MIL-DTL-5898H
4.6.4 Jacket tensile strength, elongation, and set.
4.6.4.1 Unaged. An unaged jacket shall be tested for tensile strength using method 3021 of
FED-STD-228 and for elongation using method 3031 of FED-STD-228. Set, when required, shall be
tested using method 3161 of FED-STD-228.
4.6.4.2 Air-aged. A sample of the jacket shall be air-aged for 166 hours at 70 °C and then tested for
tensile strength and elongation using the methods listed in 4.6.4.1.
4.6.4.3 Oil immersion. The jacket shall be subjected to the oil immersion test in accordance with
method 4223 of FED-STD-228.
4.6.5 Flammability. Insulation flammability testing shall be performed in accordance with the VW-1
flame test method of UL 1581.
4.6.6 Electrical tests.
4.6.6.1 Conductor resistance. The resistance of each conductor of the cord shall be measured in a
bridge circuit. The arithmetical average of the measured values shall be used to calculate the conductor
resistance.
4.6.6.2 Dielectric strength. An alternating potential as specified in 3.12.1 shall be applied between
two terminals, one being each conductor in turn and the other terminal being all the remaining conductors
tied together. The voltage source shall have a capacity of not less than 3 kilovolt ampere.
4.6.6.3 Insulation resistance. Immediately after successfully passing the dielectric strength test, the
insulation resistance shall be measured using a galvanometer with shunts and a dc voltage source of not
less than 125 V dc. The connections shall be as specified in 4.6.6.2. The test may be terminated when
the galvanometer indicates a steady insulation resistance value has been obtained. The measured
insulation resistance values shall be corrected to 15.6 °C if measurements are made at temperature other
than 15.6 °C.
4.6.7 Flexing test. Sample lengths of cord shall be selected from each 100,000 feet or one month's
production, whichever is less, and subjected to the following:
4.6.7.1 Preparation. Five specimens, each approximately 1.5 feet long, shall be clamped and
suspended through holes in a rectangular .500x.625 inch (12.7mm x 15.9mm) metal bar. The diameter of
the .625-inch (15.9mm) through holes shall be .005 inch (.13mm) to .010 inch (.254mm) greater than the
diameter of the cord undergoing the test. The through holes shall incorporate a .125-inch (3.17mm)
radius at the end from which the cords emerge (bending point). The cords shall be clamped in such a
manner that they will not turn in the holes during flexing. The clamping points shall be immediately above
the metal bar and cord clamps shall rest on top of the metal bar. A knot shall be tied near the free end of
each cord and a 3-pound weight shall be suspended from each knot, except for type WD-34/U, which
shall have a 1-pound weight suspended from each knot. The metal bar, supported horizontally, shall be
positioned in a test jig that will enable oscillation about its longitudinal axis through an angle or 120°
(60°each side of vertical).
4.6.7.2 Cord flexing life. The conductors of each specimen shall be connected in series with a 6-volt
lamp and a suitable power supply to indicate electrical continuity. The metal bar shall then be oscillated
at approximately 85 cycles per minute until electrical discontinuity occurs. The cord flexing life shall be
calculated by summing the total number of flexing cycles for each specimen and dividing by the total
number of specimens.
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