MIL-PRF-17773C(SH)
4.6.26 Vibration. Switches shall be subjected to Type I vibration tests in accordance with MIL-STD-167-1.
The tests shall be conducted with the switch in each operating position with the switch carrying rated current at rated
frequency. Control circuits shall be energized as in actual service. An oscillograph or other suitable instrument
shall be used to check correct power transfer and operation of any auxiliary contacts. Fuses (or other indicators
which provide a positive indication) shall be connected in a manner to detect any momentary shorting between live
parts or live parts and ground.
4.6.26.1 Conditions. Switches shall retain structural integrity when the vibration exists along each of the three
rectilinear orientation axis of the switch as installed on shipboard (i.e., vertical, athwartship, and fore and aft).
Switches shall be tested in the same mounting configuration as the one chosen for shipboard installation (if shock or
isolation mounts are utilized, these shall not cause resonance), and shall be subjected to:
a. An exploratory vibration sweep from 4 Hz to 33 Hz at 0.010-inch peak amplitude with the sweep in 1-Hz
increments and held at each discrete frequency for a minimum of 15 seconds,
b. A variable frequency test with the following amplitude and frequency profile: 5-minute dwell at 1-Hz
increments from 4 Hz to 15 Hz at 0.030-inch peak amplitude; 5-minute dwell at 1-Hz increments from 16 to 25 Hz
at 0.020-inch peak amplitude; 5-minute dwell at 1-Hz increments from 26 to 33 Hz at 0.010-inch peak amplitude,
and
c. A 2-hour endurance test at the highest frequency resonance (resonance defined as any frequency where the
transmissibility is 2 to 1 or greater) and applicable 5-minute dwell amplitudes found during the exploratory sweep.
If no resonance can be found, the 2-hour endurance test shall be run at 33 Hz.
4.6.26.2 Indications of failure. A switch shall fail the test if it cannot perform its intended operating functions
during and after such tests, or if one or more of the following occurs during the tests:
a.
Contact between live parts and the enclosure.
b.
Enclosure door opens.
c.
Structural parts are damaged or loosened.
d.
Functional parts are damaged or loosened.
e.
Inadvertent transfer of load.
f.
Re-transfer operation is initiated.
g.
Closed auxiliary contacts momentarily open or open auxiliary contacts momentarily close.
h.
Main line contacts exhibit contact chatter.
i. The switches shall be thoroughly examined after the tests to determine whether there is evidence of items c
and d above. The switches shall be subjected to and pass the dielectric withstanding voltage test (see 4.6.18) after
the vibration tests.
4.6.27 Airborne noise. When specified (see 6.2), the switch shall be tested for airborne noise in accordance
with MIL-STD-1474.
4.6.28 Structureborne noise. When specified (see 6.2), the switch shall be tested for structureborne noise in
accordance with MIL-STD-740-2.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or
order (see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor personnel, these
personnel need to contact the responsible packaging activity to ascertain packaging requirements. Packaging
requirements are maintained by the Inventory Control Point's packaging activities within the Military Service or
Defense Agency, or within the military service's system commands. Packaging data retrieval is available from the
managing Military Department's or Defense Agency's automated packaging files, CD-ROM products, or by
contacting the responsible packaging activity.
25
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business