We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
352 MOTION PICTURE HANDBOOK
commodate the full amperage capacity of secondary fuses. Line 2-2 should not be less than No. 6 B. & S., and it would be still better to have them No. 4, because it may become necessary, in case of breakdown or for some other reason, to remove the transformer and substitute a rheostat, in which case you would not want to pull less than 50 or 60 amperes, and No. 6 R. C. is only rated at 50, No. 5 at 55, and No. 4 at 60 amperes.
The ordinary procedure is to install wires 2-2 just large enough to carry the secondary capacity of the transformer, but, for reasons already set forth, this is not the best practice. If wires 4-4 and 6-6 are rubber covered, then No. 4 must be used, since practically all transformers (economizers, compensarcs, inductors, etc.) have a 60 ampere secondary capacity, but if wires 4-4 and 6-6 are asbestos covered, they come under the weatherproof rating, and No. 6 is large enough, since No. 6 weatherproof is rated at 70 amperes. Wires 8-8, from machine table switch to lamp, must be asbestos covered stranded No. 6, unless a special transformer delivering more than a 70 ampere secondary current is installed, in which case they must be large enough to accommodate the current. Fuses 1-1 are merely designed to protect wires 2-2 and the transformer primary coil, but inasmuch as No. 6 wire will accommodate nearly three times the primary current capacity of the transformer, they really, in effect, protect only the transformer primary coil, and for the ordinary economizer delivering a maximum of 60 amperes at the arc, they should be 30 ampere capacity. Some transformers will deliver more than 60 amperes secondary, especially if the voltage be a little higher than rated, but you will -find that 30 ampere fuses will meet all requirements. The secondary may be fused to 65 amperes, which will give a 5 ampere leeway. But, however, if 65 be found insufficient, no harm will be done by installing others of 70 ampere capacity.
The reason for requiring fuses on the secondary as well as on the primary are twofold; First, some operators and managers locate the transformer outside the operating room, even putting it down in the basement. This is very bad practice, but nevertheless they do it, and then, exercising still more and greater bad judgment, stick 50 or 60 ampere fuses on the primary. The inspector is not likely to see it, because it is an out of the way place. For practical purposes they may just as well not fuse at all, because with 110 volt transformers, 60 ampere primary fuses would deliver about 150 amperes on