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Page Title:
Electrical Controls Random Endurance Test. |
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|  MIL-S-85419 (AS)
shall be vibrated at the displacements and accelerations defined
by Figure 10 with the frequency continuously varying at a
logarithmic rate from 5 to 1000 Hz and back to 5 Hz in
approximately 20 minutes at double amplitudes or vibratory
acceleration levels of Figure 10. This shall be repeated for a
total of five cycles on each axis.
4.5.6.3 Electrical Controls Random Endurance Test.
If the
electrical controls for the starter/APU are separately mounted
they shall be mounted on text fixture the same as it would be in
the service installation mounting. The electrical controls shall
be continuously excited for three hours along each of three
mutually perpendicular axes in accordance with Figure 11. During
these tests, the instantaneous random vibration peaks may be
limited to 3 times the rms acceleration level. The rms
acceleration level shall not be less than the specific minimum
value. Resonant modes of the moving mass (vibration exciter
moving element, fixture and the test item) shall be equalized or
compensated for within the frequency range of the test curve.
The applied vibration spectrum shall normally be within the
tolerance of 1.5 db between the frequencies of 10 to 1000 Hz.
A wave analyzer shall be used to assure the specified
equalization tolerances. The wave analyzer shall have a maximum
bandwidth of 25 Hz below 1000 Hz, with a sweep rate (Hz/second)
not exceeding .034 times the filter bandwidth squared, The
integration time constant shall not be less than one second.
4.5.7 Start Cycle Abort. A minimum of two start cycle aborts
shall be conducted at output shaft speeds of 500, 1000, and 2500
rpm by interrupting the electrical start control signal. One
abort shall be completed after each 50 endurance start cycles.
4.5.8 Running Engagement. The starter/APU shall be operated to
cutout speed after which it will be subjected to engagements
during coast down at speeds ranging from zero to cutout speed in
equal increments selected to provide a minimum of ten
engagements. No damage to the starter/APU shall result from this
test.
4.5.9 Teardown Inspection. A teardown inspection consisting of
complete disassembly of the starter/APU shall be made at the
completion of the qualification test. Dimensional inspection
shall be made of all wearing parts. Rotating parts shall be
subjected to Magnaflux of Zyglo inspection, except that assembled
anti-friction bearings shall not be subjected to Magnaflux
inspection. Rotating parts subjected to centrifugal stresses
shall be measured on dimensions likely to show growth. Where
practicable, seal clearances shall be determined. Failure of or
any abnormal wear or damage to any part, sufficient to impair
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