Motion picture projection; an elementary text-book (1921)

Record Details:

Title:
Motion picture projection; an elementary text-book
Date:
1921
Publisher:
New York, Theatre Supply Co.
Volume:
Motion picture projection; an elementary text-book
Leaf #:
00062
Language:
English
Collection:
Books
Format:
Books
Contributor:
University of California Libraries
Sponsor:
MSN
Coordinator:
Media History Digital Library
Description:
Date Added:
July 19, 2022
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MOTION PICTURE PROJECTION 61 the machine switch is pulled, it stops a no-load current from passing through the primary coil of the transformer. POINTS TO REMEMBER ABOUT TRANSFORMERS Make sure that the primary coil (marked line) is connected to the source of supply. See that transformer is connected between machine switch and arc lamp. Do not use any resistance device in series with a transformer. Make sure that all the connections are tight. Cover all line terminals on transformer with tape. Place transformer away from metal walls of booth. Keep arc short. See that voltage and cycles marked on transformer corresponds with supply voltage and cycles. THE HALLBERG ECONOMIZER The Hallberg economizer is simply a transformer of the semi-constant current type, taking A. C. current at line voltage and delivering A. C. current at arc voltage. Semi-constant means that it will take the line current at a fixed potential and will deliver from the secondary a steady amperage flow regardless of the length of the arc. The economizer consists of a continuous rectangular core, on one leg of which is the primary winding, on the opposite core leg is the secondary which is made of larger cross section wire, this coil is connected to lamp.