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.
156 RICHARDSON'S BLUEBOOK OF PROJECTION
slightly softer than others, and thus tend to wear down faster, causing sparking and a roughened surface. The remedy is resurfacing in a lathe.
Hot Brushes
(90) Too much heat in a brush indicates a misplaced brush or a poor contact. The brush is heated either from poor contact within itself, or because the other brushes in the same line have poor contact and carry practically nothing, throwing the whole burden of carrying the current upon the hot brush. Examine the brush contacts and the brush pigtails. Remember that nearly all brush deficiencies produce heat.
Low Bearings
(91) This has been mentioned before, but is again referred to because worn bearings will, at least with some types of machines, throw the magnetic field sufficiently out of balance to cause sparking at the brushes. Here the air gap at the top of the armature will exceed that at its bottom. The gaps should be made equal. New bearings are indicated.
"Shorted" Coil
(92) A short-circuited armature coil puts the generator out of business promptly. The "shorted" coil will heat up quickly. The short may either be in the coil itself, or at a connection between two commutator bars.
Bent Armature Shaft
(93) A bent armature shaft is evidenced by increased vibration. It is unwise to attempt to have it straightened. A new shaft is the only reliable remedy.
Overload
(94) Overload causes the whole armature to develop excessive temperature ; it also causes brush sparking that cannot be stopped, though it can be reduced by shifting the brush yoke slightly from its normal position.