Proceedings at the Convention Volume 21

Proceedings at the Convention Volume 21

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 edition. Excerpt: ...14 shows a very high degree of uniformity and lamps of high efficiency. The average candle power is very close to rating and the efficiency is somewhat better than rating. The lamps range in candle power from 14.8 to 16.8 and the watts from 49.95 to 55.8. Life Test The twelve lamps of each lot that were operated on the life test were selected as closely as possible to the rated candle power and efficiency. This careful selection of lamps grants an advantage not due them to the lamps that were poorly selected at factory, and undoubtedly shows more uniform results on the life curves than if they were selected at random. It is difficult to see, however, how more erratic performance could be obtained than is shown on some of the curves presented, even though lamps be taken at random. Readings of each lot were taken at 25, 50 and 10o hours and at the expiration of each 100-hour period and thereafter, up to and including 1,500 hours, 'the regulation of pressure on the bank of lamps was well within one per cent and lamps were operated at normal rated voltage. In taking the candle-hour measurements a maximum of one-half candle rise from the initial was read, thus cutting off the peak of freak curves showing an abnormal rise in candle power. The candle-hour area was determined to the 80-percent limit and a separate reading was taken from the 80-per-cent limit to the 1,500 hour mark, or until the burning out of the lamp. These separate readings are tabulated in Figure 32. The candle-hour-area readings from the life curves were taken by means of a Crosby planimeter, which was accurate within one part in one thousand. Candle-hour readings were taken of each individual lamp of each lot. The life curves for the various lots are shown in Figures 16 to...show more

Product details

  • Paperback | 182 pages
  • 189 x 246 x 10mm | 336g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236938801
  • 9781236938800