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Post retention and thread breaking strength |
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|  MIL-P-48189D(AR)
4.5.7.4 Breakwire function of sensor assembly. After the
sensor assembly is tested in accordance with 4.5.7.1, 4.5.7.2,
4.5.7.3 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
exceeds the limit specified in 4.5.7.2. Any sensor assembly which
does not meet the requirements specified in 3.4.4 shall be classed
defective.
This test is destructive. Those units that are capable
of meeting the requirements of the test specified in 4.5.7.5 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.
4.5.7.5 Post retention and thread breaking strength. After the
sensor assembly is tested in accordance with 4.5.1.1, 4.5.7.2,
4.5.7.3, and 4.5.7.4, and with the unit remaining in-the test-
fixture, the specified force shall be applied at a rate of 4
inches/see 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 tested shall not be returned to the lot. The
rate of pull shall be a person walking at a normal rate.
4.5.7.6 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 . The soldered connection shall have a smooth, bright
appearance with metallic luster and shall not have a chalky, gritty
surface, nor exhibit point (peaks), pits, scars, and fractures. The
connections shall be completely covered by solder to the extent that
no base metal is visible, with the exception that exposed copper is
permissible on the end of the cut wires.
4.5.7.7 Molding material intrusion test. The sensor assembly
will be placed Into a test brick mold with (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 3.4.6 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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