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.
CURREN1 RECTIFICATION 293
light metal vane closes the 110-volt circuit through the mercoid switch.
The circuit continues down, across the bottom of the drawing and up to the magnet coil shown just to the left of the three-blade, three-phase input switch, and then back across the bottom of the drawing and out at the lower 110-volt wire.
Consequently, when the external 110-volt switch is closed, the sequence of operations is : the fan starts : the fan breeze closes the mercoid switch; power is supplied to the magnet of the three-phase switch, and that switch closes and supplies 3-phase power to the rectifier proper.
In addition to closing the mercoid switch, the breeze from the fan keeps the copper oxide stacks cool, and this is its chief purpose. Should the fan fail for any reason whatever, mechanical or electrical, or should the power of its breeze decline below the safety point, the mercoid switch will open, the three-phase swatch magnet coil will no longer receive power, the three-phase switch will open, and the operation of the rectifier will stop until repairs are made.
This arrangement, while providing an invaluable precaution, makes the operation of the arc lamp supply entirely dependent upon a single electric fan, and consequently an ordinary electric fan is not used, but one especially designed for long life and unfailing operation, and far heavier in construction than an ordinary fan of the same rating. In practice these fans give no trouble, and copper-oxide rectifiers of this type are commonly installed in cellars and other remote places where they receive very little attention.
The input circuit to the rectifier proper is to the three primary windings of the power transformer, which are delta-connected, and tapped to provide proper arc current from either 210, 220 or 240 line volts. The design of the transformer core is such that excessive current cannot be drawn while striking the arc. The three secondaries are also delta-connected, and provided with "aging" taps, for this reason: The copper oxide units deliver somewhat more than their rated output during