Insulation resistance check

Page Title: Insulation resistance check
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MIL-T-81838(AS)

When K = dielectric constant of the fuel being used.

C E = 35.5 mmf

C A = 59.6 mmf

C F obtained with MD-2 tester should be within + 1.5% of the calculated CF.

Calculated CF using nominal dielectric constant (K = 2.070) of JP-4 is:

C F = 2.070 x 35.5 x 59.6 = 133.1 mmf

4 . 6.2.4.3.2

Insulation resistance check - Resistance should be 200

megohms or greater for "A" to "B", "A" to "GND", and "B" to "GND".

4.6.3

P r e s s u r e test - The pressure relief valve and other open-

ings, except one for applying pressure shall be sealed and the tank shall be sub-

jected to the pressure tests of 4.6.3.1 or 4.6.3.2 as applicable. During these

tests, leakage of the tank shall be detected by filling the tank with air and sub-

mersion of the tank in water or by coating with a soap solution or by filling the

tank with a fluorescent dye and examining the exterior surface with an ultraviolet

lamp.

4.6.3.1

Pressure test o f individual tanks - Each production tank

shall be pressure tested to an internal negative pressure of 7 psig for 3 minutes,

an internal positive pressure of 75 psig for 3 minutes and an internal positive

pressure of 15 psig for 35 minutes. These tests shall be made without leakage or

failure except a leakage check is not required on the negative pressure test.

4.6.3.2

P r e s s u r e test f o r first article a n d sampling test - The tank

shall be subjected to 86 psig for 3 minutes and 15 psig for 15 minutes without

leakage or failure. These tests shall be conducted prior to slosh and vibration

testing (Para. 4.6.4). Following the slosh and vibration test, the tank shall be

subjected to an internal positive pressure of 112 psig for 3 minutes, a negative

pressure of 10 psig for 3 minutes and a positive pressure of 15 psig for 15

minutes without leakage or failure.

4.6.4

V i b r a t i o n a n d slosh - The tank skill be subjected to the

vibration and slosh tests as specified in MIL-V-7173 except that the 25 hours shall

consist of 12-1/2 hours in the pitch condition and 12-1/2 hours in the roll condition.

The centerline of the tank shall be at least 20 inches above the slosh axis. The

tank shall be suspended from the 30 inch lugs on an AERO-7A bomb rack. The

tank shall be pressurized to 25 psig during the test. The minimum displacement

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