Keep the Generator Clean and Properly Oiled
With All the Electrical Connections Tight
For Long, Trouble-Free Operation

NOTE:  Here is Wesley Trout's first article in Boxoffice magazine.  It appeared in The Modern Theatre Section of the January 5, 1952 edition.  Wesley would be the projection and sound correspondent for Boxoffice for nearly 26 years.

It is good to see in the construction of new theatres and remodeling of old theatres that more attention has been given to the construction and equipping of the "heart of any theatre" -- the projection room.  In my treks from time to time, I found projection rooms in small towns equipped with the very latest projectors, high intensity arcs, coated lenses, enclosed automatic rewinds, high fidelity amplifiers, soundheads of the very latest design, and general conveniences and appointments that made it a real pleasure for the projectionist to work with. Too, I noted, in most every projection room the projectors were equipped with electric changeovers which made smooth and quick changeovers.

At this time I am not going to go into detail regarding the size, location, sound and fireproofing of projection rooms, but to those contemplating remodeling or construction of a projection room in a new theatre, I shall be happy to furnish complete data.

On this page is a photograph of a modern, well-equipped projection room that I think serves as a good guide. I advise consulting local authorities regarding types of material and general construction of walls and ceiling.  Personally, I always have recommend hollow tile for its fine fireproof and soundproofing qualities. I urge every exhibitor to give careful thought when planning a new or remodeled projection room, so that it will meet all local and national requirements and perhaps earn a big saving in insurance rates when equipped and built right.

A well-illuminated projection room is of paramount importance. General lighting of the entire room should be of the indirect type; over each projector should be a light (with a shade, for threading projector, cleaning and oiling, etc. There should be light, properly shaded, over the rewind table and film cabinet. A drop cord of sufficient length should be kept on hand for making repairs on any of the equipment. Cleanliness in the projection room always indicates the projectionist in charge is a man of intelligence and has high regard for his work.

MAINTENANCE OF MOTOR GENERATORS

 If proper and intelligent care is given motor generator sets, they will give long and highly efficient service. The care of the commutator and brushes and proper oiling are of paramount importance. The commutator should be kept clean and never allowed to become roughened from lack of attention. Keep all wiring connections tight; brushes should fit the commutator correctly and be free from oil and dust—they should be neither too hard or soft but be the type recommended by the manufacturer. Do not put too much tension on brushes as this will have a bad effect on the commutator—it will wear the brushes and commutator unnecessarily and cause sparking sometimes. Brushes should have just enough tension to hold them firmly against the commutator and make good contact.

The commutator should be cleaned at least every week with a soft piece of cloth while the machine is running. If the commutator becomes slightly rough and needs smoothing down, use No. 00 sandpaper and hold on same while revolving. Now take a piece of canvas the width of the commutator and "brighten up" and clean the entire surface; next, take a stiff brush (machine not in operation) and brush out all the dust so the segments are clean. Start machine (be very careful, and take soft cloth and again clean entire surface of commutator, using just a little vaseline on a cloth. Don't drown the bearings with oil, and use only the lubricant recommended by the manufacturer.

Bear in mind that a dirty commutator (roughened surface), oil or dirty brushes, will cause sparking and improper setting of brushes. The commutator may need turning down in a lathe by a first-class machine shop. If the rocker arm has been moved, set the arm back or forward until sparking quits. The wrong type of brushes will also cause considerable trouble. I suggest that you consult the manufacturer, the writer, or your supply dealer and be sure you have the right type of brushes and lubricant. "True" direct current can only be had from a generator, and with proper care you should have very little, if any, trouble.

If you find a brush that does not fit the "curve" of the commutator correctly, you can fit it by placing a fine grade of sandpaper, the width of the brush and long enough so you can hold it on either side, with the sand side against the brush. Then slowly rock commutator back and forth (by hand, of course) until the brush has the right curve and fits the commutator correctly. This is a slow task sometimes, but it will give you a good brush fit and save the surface. This same method should be used when fitting new brushes to secure the proper curve. Be sure to clean well after you have finished so that no brush dust or sand is left on the surface or in the segments of the commutator. This would cause sparking and pitting of the surface. Check brush holders and see that the brushes work freely. If they don't fit right in the holders and stick, take the brushes out and with little emery cloth clean the inside until they work freely. Tension on all the brushes should be the same. An extra set of brushes should be kept on hand.

All generator sets should be mounted on a concrete base with cork under the "feet" to eliminate noise. I strongly recommend that generators for arc lamps be installed in an adjacent room as this will keep unnecessary noise out of the projection room.

If rectifiers are used they should also be in another room adjacent to the projection room. However, I have seen some nice installations with the rectifiers placed under or near each lamp, but this creates more heat in the room. The panel board (control box) with ammeter and voltmeter should always be in the projection room, a practice which is generally followed now.

Again let me emphasize, keep the generator clean, properly oiled and all electrical connections tight, and you will receive long service, and, in most instances, trouble-free operation.

While there are sprocket pullers and pin ejectors on the market. I had made by a machine shop, many years ago, the two illustrated on this page. They were made from bronze with the exception of the shafts that push out the sprocket or pins: the knob I purchased from a local typewriter shop.

As I stated above, there are sprocket pullers available and I am just passing these two ideas along to projectionists if they want to build their own or have a machine shop do it. The measurements are exact and such tools are very handy when replacing an intermittent sprocket. While it is best that the sprocket should not fit so tightly that it is necessary to use a sprocket puller, I have found many cases where I was glad I had these two tools in order to avoid springing a shaft, which is very easy to do.

Wesley Trout, an experienced projectionist and theatre manager, will be glad to answer questions and to try to solve problems which may be troubling men in the booth. Address him in care of The MODERN THEATRE, Kansas City, Mo.

January 5, 1952