Exhibitors Herald World (Oct-Dec 1930)

November 22,1930 Exhibitors Herald-World 41 BETTER PROJECTION A Department Conducted for the Projectionist and the Exhibitor By F. H. RICHARDSON Lighting and Monitor Control Setups WHEN I was in Cranbrook, B. C, in the course of my trip this past summer, I visited the Star theatre and paid the projectionists there a number of compliments later on for the excellence of their work. Projectionists Ward and Burton at that time promised me a detailed description of certain things for publication, the receipt of which has been much delayed. I have been chasing around these United States of America the past few months so fast that Uncle Sam's postmen couldn't keep up with me. The following letter has just reached me: "Friend Richardson and Friend Daughter: We enclose herewith diagrams and some photographs of the various things shown you at the time of your visit in our city. "Figure 1, is a diagram of the emergency lighting automatic switching cir 5*-»T<H C«*NC*Tns 60 <\«\t Mflcv£sV r^ftide-T switch Rc<.*e* -$ sphino, ■ • He Fig. 1. -Diagram of the emergency lighting system auto matic switching circuit. cuit. We believe this diagram is largely self-explanatory and that it will serve as a guide in the application of this system in any theatre. "The magnetic switch we are using is made by the General Electric Company, but any make of magnetic switch of suitable capacity will do. The one we have is a three-pole switch, each pole being used to control a circuit. We thus are able to handle three circuits with one switch, and one 30-ampere switch of this type produces a total circuit capacity of 90 amperes, which should be ample for emergency lighting in almost any theatre. "The supply for this switch is brought through a point ahead of both the main fuses and the main switch, thus preventing any possible trouble to the circuit box should trouble develop in the house wiring, which may occur. Of course the entire installation should be very carefully made. The use of this circuit should not be permitted except under emergency circumstances, or when there is danger of panic. Under such conditions, the fewer fuses there are to give out, the more certain one can be of emergency operation. Except in emergencies, or for purposes of periodical test, the use of this circuit should, for obvious reasons, be absolutely forbidden. As we explained to you personally, we have one controlling station in the projection room, which is connected to the port shutter suspension bar, which therefore is the real automatic feature of the system. In addition to this station, we have a manually controlled station at the door man's posi To 1*1 I Auditorium of the Star theatre. tion. As many more can be installed as may be desired. Each manual station should be plainly labled, 'For Emergency Lighting Only.' "In operating, the toggle snap switch shown, which is held normally in position by a cord and ring attached to the port shutter bar, is pulled to closed position by the action of a suitable coil spring upon release of the port shutter bar. Current then flows to the magnetic coil of the magnetic switch, and because of the magnetic attraction of the coil, the switch plates are rocked to closed position, thus connecting the emergency circuit and holding them on until the snap switch is opened in the projection room. Manual operation from any of the other positions accomplish the same results, thus providing means for instant emergency lighting by any authorized person in the house staff from convenient positions in the auditorium. IN our own house, we have three of our regular house circuits connected to this system, and the feed from the magnetic switch is connected between the regular control switches and lights, care being taken to see that the polarity of these connections are the same as that supplied from the regular source. "Where there are entirely separate emergency circuits, this is a 100% fine way to operate them. It is more especially so if manual release of the port