MIL-DTL-49055F
4.6.7 Thermal shock. Cable specimens 38 to 40 inches (965 to 1020 mm) long shall be subjected to
five continuous cycles at the high and low temperatures specified (see 3.1). The specimens shall be
maintained at each temperature extreme for a minimum of 30 minutes. A maximum dwell time of two
minutes shall be allowed for transfer between test chambers. After completion of the fifth cycle, the
specimens shall be removed from the test chambers, and allowed to stabilize at room temperature. The
specimen shall be examined for evidence of cracking, or shrinkage of the insulation.
4.6.8 Conductor continuity. All cables shall be tested for conductor continuity with an ohmmeter or
other suitable testing device.
4.6.9 Flammability. Cables shall be tested for flammability in accordance with the VW-1 flame test of
UL 1581. During calibration of the gas flame, the blue inner cone of the flame is to be approximately 1.5
inches high (38 mm) and the temperature at its tip is to be 836 °C (1537 °F) or higher which shall be
verified with an accurate measuring device. The cables shall not burn for more than the specified time
nor release flaming particles, and the flame shall not travel more than the distance specified in VW-1.
4.6.10 Folding. A specimen of cable 26±.062 inches (914±1.6 mm) shall be folded 180° transversely
and pressed between two pieces of smooth-surfaced flat metal twice the width of the cable, with a
pressure of 30±1 pounds of force per inch of cable width of the test specimen (see figure 2). After 15±1
minutes under pressure, the specimen shall be unfolded and the pressure reapplied to the unfolded
creased portion of the cable for an additional 15±1 minutes. Unless otherwise specified (see 3.1), the test
shall be conducted at 23±5 °C. This procedure constitutes one complete cycle. After two complete
cycles of folding and unfolding on the same creased portion, the cable shall be checked for continuity and
shall be examined for evidence of cracking, fracturing, or rupturing. The cable shall then be subjected to
the dielectric withstanding voltage test as specified in 4.6.4.
FIGURE 2. Transverse fold (180º).
14
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business