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.
412
FRANK BEN FORD
[J. S. M. p. E.
in the visible region. The operating temperature of the glass is high, but necessarily less than quartz, and therefore the vapor pressure is lower and the brilliancy of the arc is less than in the case of the quartz lamp.
The starting and operating characteristics of this lamp are different from other lamps that are either plane arcs or plane incandescent and not a combination of the two. The lamp is best operated on a transformer with a magnetically saturated core . Upon closing the circuit the filament carries the entire current, which rises to between 7 and 10 amperes before the arc forms, which occurs about a second
30
~Job too *oo BOO /ooo
FIG. 9. Typical depreciation curves of Uviarc.
after the current starts to flow. In the case of the particular lamp of Fig. 10, the maximum current was 7.5 amperes at the moment of arc formation. The voltage was 18 volts, but this quickly fell to 10.5 volts when the combined arc and incandescent currents mounted to 30 amperes, which is the normal operating current. In Fig. 11 the solid lines were obtained by reading indicating instruments as the voltage was slowly changed and hence the record probably differs in details from an oscillograph of the normal starting characteristic. The dotted lines represent changes that took place too rapidly for instrument readings, but the real starting characteristic probably does not greatly differ from curves A, J5, and C.
At 30 amperes total current the division is about 25 amperes arc and 5 amperes incandescent, the latter being slightly reduced by the conducted heat from the electrodes raising the temperature and