Kinematograph year book (1944)

Film Exhibition and Kinema Technique. 213 4. This is a non-automatic method in which the safety lights are connected to an independent battery fitted with small pilot lamps connected up to the main lighting switch, which are always on when the main switch is closed, but are actually fed by the battery. The trickle charger is set, and to avoid any possibility of the trickle charge " apparatus failing to function, and such a failure escaping notice, so as to allow the cells to run down, a battery voltage indicator is provided. The widespread use of the other D.P. speciality, the Kathanode sound battery, indicates exhibitor and technical appreciation of its dependability and long life. Research is continually taking place, but there is unlikely to be any immediate change in their construction. Chloride Electrical Storage Co., Ltd. — The Home Office now permits the use of approved automatic change-over switches in connection with the safety lighting of kinemas, subject to certain conditions, details of which have been issued to all licensing authorities. The " Keepalite " emergency lighting system, incorporating an automatic change-over switch to the required specification is therefore suitable for use in kinemas. Other important advantages of the " Keepalite" are that it requires a minimum of attention, its high efficiency com lined with economy and long battery life. The wartime modification of the *' Keepalite " system may now be adopted by any exhibitor, who has only to notify his Local Authority, bringing the new conditions to its notice. These are : — (1) The switch shall be an automatic quick-acting change-over switch, conforming to the appropriate British Standard Specification current at the time when the switch is brought into use, and shall connect the safety lighting to a battery of accumulators ; (2) The rated capacity of the switch shall not be less than 50 per cent, in excess of the maximum current demanded by the safety lighting system ; (3) The capacity of the battery shall be sufficient to supply at normal voltage the load for not less than three hours ; (4) The battery shall be fully charged before the first admission of the public ; (5) The rate of charging the battery shall be so regulated and adjusted that the battery does not discharge under normal conditions ; (6) Any converting or rectifying apparatus for the charging supply to the battery shall be reserved for that purpose only ; (7) Where the charging arrangements permit a reversal of current, controlling switchgear shall be provided capable of automatically disconnecting the battery from the source of supply, should the latter fail ; (8) The controlling switchgear associated with the safety lighting battery shall be tested by a competent person each day before the public is admitted to the premises, and the results recorded. The test shall include disconnection of the source of supply and observation of the consequential automatic operation necessary to give a supply to the safety lighting system ; (9) In the event of failure of the source of supply whence the battery is charged, the public shall be required to leave the premises before the charge remaining in the battery is reduced below that necessary to supply the whole of the safety lighting for a further period of one hour ; (10) A . . . suitable visual or audible signal shall be arranged to indicate a failure of the source whence the battery is charged. Electric Construction Co., Ltd. — -The high efficiency of the emergency lighting rectifier equipment manufactured by the Electric Construction Co., Ltd., is recognised throughout the industry. A typical equipment of this nature which is in demand is a rectifier having an output of 100 to 140 or 200 to 280 volts, grid control, giving infinitely smooth current regulation from 0 to 40 amps. It is a completely self-contained unit, including control panel and fuse-board. British Thomson-Houston Co., Ltd.— The B.T -H. " Thyrect " equipment for emergency lighting in kinemas automatically maintains the battery and safety lights under all conditions, The equipment has unique advantages, one of the most important being that it gives " trickle " charge at constant