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(+ 125 F) and after the internal temperature of the oil gear has reached equilibrium
1
at
temperature, the top surface shall be exposed to 360 BTU/Ft. Sq/Hr., for a
that
!
period of 4 hours. The oil gear then shall be tested for conformance with the perform-
ance requirements of this specification. The unit shall be allowed to return to normal
room temperature and test shall be made for conformance with 3.5.1.
-
4.4.3 Humidity - A test chamber that is capable of being sealed shall be used:
o
the source of heat shall be arranged in such a manner that the radiant heat will not
fall upon the unit being tested. An oilo gear shall be placed in the chamber, the temper- `
ature of which is adjusted to plus 46. 1 C + 1.1oC ( + 115F + 2F) and the relative
humidity adjusted to 95 percent* 5 percent. The unit shall remain under the above
conditions for a period of 6 hours. Theo temperature* of the chamber shall be readjusted
o
o
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to plus 26. 7 C + 1. 1 C ( + 80 F + 2 F) and the oil gear shall be allowed to remain under
this new condition for a period of 6 hours. The transitional period shall be 2 hours; `
the rate of change during that period shall be uniform. The above cycle shall be re-
peated 10 times. Immediately after this test, the oil gear shall meet the require-
ments of 3.5.2.
4.4.4. Rain. - The oil gear shall be mounted in the test chamber to simulate
installation conditions. The rain test chamber temperature shall be maintained be-
o
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tween 20 C to 30 C (68F to 86 F) throughout the test period. A simulated rainfall
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of 4 plus 1 inch per hour shall be produced by a suitable means of such design that
the water is emitted in the form of small droplets rather than a fine mist. The O
temperature of the water shall be maintained between llC to 24 C (51. 8F to 75.2 F).
o
The water spray shall be directed on the oil gear for a period of 2 hours in directions
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ranging from vertical to 45 from the vertical. The simulated rain shall be directed
on all surfaces of the oil gear that are normally subjected to rain when the instrument
is in its operating position.
4.4.5 Vibration. - The oil gear shall be mounted using its own mounting pro-
visions. to simulate field use. Each unit tested shall be vibrated successively along
each of the three mutually perpendicular directions with accelerations and excursions
as shown below. Applied frequency shall be changed at a uniform rate between the
limits indicated; the rate of change shall not exceed one cycle per second.
Time (each
Acceleration
Excursion
Frequency limits
direction)
-00000000
1 hour
0- 1 0 C p s
0.060 inch
00-09--00-
2 hours
1 0 - 20 Cps
0.030 inch
20-400 Cps
2 hours
2.5g's
oil gear shall be mounted, using its own mounting provisions,
4.4. $ Shock. - The
A shock of 20 g's shall be imparted three times in each di-
to
simulate field use.
rection along each of the three mutually perpendicular directions, making a total of .
q
18 shocks. Each shock impulse shall have a time duration of 11 + 1 milliseconds;
the maximum g value shall occur at approximately 5.5 miilliseconds and shall be
within * 10 percent. Filters used shall have cut-off frequencies selected to eliminate
all harmonics above the fundamental from the measured chock pulse.
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