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.
802 HANDBOOK OF PROJECTION FOR
and adjustment of the G. E. lamp apply equally to the Power's improved lamp. Mention might be made here, however, of the method for removing the positive contact blocks from the sheet metal holders for the purpose of cleaning or replacing these blocks. To remove the contact blocks, take out the two compression springs, HT-204 Fig. 304, and bring the lower ends of the sheet metal contact block holders, HT-56 (Fig. 305, together at their lower ends, which will disengage the upper ends from the supporting pins. Once the holders arc free from the supporting pins the connecting link adjoining the two holders can be removed, though each holder will still be connected to the lamp by the contact ribbon attached to the contact blocks. To remove this ribbon, take out the contact block clamping bolts, HT-52 S Fig. 305, remove the ribbon clamping block, HT-52 A, and the end of the contact ribbon will then be free from the block, which block may now be pulled out of the sheet metal holder and new block inserted, following the reverse procedure for reassembling to the lamp.
OPTICAL SYSTEM AND CRATER DISTANCE.— The
optical system to be used and the principal constants are as follows : Condenser combination should be a 6j4 inch focal length plano-convex collector lens and a 9 or 9^4 inch focal length piano convex converging lens, the latter preferably five (5) inches in diameter. The collector lens should have the standard diameter of AJ/2 inches. Condenser lenses should be placed with their convex surfaces together and as close together as is possible without actual contact. A screw adjustment is provided for spacing.
NOTE. — The foregoing is manufacturers recommendation, with which we do NOT agree. We recommend that Griffiths lens chart be used, which may be done by adding one inch to the crater distances therein supplied.
The condensing lens mount as a unit should also be adjustable vertically and laterally, in order that the condensers may be properly placed on the optical axis, and the spot properly focused upon the aperture plate. The lamp should be mounted so that the center of the positive carbon is parallel to and exactly upon the optical axis, after which the lamp should be locked in this position, and the only adjustment then necessary is one through which the lamp may be moved laterally to and from the piano surface of the collector lens.
INTERCHANGEABILITY OF PARTS.— The positive contact holders and ribbons used in the Power's Improved lamp