FED-STD-791D
9.14 Following a 16 hour cold-soak, the two torque tests shall be consecutively
performed using the LOWTEMP computer application program. The following
additional test conditions are applied to the torque test runs:
Test temperature: -54 ±0.5 °C
Test time: 5 minutes
Spindle speed: 1 rpm
Data scanning interval: 20 centiseconds
The torque reading starts when torque value is >0.1 N.m
9.15 Store the test results on a floppy disk and plot them on the formatted papers.
9.16 Cut off the cooling system, and remove the tested specimen assemblies from
the drive shafts and place them in the preheated oven until completely dried in order to
preclude rust formation.
9.17 For the second series of tests, the two remaining test specimen assemblies
shall be set up on the drive shafts identically to the previous tests.
9.18 Resume the cooling for the next four hours to restore the test temperature.
9.19 After four hours, two additional torque data shall be generated using the
above torque measurement procedure.
10. REPORT
10.1 Breakaway torque (N.m).
10.2 Running torque (N.m) at 5 minutes.
Note 2. Both determinations shall be calculated by the average of two test runs.
11. PRECISION
11.1 Repeatability
Breakaway torque: 10%
Running torque at 5 minutes: 7%
Note 3. Duplicate results by the same operator should be considered suspect if they differ
from the mean by more than the above amounts at the 95 percent confidence level.
11.2 Reproducibility has not been established.
Method prepared by
Army AT - 2006
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