Journal of the Society of Motion Picture and Television Engineers (1950-1954)

Record Details:

Title:
Journal of the Society of Motion Picture and Television Engineers
Date:
1950-1954
Publisher:
Easton, Pa. : The Society
Volume:
Journal of the Society of Motion Picture and Television Engineers
Leaf #:
000512
Language:
English
Collection:
Technical Journals
Format:
Periodicals
Contributor:
Prelinger Library
Sponsor:
MSN
Coordinator:
Media History Digital Library
Date Added:
July 19, 2022
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START j. 1. Micro-shadowgraph of head wear 250,000 FT. 120 MRS 580,000 FT -268 MRS. 750,000 FT -345 MRS. 1,000,000 FT. -475 HRS 1,420,000 FT -660 HRS. 1,680,000 FT. -777 HRS. -. u iJ E 005 Ns^rl J8 HOUR s — •*. -— -^ -^ — ^, 580 HOURS 1 ? .010 "^ ^. •^••^^ ±= 3 5 .015 Ll 020 L. J J L " ^> \ 7 777 HOURS' 7 400,000 800,000 1,200,000 1,600,000 < FEET OF' FILM i 1 ^ ** "*"" "* "*» O\ x \ / s^ — ORIGINAL THICKNESS OF POLE PIECE =.025 IN 7ed every four hours, and the contour of te head was checked on a Jones & imson comparator at 100:1 magnifi •ition, every eight hours (Fig. 1). tiese loops had 6000 cycles/sec pre Icorded on them to check the output jdtage of the head throughout the tests. In the 4-hr period, one loop passed 60 times through the projector and ere was no noticeable drop in the out Fig. 2. Effect of wear on pole-piece thickness. put voltage of the 6000-cycle signal. The heads tested were used to record and reproduce signals after the tests were terminated and they still functioned satisfactorily. Figure 2 shows the rapid wear of heads during the first 88 hr in test. This is due to the small pole-piece area of a new head supporting the film and to its surface condition. The remainder of del Valle and Ferber: Wear of Magnetic Heads 503