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Page Title:
Table 3. Life test sample selection |
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|  MIL-D-85859(AS)
specified in 4.6.1. The life test sample shall be selected by the
Government inspector in accordance with table III. (Distribution boxes
which have successfully passed the Sampling Tests, Reliability Tests, or
Special Tests may be selected for life tests.) When reliability tests are
conducted, the life test may be omitted if, during the reliability tests, a
quantity of distribution boxes equal to, or more than, that listed in table
III receive at least 300 hours each of test time.
TABLE III.
Life test sample selection
Quantity to be Selected
Quantity of Distribution
for Sampling Test
Boxes Offered for Acceptance
1
First 25
1
Next 175
1
Next 300
1 for each additional
500 or fraction thereof
4.6.1 Test conditions. The life test shall be conducted under the standard
conditions specified in 3.4.4.
4.6.2 Test periods. The test may be run continuously or intermittently.
Any period of operation shall be of sufficient duration to permit the
distribution box temperature to stabilize. Periodically, the distribution
box shall be turned on and off several times and put through its various
phases of operation
4.6.3 Performance check. At approximately 8-hour intervals during the
test, a limited performance check shall be made.
In the event of part failures, the defective part shall
4.6.4 Test data.
be replaced and the operation resumed for the balance of the test period.
In the event of a failure, the Government
4.6.4.1 Failure report.
inspector shall be notified immediately.
4.7 Environmental tests. The distribution box shall be subjected to
environmental tests specified in 4.7.1 through 4.7.8.
4.7.1 High temperature. The distribution box shall be tested in accordance
with MIL-STD-810, Method 501.2, Procedure I modified as follows
Step 1. Perform operation tests of 4.5.1.2 under the c losely
a.
controlled conditions of MIL-STD-810.
b.
Step 2. The high storage temperature shall be 85C. The storage
temperature shall be maintained for 24 hours. The storage temperature
shall be 85 for 4 hours and 75C for the following 20 hours.
Step 4. The highest continuous operating temperature shall be 55C.
c.
The distribution box shall be operated for 20-minutes intermittently
at 71C after the required warm-up time. The relative humidity
shall be between 20 and 35 percent.
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