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|  MIL-M-82433A(OS)
4.5.1.5 A humidity chamber capable of providing a constant humid-
ity condition of 95 percent at +110 degrees F for periods up to 8
hours.
4.5.1.6 Motor life testing equipment, including regulated power
supplies, switching circuitry, and loading fixtures, to operate the
motor through the duty cycle as specified in 3.3.3. The setup should
be adaptable to tests of both 4.5.2.4.2 and 4.5.2.7.
4.5.1.7 A vacuum and pressure chamber capable of operation from
2.7 to 20.0 psia with provision for traversing this range from the
lower to the higher limits at the rate of 0.5 psi per second.
4.5.1.8 Items of test equipment specified in 4.7.
4.5.2 Detailed preproduction tests
4.5.2.1 Vibration
4.5.2.1.1 Nonoperating. The packed motor (see 5.2) shall be placed
on a vibration platform that is fenced on all sides sc that the pack
cannot tip over or fall off the platform. With the packed motor in
the vertical position, gradually increase The frequency from 5 Hz
until the pack just begins to leave the platform. At this point,
the frequency shall be maintained and the tests will be continued for
1 hour.
4.5.2.1.2 Ready nonoperating and ready. The unpackaged motor,
mounted on a support frame, shall be rigidly attached to the vibra-
tion equipment. This support frame shall be capable of transmitting
the vibrations listed in Table I to the motor along the axes shown
in Figure 1. Vibration shall be conducted at three temperature condi-
tions: the motor stabilized at room temperature, at -45 50F and
at +140 5F. The resonant modes for each of the three temperature
conditions in each of the three axes shall be established by varying
the frequency of applied vibration slowly from 5 to 500 Hz in accord-
ance with Table I, for each temperature condition and in each axis.
If more than four resonances are encountered for any one temperature
condition on any one axis, the four most severe resonance points shall
be chosen for the tests at resonance, for that one axis and that one
temperature condition. The total vibration time in each axis shall
be 180 minutes, with the motor for 60 minutes of this time stabilized
at -45 5F, 60 minutes stabilized at +140 5F, and 60 minutes at
room temperature. The motor shall be vibrated for 10 minutes at each
resonance point for each of the specified temperatures in each axis;
the remainder of the 60 minutes shall be used in cycling per Table
V. The frequency rate during cycling shall be logarithmic such that
1/12 of the total vibration time is required to proceed from the lower
extremity of frequency range.
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