized so that any change in the magnetic deflection, the result of carbon consumption, automatically brings relays into action and speeds up the feed. Now, if the electron flow is projected with a certain velocity, and the angle of projection is in a certain direction, then (Continued on page 32) [23]