Moving Picture World (Jan-Mar 1914)

8o4 THE MOVING PICTURE WORLD Projection Department Conducted by F. H. RICHARDSON Operators* Union Directory, I. A. T. S. E. NOTICE: — Each union is entitled to have its roster of officers, meeting nights, etc., listed here once per year free of cost. Preserve this list as it will not be republished. The mail address of the secretary should be included, and address of regular meeting place, if any. Local No. 173, Toronto, Ontario, Canada. Clarence McMahn. President; William Taylor. Vice-President; George F. Eaton, Secretary; 6S0 Ossington Avenue; Lindsey McCracken, Treasurer; William Winslow, Sergeant-at-Arms. Meetings held first Sunday in each month in Labor Temple. Important Notice. It is impossible to reply to letters through the department in less than two weeks and sometimes three. In order to give prompt service those sending 4 cents in stamps to cover the cost of same will receive a carbon copy of the department reply by mail. Those desiring the full list of •questions, now running in the department, may obtain same by remitting 25 cents to the editor. Question No. 19. Best answer will be published and the names of others sending in replies of excellence will appear in the Roll of Honor. Explicit permission to use •the name must accompany each answer, otherwise only the name of the ■city will be used. Suppose your tnolor-generator ran Une for a time after installation but presently the brushes begon to spark and a black tnark appeared on either side of the commutator, directly opposUe to each other. The trouble spreads quickly to include about one quarter of the coinmutaior and the generator will not pick up its load, or if it does the brushes flame badly. We ivill assume that lb rushshifting has been tried and the armature tests out clear, so far as shorts and grounds are concerned. What is the trouble and its remedy^ How does a shorted shunt field coil on a compound zvound generator affect the other field coils? Wliat general effect does it have on the generator.^ Roll of Honor. There was a small basket full of replies to question 13, but a large percentage of them were really replies to question 12. This was the editor's fault, since the two questions, to a considerable extent, covered the same ground. I have had one awful struggle with these questions. It looks simple until you tackle it, but a football skirmish is a joke by comparison. To first select just those questions which are best calculated to serve the purpose in view, to word them in the best possible way and then to keep one from overlapping on another is one great big job, believe me. The Roll of Honor for this week is as follows: Harold Weiss, Battle Creek, Michigan; E. L. Rawlins, Eagle Pass, Texas; Chicago, Illinois (4), three answers by members of L. U. No. 2; Philip Glaser, Lancaster, Ohio; Toronto. Canada; Clarence Dowsley and L. S. Usher, both of Winnipeg, Canada; W. S. James, Camden, New Jersey; L. C. LaGrow, Albany, New York; Ernest Wills, Brookings, South Dakota; Cleveland, Ohio, (4); C A. Webster, Cameron, Missouri; Joseph R. Aaron, Calgary, Alberta, •Canada; Fort Worth, Texas (2); New Orleans, Louisiana; Lee Kelley, Ft. Flagler, Washington; Denver, Colorado; Tacoma, Washington; Henry Joesten, Brooklyn, New York; St. Louis, Missouri (2); Joseph L. Waldook, Brooklyn, New York; Robert D. Marshall, Wilmington, North Carolina; ^t. Paul, Minnesota, and Los Angeles, California. Answer to Question No. 13. By "Commutator," Washington, D. C. I The question: li'liat care should be given to a comtnutertor and ivhat is the best evidence that it is in Ai condition? Explain what troubles the. commutator is liable to and how you would remedy each. The Answer: The best evidence that the commutator is in Ai condition is a sort of glazed appearance, smooth as glass, a brownish shade in color and a slight squeak from the carbon brushes when the armature is revolved slowly. To obtain and maintain this condition the following care must be given: (a) That the brushes are kept set as nearly as possible at the «parkless point, and this point may vary with the load. (b) That the brushes have just sufficient tension to make good electrical contact with the commutator, remembering that every particle of unnecessary pressure will tend to wear both commutator and brushes unduly, and 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 once 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 six inches square, fold this so that it is two inches wide by six long, which will form a pad with a face of one thickness, backed by two thicknesses. Next open up your pad and smear a little vaseline on the center section, which is the back side of the face of the pad, after which re-fold the pad and it is ready to 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 dropping 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 must never, never, never be used on a commutator. If one application as above every six hour's run does not suffice, then it is likely that; (i) your brushes have too much tension, (2) your machine is overloaded, (3) your brushes ' not properly set, or (4) there is some other trouble. (See reply to question 12.) Never use gasoline or benzine around a commutator as it is likely to attack and sofen the shallac and insulaion and set up serious trouble. (d) That sufficient oil, or combined oil and carbon dust, has not collected at any point or spot, either on the commutator or face of any brush, to form a semi-insulation. (e) That there are no high bars, low bars, etc., and that the commutator is perfectly round. (See reply to question 12. Ed). (f) That a fragment of copper does not drag across the insulation between two adjacent bars, or that oil and carbon dust does not form such a bridge. (g) That the brush springs do not carry sufficient current to heat them. (h) That the brushes fit properly in their holders and are kept free from accumulation of dirt, dust, etc. (i) That the brushes are neither too hard or too soft. (j) That the armature "floats" slightly — i. e., has from 1-16 to M inch end play, according to size of machine. This tends to prevent the brushes cutting grooves in the commutator, (k) That the copper and mica insulation wears down evenly. (1) That the generator is not overloaded and that there are no other faults present which would tend to cause unnecessary sparking or otherwise injure the commutator. As to remedies, I think question No. 12 took care of that end of things and that you have inadvertently overlapped the two so that extent, therefore, I will dock the ship, put out my headlight, put the reels away and retire to dream that by happy chance I shall see my name, or at least (thanks to that r-o-t-t-e-n "law") my nom, de plume, on the Roll of Honor in due course of time. On the Map. Messrs. Francis Fox and Melvin Cummings, Hillsdale, Michigan, by their combined efforts have accomplished the following: As we have seen nothing in our department from Hillsdale, we wish to let you know that this little city is on the map. I have been operating three years, and Brother Fox, who is writing half this letter, has been struggling with a crank for an equal period of time. Projection here is good and we are trying to learn everything possible. After reading the Handbook until the type turned red, we ask the following: In an issue of May, 1913, there is a diagram for an oil tight casing which encloses the geneva moveiment, but we do not understand it and would like you to give more detailed information. I can see by your letter that both of you really have been operating just three years, because one-half of the typewritten letter is precisely as good as the other half, therefore, your ability must be equal. Signed: Sherlociko, the Editor. As to the oil casing in question: It was illustrated on page 485, May 3, 1913, issue. The thing is simple enough. Brother Klink, Canton, Ohio, made a new cam and intermittent sprocket shaft for his Edison machine, and made them long enough so that they extended out on the left hand side of the machine a sufficient distance to allow of the cam and star being placed on the end of the shaft outside the mechanism. He also put them on the shaft in reversed position, that is, pointing the other way. He also removed the left hand bushings from their present position and put them in a separate bearing, as shown. I think this should make it clear to you. Remember that the cam and sprocket have been taken out of their present position and put on the extension of the shaft on the outside of the left hand side of the machine. That is probably what puzzled you. Possibly Brother Klink will write you and explain matters more fully. The address of Brothers Fox and Cummings is either the I. X. L. or Mantauk Theater.