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.
424
HANDBOOK OF PROJECTION FOR
In other words, instead of 2-ohms resistance opposed to th3 voltage, as would be the case if we had but a single rheostat, 4-ohms resistance is opposed. Disregarding the resistance of the arc, if the supply current were 110 volts and we had but a single 2-ohm resistance rheostat connected in there would be a resultant current flow of 110 -* 2 = 55 amperes.
ffccr-s
r c?o#/y /p//fosr/?r
+
Figure 134.
If we now connect another 2-ohm rheostat in series as per Fig. 134, we will have 4 ohms opposed to the current, and, again disregarding the arc resistance, we would as a result have 110 -* 4 = 27.5+ amperes current flow. Please understand clearly that this would not be the result of the connection shown in Fig. 134, because in addition to the 4 ohms opposed by the rheostats there would be the resistance of the arc added thereto. In the above we are merely showing you the way the thing operates — not working out accurate results. The actual total resistance of such a combination, including the arc, would be about 5 ohms, hence the actual current flow 110 -* 5 = 22 amperes.
MULTIPLE CONNECTION.— The multiple connection is one which puzzles many, yet it is a very simple matter, once one gets a clear idea of the principles involved.
Fig. 135 is the diagrammatic representation of a water main, A, connected to the supply pipe B of a motor by means of two small pipes in which valves C-D are installed.
\
t
4
& "Blrtrr** Aforo*?. —+ f
Figure 135.