Kinematograph year book (1944)

Film Exhibition and Kinema Technique. 211 The company has succeeded in maintaining its high standard of servicing in spite of war time difficulties, and has been much assisted in this direction by the reliability of its product. Nevelin Electric Co., Ltd. — The makers of the Nevelin rectifier, which before the war was achieving a useful reputation among kinema users, have been engaged principally on war work. Their research workers, however, are working along certain interesting lines of development of their apparatus which will be available after the war. Runbaken. — With over 30 years' experience behind them, Runbaken, of Manchester, are in a position to supply metal rectifiers for projection ar^s which afford absolute reliability. The firm also specialises in the conversion of valve rectifiers to metal. Strong Electric Co., Ltd. — The Aldrich inductor is now installed in over 300 kinemas at a cost of about £30 each. They operate satisfactorily on all types of arc lamps, although the coaxial type of arc lamp offers the best screen illumination. The angular type of arc, if the angle is not too acute, will also give quite good, evenly distributed light. As there are no valves or other breakable parts in the Aldrich inductor, very many years of good reliable service may be expected. The equipment is essentially simple, and the installation calls for no high degree of engineering skill. An equipment is required for each projection arc lamp, so that each inductor may have a period of rest whilst its opposite number is in action. In the most unlikely event of one of the inductors breaking down, the remaining unit will operate both projectors for an indefinite period. The general efficiency of the x\ldrich inductor is in the neighbourhood of 93 per cent., and the consequent power factor is also high ; the maximum demand charge called for will therefore be correspondingly low. In many kinemas the maximum demand has remained at under two kilowatts for long periods, only increasing when both arcs have been left in operation at once for a sufficient length of time to register the increase. This can easily be avoided, and is, in fact, due entirely to careless operation. The light from an A.C. arc at 80 amperes is comparable with that provided by the modern H.I. arc lamp operating at 45 amperes D.C., but the high efficiency of the A.C. equipment provides this illumination at a cost of less than a third of that of the D.C equipment. Westinghouse Brake and Signal Co., Ltd.— Although present war demands still preclude Westinghouse from taking any very active part in the manufacture of kinematograph equipment, the firm's technicians have been so well pleased with the extremely satisfactory performance of the constant current projection arc equipments which were supplied before the war, particularly the small amount of service they have had to provide even in spite of relatively non-skilled projection staffs operating during the war period, that production of these equipment will be resumed as soon as opportunity arises. Meanwhile, development work with regard to the rectifier itself has been progressing and the new " Westalite, ' ' which makes use of the properties of selenium, has been perfected for the post-war market where the larger power applications are concerned. By the use of special selenium alloys Westinghouse has overcome the disadvantage of the copper-oxide rectifier which must be operated under 55° C. total temperature, and has evolved an element which can be worked satisfactorily up to a temperature limit of 85° C. with an efficiency at least as high as copper-oxide. This and other improvements in the Westinghouse range will result in even higher overall efficiencies than before and perhaps, most important of all, will result in still smaller overall dimensions of the equipment. EMERGENCY LIGHTING EQUIPMENT MANY kinemas have suffered during the recent intensification of airraids, and where these have occurred during a performance, the one reason of the absence of panic has been the efficient functioning of the secondary lighting equipment relying for its current on the storage battery. Many