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.
FOR MANAGERS AND OPERATORS 373
tating pole is used and the manufacturer marks the point at which the brush yoke should be set by making either a chisel or center-punch mark on the yoke and on the frame. Some manufacturers fill these marks with white paint so they are very easily seen — some do not. Where these marks are present the brush yoke should always be set so that the marks on the frame casting and the yoke coincide, or, in other words, are opposite each other!
(b) The brushes must have just sufficient tension to make good electrical contact with the commutator, remembering that every particle of unnecessary pressure will tend to unduly wear both commutator and brushes, and to groove the copper unless the armature has a little end play.
(c) That the commutator be kept clean and free from dust. This may best be accomplished by cleaning the whole machine every day, blowing the dust out from around the field poles, etc., with a bellows, and last of all, wiping off the commutator with a canvas pad made as follows: Cut a piece of ordinary canvas 6 inches square, fold this so that it is 2 inches wide by 6 inches long, which will form a pad with a face of one thickness, backed by two thicknesses. Next open up the pad and smear a little vaseline on the center section, which is the ^back side of the face of the pad, after which refold, let lie 'a few hours in a warm place, and it is ready for use. Sufficient vaseline will gradually soak through the pad to give the commutator all the lubrication it needs, and that is mighty little. The foregoing 'holds good in summer, and in winter, too, if the generator is located in a warm .room, but if, on the other hand, the machine is cold, then it will be well to moisten the face of the pad by using a few drops of a very thin oil on a piece of glass, spreading it around evenly and then wiping it off on the face of the pad, the idea being to get the oil evenly distributed on the pad. Remember this, however, too little lubrication is better than too much, and heavy lubricants (thick oils) must never, never, NEVER be used on a commutator. If one application as above every six-hour run does not suffice, then it is likely that, (1) your brushes have too much tension, (2) your machine is overloaded, (3) your brushes not properly set or (4) there is some other trouble. Never use gasoline or benzine around a commutator; it is likely to attack and soften the shellac and insulation and thus set up serious trouble.
Caution. — Where the mica insulation of the commutator is undercut great care should be taken in regard to the lubricat