MIL-DTL-151F
4.4.9 Audible noise. The audible noise shall be noted to determine compliance with 3.11. Tests with noise
instruments are not required unless specifically required by the contract or order.
4.4.10
Insulation resistance. The insulation resistance of the complete fan shall be measured at the conclusion
of the 4 hour operation test (see 4.4.8) to determine compliance with 3.16.2.
4.4.11
Low temperature starting. Starting tests after the fan has been at a temperature of minus 18º C (0º F)
or lower for at least 24 hours shall be conducted to determine compliance with 3.7. Similar tests shall be conducted
after the fan has been at a temperature of 38º C (100º F) for 4 hours.
4.4.12
Life tests. The fans selected for test shall be subjected to a 14 cycle life test; each cycle to consist of
360 hours running at room temperature and at rated voltage and frequency, then 24 hours idle at a temperature of
minus 18º C (0º F), followed by 8 hours running at minus 18º C (0º F) and rated voltage and frequency. At the end of
each 8-hour run, power input and speed shall be measured, while the fans are still subjected to a temperature of minus
18º C (0º F). The power input and speed shall be measured to determine conformance with this specification.
4.4.12.1
Dielectric. Upon completion of the life test, the fans shall be subjected to an a.c. potential of 900 volts
for 1 minute, applied between the current-carrying parts and the frame.
Wear. Upon completion of the dielectric test (see 4.4.12.1), the fans shall be dismantled and examined
4.4.12.2
for wear and defects to determine compliance with 3.14.
4.4.13
Shock. The fans shall be subjected to class III shock in accordance with the method specified in
MIL-S-901. The features of test shall be as follows:
(a)
Type type A.
(b)
Weight light.
(c)
Principal functions circulating air.
(d)
Cause for rejection:
(1) Breakage of any part of the fan tested, or cracks indicating incipient breakage.
(2) Deformation of parts that will cause an increase in vibration, an increase of noise, or cause
active interference between parts.
(3) Changing of position of the fan after it has been secured in set position.
(e) Mounting. The fan shall be mounted by means of mounting fixture 4A as shown on figure 5 of
MIL-S-901.
4.4.14
Permeability (class 2 fans only). The permeability of nonmagnetic material shall be determined by
the use of permeability indicators conforming to ASTM A342/A342M.
4.4.15
Vibration. Vibration tests shall be conducted in accordance with type I (environmental vibration)
requirements of MIL-STD-167-1.
4.4.15.1
Test feature. The test feature for shock test (see 4.4.13) shall also apply to vibration tests. The
unit of equipment selected for vibration tests shall be the same unit as selected for class HI shock tests.
5.
PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or order
(see 6.2). When actual packaging of material is to be performed by DoD personnel, these personnel need to contact
the responsible packaging activity to ascertain requisite packaging requirements. Packaging requirements are
maintained by the Inventory Control Point's packaging activity within the Military Department or Defense Agency, or
within the Military Department's System Command. 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.
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