MIL-DTL-9398D
CAUTION: Provide adequate ventilation during the following test.
4.5.17 Endurance. The generator shaft rotational backlash shall be measured and shall meet
the requirements of 3.4.4.3. The generator shall then be mounted on the engine accessory drive of
figure 1. The drive shall have its centerline displaced 0.007 inch from centerline of the pilot and the
generator mounting pad face shall be canted 0.008 inch TIR out of square with the centerline. The
generator shall then be connected to three 20-ohm 100-watt Y-connected resistances. Two generators
shall be operated on this drive, with this load, and with the generator supplied with oil in accordance
with MIL-PRF-7808 as specified in 4.5.6 for 1,000 hours in the independent continuous simultaneous
cycles shown in table I.
TABLE I. Endurance test cycles.
Speed
Temperature
Time
350 RPM ± 50 RPM for one minute
350 ºF ± 9 ºF (177 °C ± 5 °C)
24 ± 8 hours
Ambient room temperature
4 ± 2 hours
then
-67 ºF ± 9 ºF (-55 ºC ± 5 ºC)
24 ± 8 hours
Ambient room temperature
4 ± 2 hours
4,200 RPM ± 50 RPM for four minutes
4.5.17.1 Oil leakage control group test. Two other generators shall be operated in the
same manner except they shall not be supplied with oil as specified in 4.5.6.
4.5.17.2 Milestone checkpoints. At the conclusion of each 100 hours, each generator shall be
subjected to and meet the requirements of 3.4.4.3 and 4.5.5. At the conclusion of 1,000 hours, each
generator shall be subjected to and meet the requirements of 4.5.6 except that 5 cc leakage shall be
allowed. No screw or other part shall become loosened or damaged as a result of this test.
4.5.18 Humidity. The generator shall be mounted with the shaft in a horizontal position and
tested as specified in MIL-STD-810, test method 507.4. The external connections shall be made to
the generator in such a manner as to simulate installed conditions. The generator shall be subjected
to and meet the requirements of 4.5.2 within one hour after the generator is removed from the
humidity chamber. The generator shall then be subjected to and meet the requirements of 4.5.3 and
4.5.5.
4.5.19 Fungus resistance. The generator with external connections, to simulate installed
conditions, shall be subjected to a fungus test in accordance with MIL-STD-810, test method 508.5,
except the test period will be 14 days. At the option of the procuring activity, fungus tests on
components parts of the generator may be accepted in lieu of or in addition to tests on the assembled
generator.
4.5.20 Salt spray. The generator shall be subjected to a salt fog test in accordance with
MIL-STD-810, test method 509.4 except spray will be for a continuous period of 50 hours. The
external connections shall be made to the generator in such a manner as to simulate installed
conditions. At the end of the 50-hour period, the generator shall be subjected to and meet the
requirements of 4.5.1 and 4.5.2. The generator shall also be subjected to 4.5.6 but the allowed
leakage shall be 5 cc for the 1-hour period.
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