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

Page scan 00061 from Motion picture projection; an elementary text-book

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 #:
00061
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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60 MOTION PICTURE PROJECTION sure of 500 volts or 500X20=10,000 Watts or 10 K. W. On the secondary we have 200 amperes at a pressure of 50 volts or 200X50=10,000 Watts or 10 K. W. So we see that the wattage on the primary is equal to the wattage on the secondary, assuming that there is no loss in transformation. We know that there are two forms of losses in all transformers, the iron or core loss and the copper or coil loss. These losses total about 10 per cent. The core losses are going on as long as the switch on line side of the transformer is closed ; in other words Powers Inductor Connected to Two Arc Lamps while the transformer is carrying a no-load current. The copper losses only take place while the arc is burning or current is being drawn from the secondary coil. Let us suppose the primary coil is drawing 20 amperes at a pressure of 100 volts, the wattage in the primary circuit would be 100X20=2,000 Watts. Let us assume that the losses in transformation is 10 per cent, this would mean that the wattage on the secondary circuit would be 2,000 Watts less 10 per cent or 1,800 Watts. Transformers should always be connected between the machine switch and the arc lamp, so that when