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Breakwire function of sensor assembly. |
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|  MIL-M-70779 (AR)
4.5.4.3 Breakwire function of sensor assembly. After the
sensor assembly is tested in accordance with 4.5.4.1, 4.5.4.2 and
with the unit remaining in the test fixture, a suitable force gage
shall be attached to the tripline at a point just above the
barrier. A pull force shall be applied along the axis of the
bobbin post and the breaking force shall be noted. The breaking
force is that force at which the resistance across the exposed
ends meets the requirements specified in 3.4.3. Any unit that
fails the pull force test, as specified in this paragraph, shall
be classified defective. This test is destructive. Those units
that are capable of meeting the requirements of the test specified
in 4.5.4.4 shall be used for that test even if they failed to meet
the requirements of this test. The rate of pull shall be a person
walking at a normal rate.
4.5.4.4 Post retention and thread breaking strength. After
the sensor assembly is tested in accordance with 4.5.4.1, 4.5.4.2,
4.5.4.3 and with the unit remaining in the test fixture, the
specified force shall be applied at rate of 4 inches/second
minimum to the tripline along the axis of the bobbin post. Any
unit that releases the bobbin post or on which the tripline breaks
shall be classed defective. This test is destructive. Units so
tssted shall not be returned to the lot. The rate of pull shall
be a person walking at a normal rate.
4.5.4.5 Soldered electrical connections of sensor assembly.
The electrical connections of the breakwire to the breakwire
terminals shall be tested for electrical continuity using a
suitable ohmmeter, and shall be tested for mechanical bond
strength using a suitable force gage. The force shall be applied
at the center of the breakwire through a hook or similar fixture
that does not damage the wire at the point of application. The
force shall be applied perpendicular to the breakwire terminal and
in the direction that will lift the breakwire from the terminal.
Any assembly which fails the electrical continuity test or the
mechanical bond strength test shall be classed defective.
Assemblies
The mechanical bond strength test is destructive.
so tested shall not be returned to the lot.
4.5.4.6 Molding material intrusion test. The sensor assembly
will be placed into a test brick mold with twelve (12) sensors per
mold. Shrink tubing will be assembled to the sensor nozzles and
exit the mold. Sensor plugs will be assembled to the cap end.
The mold will be closed and subjected to the normal wedge molding
process. The test brick cure will be for a minimum of 16 hours at
155 + 10F cure temperature. The sensor caps shall be
removed and the test brick assembled to an approved test fixture.
The pressure specified in 3.4.5 shall be applied to the protruding
end of the shrink tubing. This is a destructive test. Units may
not be returned to the lot.
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