Motion Picture Herald (Oct-Dec 1932)

40 MOTION PICTURE HERALD November 19, 1932 TECHNOLOGICAL ''''ill The BLUEBOOK School By F. H. RICHARDSON BLUEBOOK SCHOOL QUESTION NO. 1 50. — (A) Explain just how two and three-phase current is produced. (B) How is two-phase usually transmitted? Three-phase?, In this we refer to the wiring. (C) Should you attach a wire circuit half a mile long to a one-volt battery, the wires completely insulated from earth and from each other, would they show one volt of pressure at any point of their length? (D) Suppose you connect the positive of one battery or dynamo to the negative of a second one of similar characteristics and voltage, what would such a connection be called and what would be its effect? Suppose you connect the two negatives and the two positives together and connect the combination to a circuit. What is the combination called and what would be its effect? Answer to Question No. 143 Bluebook School Question No. 143 was: "(A) Can you offer any illustrative proof that something does actually pass from one point to another when current 'flows'? (B) Docs electric current seek to pass into the earth f (C) If you say that current generated by a dynamio has no affinity for the earth, explain why it often leaves the wires and flozvs into earth. (D) Explain, in your own words, just zultat takes place ivhen current finds a path and passes from negative to positive." The following submitted acceptable answers : G. E. Doe, Lester Borst, T. Van Vaulkenburg, C. Rau and S. Evans, Stanley G. Williams, "Bill" Doe, J. Wentworth and W. Sellers, D. Goldberg, P. H. Bondom, T. Davis and L. Lambert, J. L. Cooney, J. G. Evans, S. G. Williams, L. Davis and T. Tinlin, T. L. May and L. Bolles, W. Broadbent, T. Turk, J. Cermak and G. Fairmann, A. L. Patry and D. M. Devoy, D. Lode, B. Diglah and B. Jackson, K. L. Knight, S. N. Glasmon, F. Tinlow, B. L. Ledbetter, D. B. Burt and D. L. Sinklow, H. B. Coates, S. Peters and T. R. Peters, F. C. Hagmyer, M. Y. Thompson and D. O. Childres, D. Mason, B. H. Thomas, D. R. Mazzuca, P. T. Andrews and G. Blair, R. J. Rinker and G. Haddon, C. Tamper and L. Rond, L. B. Sanders, L. Garling, F. Ferguson and B. Williams, L. H. Pickard, B. T. Roberts and H. Gegeson, C. Tamper, D. L. Manuels and W. Sellers, P. L. Toeping, T. O. Thumb, C. Ray, G. Adams and B. Little, T. Lavenburg, A. Gibson, D. L. Sampson and D. L. Habe, R. H. Benson and A. Sidleburg, C. Peters, L. G. Sanburn and J. Sanborn, F. T. Gurbey and T. F. Brown, L. R. Daniels. N. L. Daniels, H. F. Franks and J. Williams, F. L. Langdon, B. D. Webber and L. Loughlin. H. B. Edwards, D. L. Simmons and P. K. Rontor, M. L. Kindrew, M. D. Dove, H. Sicmann, G. Westmore, P. D. Thompson, S. T. Jones and L. C. Abernathy, T. Garling, A. Zerach, L. R. Timson and B. Mitchell, J. G. Gates, T. NEW ADDRESS OF F. H. RICHARDSON All correspondence concerning the Bluebook School should be addressed, until further notice, as follows: F. H. Richardson, No. 3 Tudor Lane, Scarsdale, N. Y. L. Danby and F. D. Tollman, R. Rathbrun and G. Biglow, F. B. Gamble, R. Michels and D. Lode, T. Davis and T. Richards, M. T. Farrell, G. T. Stanhope, R. L. Myers and T. L. Cullen, D. Hendershot, B. Hodson and E. M. Johnson and S. G. True. With compliments to Messrs. Rau and Evans, Lester Borst, G. E. Doe, S. G. Williams, T. Van Valkenburg and W. Broadbent for their excellent answers to Section A of the question, the answer of J. Wentworth impresses me as perhaps best. He says : "Let us assume an electric dynamo at X. and 110-h.p. motor at Y, at a distance of 100 feet from the dynamo. Current (e.m.f.) is applied to the motor, which pulls a machine requiring all its rated 100-h. p. capacity. "I believe we may stop right here and admit the fact that something has actually passed over, or through, the conductors connecting the power generating and the power-using source as proven, since it is not within the range of reason that such an amount of power, or power in any amount, for that matter, can be conveyed 100 feet, or any other distance, greater or smaller, unless something conveys it. There is no disputing the question that power has passed through or over those wires, so how may we reasonably dispute or even question the fact that something has passed through or over them? Just by what this power is conveyed is a matter now in dis pute. But the very fact that power is conveyed is illustrative proof that something does pass or travel from one point to another. I repeat : power does that very thing." (B) S. G. Williams says, "Electricity does not seek to pass into the earth unless it (the earth) offers a path or conductor by means of which it may reach the opposite pole of its source, the generator. (C) T. Lavenburg says, "Electricity generated by a dynamo or a battery has no affinity for earth, except that it offers a path of sufficiently low resistance between points on conductors of opposite polarity attached to the generator, so that the voltage of the system may force the current over or through that path. Such grounded points may be close together or separated by considerable distance. If the points be near together, but by reason of dry earth or for some other cause, the resistance is high, little current will flow. It will constitute merely a 'leak'. Even though the points of grounding be far separated, but if by reason of water pipes, gas pipes or earth of high conductivity, the total resistance be low, the current flow may be heavy — even heavy enough to constitute a near approach to a 'short'. It is not a matter of length of the path offered through the earth, but of the resistance that path offers and the voltage of the system. (D) We will listen to Rau and Evans on this one. They say, "When the electric current finds a path and passes from positive to negative, pressure is consumed, and thus power is generated, which if directed intelligently, may be employed in useful work. The device through which the work is made manifest may be a lamp, by means of which light is produced; a motor, by means of which pulling power is made available, or a resistance coil used for heating purposes. If the power be misdirected, it will still do work, most likely made manifest in the form of useless and perhaps dangerous heat."