bh A 
AE 
(6) 
(7) 
(8) 
(9) 
(10) 
(11) 
(12) 
(13) 
REPORT OF COMMISSION V 
would be 0, 10,000, 20,000, 30,000 operations and so on, until 
locking up or failure occurred. In the case of d-c relays, the 
polarity should be noted. The magnification of the contact 
points should also be calculated for accurate determination of 
deformation. 
Contact spring performance) The contact and reset spring and 
Reset spring performance (stud performance are very closely 
Stud performance [interlinked. The performance of 
springs on original design is notoriously poor. The formulae for 
the design of springs are approximations only. Until compara- 
tively recently, the performance of the spring was judged by 
life tests. This did not show why the spring failed; but when the 
spring failed, the guess work began. And there were no apparent 
short cuts. Then the high speed motion picture camera was used 
to slow down the action and, consequently, phenomena, such as 
standing waves, flexibility, points of stress and strain, and snub- 
bing action, could be observed, both qualitatively on projection, 
and quantitatively with frame by frame analysis. When the 
snubbing action of the stud could be observed it was found that 
a small fraction of an inch change in position would often break 
up the standing waves, which cause contact chatter. The whole 
gamut of springs, such as flat, helical, coil, et cetera, were natural 
subjects for similar analysis. The engineering time saved cannot 
be calculated. One spring analysis with a high speed camera 
would more than pay for the cost of the high speed laboratory. 
Effect of temperatures and pressure on performance. These 
effects overlap the other reaction studies of operate time, spring 
behavior, et cetera. For certain analysis it might be necessary to 
use a camera in the cold or hot test chamber; therefore, the 
camera must be designed to work under these conditions. There 
has always been a question as to how arcs behave under reduced 
pressure, such as is encountered at high altitudes. Obviously, 
any method of study will lead to many interesting conclusions. 
A particular study, at present, might be the difference in 400 
cycle and d-c arcs at altitude conditions up to 100,000 feet of 
more. 
Effect of acceleration and deceleration | The effects of shock, vi- 
Effect of shock tbration and “g’ tests 
Effect of vibration jare important. If any of 
these phenomena cause unwanted closure or opening of con- 
tacts, serious malfunctioning of the associated equipment may 
occur. The majority of these tests would be qualitative. The ad- 
vantage of the high speed camera is that it is capable of picking 
up erratic or aperiodic actions; while irregular malfunctioning 
usually cannot be seen with a stroboscope. 
Effect of corrosion. The effect of corrosion can best be studied 
with a time lapse motion picture camera. This would cover 
moisture, salt spray and chemical vapor effects, as well as at- 
mospheric oxidation. For example, if a corrosion test was going 
to last 200 days, and for a sequence of 600 pictures (25 seconds 
projection time), one picture would be taken every 8 hours. The 
lighting would have to remain the same for each picture. It is 
true that fading of the latent image might affect the produced 
picture; but the film manufacturer would probably be able to 
give approximate figures on the effect of fading with original 
exposures on request. 
GV-73 
The action of the relay was selected as a typical study in both qualitative 
and quantitative analysis. Similar analyses can be made of anything that moves.