 |
|||
|
|
|||
| ||||||||||
|
|  MIL-C-82629(OS)
4.5.4.2 Low temperature (90-degree bend test)
(a) While the cable is mounted in a suitable fixture, a 90-degree bend test shall be performed
at -40 3 degrees F (-402 C). The cable assembly and test fixture shall be conditioned at the
test temperature for at least 12 hours prior to initiation of the test.
(b) The cable assembly shall be mounted and clamped at two points on the test fixture such that
a 90-degree bend with a radius not to exceed 6 inches (152mm) shall be formed within a 12-inch
(305-mm) length of cable (see Figure 4). The cable shall be rigidly secured to the underside of a
fixed support lying in a horizontal plane at one clamp position, and rigidly secured to a pivoting
arm which shall be so mounted as to oscillate from a vertical position to a horizontal position.
When in its horizontal position, its axis shall form and extension of the plane of the fixed support,
and the cable shall be attached to the underside of the arm. The attachment of the cable to the
oscillating arm shall be made when the arm is in the vertical position. The pivot axis of the os-
cillating arm shall intersect the longitudinal axis of the fixed support and shall be equidistant
from the two clamping points. The fixture will be so designed that the section of cable between the
clamp positions shall not touch any portion of the mechanism or cold box during the test.
(c) One cycle of test shall consist of an oscillation of the pivot arm from the vertical position
to the horizontal and back to the vertical. The test shall be conducted at a rate of one cycle per
minute, with each half cycle to be accomplished within 6 seconds. The delay between cycles may
occur at the end of either half cycle or may be divided to occur at the end of each half cycle.
(d) Continuity of all conductors shall be monitored continuously. The test shall be stopped and
the number of cycles recorded. in the event of failure of any conductor. The test shall consist of
500 cycles of bending.
4.5.5 Electrical tests
4.5.5.1 Dielectric strength. The cable assembly shall be tested dry, without immersion in water,
in accordance with Federal Test Method Standard No. 228 (Method 6111) to determine conformance with
3.8,1.
4.5.5.2 Insulation resistance. The cable assembly shall be tested dry, without Immersion in
water, in accordance with Federal Test Method Standard No. 228 (Method 6031) to determine conformance
with 3.8.2.
4.5.5.3 Continuity.
Each circuit of the cable shall be probed with a 6-12 vdc buzzer, or equiva-
lent, for continuity.
4.5.5.4 Contact, conductor resistance. The cable assembly shall be mated to a Torpedo Tube Con-
nector Mk 42 Mod 1 and the resistance measurement made from each female socket of the connector to
the corresponding male pin in the in-line connector (see Figure 5). The ohmmeter or Kelvin bridge
shall be capable of measuring a resistance of less than 0.1 ohm with an accuracy of at least 0.02
ohm. The resistance of each circuit shall be determined.
4.5.6 Environmental tests
4.5.6.1 Vibration. The vibration test shall be performed with the cable in the mated condition.
The mated cable assembly and torpedo tube cable connector shall be mounted to a suitable vibration
fixture and this fixture in turn shall be mounted to a sinusoidal vibration system as illustrated in
Figure 6. The vibration fixture shall be sufficiently rigid to prevent resonant frequencies greater
than 1.5 to 1. All circuits of the mating connectors shall be wired in series. The input control
accelerometer shall be placed on the vibration fixture adjacent to the cable tube door mounting
point. Two monitoring accelerometers shall be mounted to the cable assembly, one on the in-line
connector end and one on the tube door end.
4.5.6.1.1 Vibration schedule and levels. Vibration shall be conducted in three mutually perpen-
dicular directions (see Figure 6) in accordance with the following schedule. All tests. in one
direction shall be completed before proceeding to tests in another direction.
(a) Resonance search. The sample shall be vibrated at frequencies from not higher than 10 Hz to
not less than 33 Hz at a table vibratory amplitude of 0.010 0.002 inch (0.250.05mm) and from not
10
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals