International projectionist (Jan-Dec 1945)

GOOD RESPONSE ABROAD TO RCA's THEATRE EQUIPMENT PROGRAM Active interest is being demonstrated by theatres in overseas territories in RCA's program for a complete line of theatre equipment, according to Karl Streuber, manager of the newly consolidated theatre and sound equipment department of the RCA International Division. He declared that since the first announcement of plans for the program there has geen accumulated marked evidence of a world-wide demand for new theatre equipment, both for mod-" ernizing existing theatres and for building new ones. "RCA's plans to provide theatres with projectors, generators, screens and other equipment," Mr. Streuber added, "as well as RCA sound systems, have been in step with this demand and have been welcomed by distributors abroad. "Our expanded program of distribution is itself the fulfillment of a demand from theatre owners, dealers, distributors, technicians and manufacturers in many parts of the world. The established lines which we have grouped into one family of products permits the extension of RCA standards to cover the entire field of theatre equipment." He aso pointed to the fact that motion pictures during the war "have demonstrated their remarkable versatility on the home front as well as in training areas and in the battle zones." the wave. As the coil rotates in a uniform magnetic field, it cuts a certain amount of flux depending upon its position in the magnetic field. The amount of e.m.f. generated in the coil depends upon the amount of flux cut by the coil at any given time. This e.m.f. is zero when the plane of the coil is perpendicular to the field and reaches a maximum value when the plane of the coil is parallel to the field. The wave shown in Figure 2b is known as the sine wave. It is so called because the value of e.m.f., which is generated at any instant, is proportional to the sine of the angle which the coil makes with a plane through its axis and perpendicular to the direction of the magnetic field. The wave shown in this illustration repeats itself periodically as the coil rotates in the magnetic field, and because it repeats itself in cycles, is called a cycle. One-half of this wave, the period during which the voltage varies from zero to a positive maximum then back to zero, is called an alteration. The period during which the voltage varies from zero to a negative maximum then back to zero is also known as an alternation. We see, therefore, that each cycle contains two alterations. All sine waves have this characteristic. (The term "sine" is a trigonometric function and will be thoroughly explained in a later article.) One alteration represents 180 electrical degrees, and one cycle represents 360 electrical degrees. In an alternating current generator having only two poles, one alteration will be produced when the coil makes one-half revolution or turns through 180 space degrees, and a cycle will be produced when the coil completes one revolution or turns through 360 space degrees. The number of cycles produced by a generator in one second is called the frequency. Thus it may be seen that the relation between space degrees and electrical time degrees in a two-pole generator is the same. This does not hold true for other types of machines. For example, in a four-pole machine one alteration will be produced when the coil makes a quarter of a revolution — that is, when the coil rotates through 90 space degrees it will produce a voltage wave which contains 180 electrical degrees. The coil will generate a voltage wave of 720 electrical degrees or two complete cycles when it makes one complete revolution. Speed, Poles, and Frequency A definite relation exists among speed, poles, and frequency. This relation is given by the following formula: PxS (1) F=— — . Where F is the fre 120 quency in cycles per second, P is the number of poles, and S is the speed in r.m.p. (revolutions per minute). When the frequency and the speed are known we may find the number of poles in the generator by solving the formula for P. The formula would then read Fxl20 (2) P= . When the frequency S and the number of poles are known the speed may be found by the equation F x 120 (3) S= . P Here are some typical examples. What frequency will be generated by a 6 pole alternator, running at 500 r.p.m.? Let us use formula (1) above. 6x500 F = = 25 c.p.s. (cycles per 120 second). A 60-cycle alternator is rotating at 1800 r.p.m. How many poles are contained in the machine? We will use 60 x 120 formula (2) above. P = = 1800 4 poles. MAY QUESTIONS 1. A 60 cycle, 8 pole, alternator is rotating at how many r.p.m.? 2. How many poles are contained in a 25 cycle, 180 r.p.m. alternator? 3. What is the frequency of an 8 pole, 900 r.p.m. alternator? The correct answers to these questions will appear in the next issue. WILL WHITMORE NAMED ADVERTISING MANAGER FOR W. E. Will Whitmore has been named advertising manager of the Western Electric Company, succeeding H. W. Forster, deceased, it was announced by F. B. Wright, director of public relations. Mr. Whitmore had been advertising supervisor. He joined the company in 1929 and has been with the organization continuously ever since. His work in the public relations department covered all phases of publicity, advertising and magazine editing, and his articles, especially in the field of popular science, have appeared widely in business, trade and photographic magazines. Mr. Whitmore for a number of years during the post-introductory phase of the talking motion picture development, specialized in the subject of sound films. He served as chairman of the publicity committee of the SMPE for nine years. Through his efforts many of the motion picture industry's more than 50,000 technicians gained their initial insight into the complexities of recording and reproducing sound on discs and films. Mr. Whitmore, a member of the SMPE, the Radio Executives Club and the Industrial Advertising Association, was born in Lockhart, Texas. 1944 SALES OF GENERAL ANILINE RISE 24.7% OVER 1943 Sales of General Aniline & Film Corporation during 1944 were $73,311,178, or 24.7 per cent more than the previous year, and the highest in the history of the company. Operating profit before taxes increased more than 25 per cent, to the record level of $16,984,637, comparing with $13,551,713 in 1943. Federal taxes on income also reached a new high level, totaling $12,123,000 in 1944 as compared to $8,989,267 in the previous year. The company reports net profit after taxes and provision of $1,000,000 for special accruals due to wartime operations at $4,813,276, or $6.57 per share of Common A stock. This is an increase of 18 per cent over the revised net profit of $4,062,527, or $5.54 per share of Common A stock in 1943. Excluding profit of $1,221,347 on sale of securities, 1944 net profit was $3,591,929, or $4.90 per share, as compared with $3,605,069 or $4.92 per share on a similar basis in 1943. FAZALBHOY OPENS N. Y. OFFICE IN RCA BUILDING Fazalbhoy, Ltd., India, has opened a New York office in the RCA Building, 30 Rockefeller Plaza, Room 5028, according to an announcement by its New York representative, Allan E. Currimbhoy. The office was organized to develop closer contacts between the home offices of Fazalbhoy, Ltd., in India, and the prominent American manufacturers of motion picture equipment, whom Fazalbhoy. Ltd., represent in India on an exclusive basis. These include Simplex projectors and Peerless Magnarc lamps. 20 UVTERIVATIOIVAL PROJECTIONIST