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|  MIL-S-25980A(USAF) USAF)
4.6.10 Immersion.- The float switch shall be subjected to Immersion (leakage)
test Procedure I of MIL-E-5Z72. Leakage as defined in the test procedure shall[ con-
stitute fail-. At
end of the test period, the low specific gravity test shall
in acccordance with 4.6.3.1
be performed
I
4 . 6 . 1 1 Mechanical The float switch shall be subjected to equipment
operation shock teat Procedure V of MIL-E-5272. Maximum line voltage shall be
applied during test. At the end of this test, there shall be no evidence of fail-
ure or distortion, and the low specific gravity test shall be performed in accord-
ance with 4.6.3.1,
Exposion.- The float switch shall be subjected to explosion-
4.6.12
prood test Procedure III or IV, as applicable, of MIL-E-5272 The unit shall be
calibrated on completion of the teat in accordance with 4.6.3.1.
~ * - The float switch shall be subjected to salt spray test
4.6.13
Procedure I of MIL-E-5Z72. At the end of the test period, the salt deposit shall
be removed with warm water, the swicth dried, and the low specific gravity test
shall be performed In ` ccordance with 4.6.3.1. Any evidence of corrosion which
might q chwrmly q ffect the float switch shall be cause for rejection.
- The float switch shall be subjected to a radio
4
.
6
.
1
4
~
*
Interference test in accordance with MIL-STD-826.
4.6.15 De-icing.- Float switches with de-icing heaters shall be tested at
maximum line voltage and in an ambient temperature of 160 F. The maximum tempera-
ture of heated parts in contact with fuel or fuel vapors shall be measured and
shall not exceed 275 F. The heated parts shall be submerged in fuel conforming to
grade JP-4 of MU-J-5624, at
F for 100 hours while maintaining maximum line
voltage. At the end of the teat period, the low specific gravity test shall be
performed in accordance with 4.6.3.1.
~ * - The float switch shall be operated for a minimum of
4.4.16
100,000 complete cycles. The maximum rated resistive load shall be applied for
90,000 cycles and the maximum rated inductive load shall be applied for 10,000
cycle a. The endurance test shall consist of the following:
Room temperature (70 percent of total).
Altitude (I5 percent of total).
Low temperature (5 percent of total).
High temperature (5 percent of total).
(e) Contaminated fuel (5 percent of total).
The cycling shall be performed at a rate of no less than 5 cycles per minute.
A cycle consists of float switc actuation on both increasing and decreasing fuel
levels. Endurance testing may be performed either by raising or lowering the float
switch in the test fluid or by clamping the float switch and raising and lowering the
test fluid. Float switches with relays shall be tested using minimum voltage applied
to the relay.
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