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|  MIL-P-5238C
4.5.21 Thermal protectors. Pumps incorporating thermal protectors shall be
tested to demonstrate compliance with the design requirements. The test
procedure is the same as 4.5.23.2.1 except that the chamber temperature shall
be raised sufficiently to cause the thermal protectors to actuate.
4.5.22 Electromagnetic interference. The electrical equipment shall be
tested in accordance with MIL-STD-461 for Class Al equipment, using Method
EC03. Additional tests shall be in accordance with the detail specification.
4.5.23 Proof-of-safety tests. Tests shall be conducted to demonstrate
compliance with 3.8.1.1. The fluids to be used shall be MIL-T-5624 for pumps
operating principally in jet fuels and MIL-G-5572 for those operating in
gasoline.
.
4.5.23.1 Explosion proof. Explosion proof tests shall be conducted in accor-
dance with MIL-F-8615 using the fluids specified above.
4.5.23.2 Electrical fault containment. Sufficient tests shall be conducted
to demonstrate compliance with 3.6.2.2. These tests, as a minimum, shall
consist of a high temperature dry run (4.5.23.2.1) and a locked rotor test
(4.5.23.2.2).
For both tests, the pump shall be installed in an explosion
test chamber and electrically connected for operation. Circuit breakers or
fuses shall not be used in the external circuit. Temperatures on the inside
and outside surfaces shall be recorded throughout the test. The temperature
inside the test chamber and in the pump shall be
to 180F at the start
of the test. The explosive atmosphere shall be circulated throughout the
intenal pump passages exposed to fuel. During these tests no portion of
the surface of the pump shall reach the self-ignition-temperature of the
whichever is lesser.
fluid or
4.5.23.2.1 High temperature dry run. With the pump installed in the above
test chamber, it shall be operated dry for a sufficient length of time for
temperatures to stabilize. If the pumps contain resetting type thermal cutout
switches that are actuated during this test, at least three cycles of operating
up to cutout shall be conducted. Power shall remain applied for a sufficient
length of time after temperatures stabilize or the thermal cutout switches
actuate to assure that a safe condition prevails. If no explosion occurs, the
atmosphere inside the pump shall be ignited, and then if still safe, the out-
side atmosphere ignited, in order to demonstrate that a true hazard condition
existed during the test.
4.5.23.2.2 Locked rotor test. With the rotor locked, the pump shall be instal-
led in the above test chamber. Normal power shall be applied and maintained
until all current ceases to flow or temperatures have stabilized for 1/2 hour.
Whatever failure occurs inside the housing, shall not propagate to the outside
or ignite the explosive mixture on the outside of the housing. If no electric
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