The Film Index (Jul-Dec 1910)

IO THE FILM INDEX 31 IE ELECTRICAL TALKS On Electricity in Its Relation to the Motion Picture Theatre By J. H. Hallberg II II IE IE= =3E E3E Written Expressly for The Film Index. Copyright by J. H. Hallberg. All Rights Reserved. SUMMARY OF ELECTRICAL TALK NO. 13.— With a given system of electric mains running in front of a number of buildings, whether two-wire or threewire system, perfect results can be had if the voltage supplied to the mains is constant, the mains are of proper size, the transformer of proper size, and the load properly balanced between the "neutral" and each outside wire. "ELECTRICAL TALK" NO. 14. Electrical Service (Continued). In "Electrical Talk, No. 13," I referred to an installation for a motion picture theatre in building J, of figure 29, you will recollect, or by referring to the last talk, you will see that the load for this theatre consisted of the M. P. lamp and a number of incandescent lamps, which had to be connected for 110 volts, and that in order to give this voltage, the electric light company had to use the neutral and one outside wire if the three-wire system, and we also found that the system became unbalanced on account of this installation, which is, of course, undesirable for reasons which have already been explained to you. The inconvenience from variations in the voltage not only ef TO LINE LINE FUSES METER PANEL OR DISTRIBUTING BOARD Fig. 30 fects the operator in the M. P. theatre as his light is likely to be poor, but it also effects other consumers supplied from the same system. In many instances the electric light companies find it convenient to make such a connection, because it has to be made in a hurry, or they do not anticipate difficulties which might arise therefrom. A much better way would have been to supply the theatre J with current from a separate transformer, the primary of which could be connected to the high voltage primary line wires, and the 110-volt secondary transformer wires could then be connected to the two-wire service. This would overcome all the trouble, and there would then be no voltage drop due to unbalanced load on account of the M. P. lamp in theatre J. It is With a system as that described above, great troubles may be experienced if the voltage varies, if the wires are too small, if the transformer is too small, or does not regulate well, and if additional load is added without consideration being given to the proper balancing of the load and the necessary increase in size of transformer, mains, service wires, electric meter, switches and fuses. the aim of all electric-lighting companies under modern management to avoid the unbalancing of a three-wire system by putting in separate transformers and service for customers who have a load of such nature that it is likely to unbalance the system, but sometimes it becomes necessary for the manager or the operator of the M. P. theatre to register a kick about the drop in voltage when the M. P. lamp is switched on and the consequent rise in voltage when the lamp is switched off, and the sooner the electric light company is made aware of this voltage variation, and corrects it, the better lor all concerned. The Electric Service Within a Building. After proper mains have been brought into a building for the supply of electric current, a service switch with fuses of proper capacity must be installed as close to the entrance of the wires as convenient. The purpose of this switch is to disconnect entirely the electric current supply from the building at night, so as to insure perfect safety and also give the proprietor absolute insurance that no single lamp is burning which would cause the meter to register unexpectedly and unnecessarily. The electric lighting company will then install an electric meter of proper size, and the wires from the meter may then be run to an electric distribution panel, which must contain the necessary fuses and switches for the protection of the various groups of lamps, fans, motion picture machines, flaming arc lamps, spot lights, etc. The panel board referred to is usually located at a convenient point where the manager or other person in charge has full control of every circuit, permitting the turning on and off of the various circuits, and the fuses should be of proper capacity to protect the wires connected to the switches. The term "panel board" usually signifies a small switch board made of slate, upon which is mounted bus-bars to which the mains are connected, including also the proper number and size, switches and fuses which are connected to the bus-bars. The various circuits are then connected to the switches. Two-Wire Service. Figure 30 is a diagram illustrating a typical two-wire installation, including the following: Line fuses; Line switch: Meter; Panel board for 10 circuits. It is evident that in place of the panel illustrated, a cheaper form of distributing board can be constructed. For instance, in place of the board illustrated, there could be used a number of double-pole, double-branch, combined cutouts and switches mounted on the usual form of porcelain base as illustrated in figure 31. Wherever panel boards or cutouts are installed, they should be mounted in a suitable box, which should preferably be made of slate, or it should be lined with sheet iron and provided with a door lined with the same material, so as to make a practically fire-proof cabinet, and the door should be provided with a lock, so that outsiders may not have opportunity to interfere with the fuses or switches. No panel box is complete without at leatst one extra fuse for each circuit to be on hand in case of an emergency. A panel board should always be examined at frequent intervals to make sure that all connections are tight, also make sure that the fuse plugs, or any other form of fuse that are used, make good and perfect contact. The switches should occasionally be examined to see that the clips make good contact with the switch blade, and a little vaseline or flaked graphite applied to the clips will prove advantageous and will increase the life of the switch, also insuring better operation. FUSES [_ SWITCH TO CIRCUIT Fig. 31 Attention to these small details will oftentimes prevent trouble, and there is one thing you should remember, and that is that a loose contact or an overloaded wire, fuse or other connection always cost you money, because a loose contact or a small wire generates heat, and as this heat requires electric energy, it represents a useless expense, besides a loose contact will also lower the voltage to such an extent as to interfere with the proper operation of your installation. SUMMARY. Electric service within a building must be amply protected by proper fuses and switches, and a suitable distribution panel should be located at a convenient point giving full control of all circuits within the building. Frequent examination should be made of all contacts, fuses and switches to Insure minimum loss and to improve the operation of the lamps and apparatus connected to the system. In our next "Electrical Talk" we will discuss the three-wire service within a building. PART PROCEEDS WILL GO TO CHARITY. At a conference between the lessees of the Colonial Theatre, Indianapolis, Ind., and Supt. M. T. Hyland regarding the law pertaining to the running of photoplay performances on Sunday, resulted in a decision for the photoplay managers. It was claimed that, if part of the proceeds were given to charity, the theatre people were not violating the Sunday amusement law. There is a city ordinance prohibiting vaudeville performances on Sunday, but as this says nothing about photoplay shows, they will be permitted to run, providing that part of the proceeds go to charitable purposes. The managers are not only willing to do this, but will help any worthy charitable institution that is struggling for existence,