MIL-PRF-49462C
4.8.10 Insulation resistance (see 3.15). Resistors shall be tested in accordance with method 302 of
MIL-STD-202. The following details and exceptions shall apply:
a. Special preparations: As specified in 4.8.9.1a.
b. Test condition letter: A or B, whichever is practicable.
c. Points of measurement: Between the resistor terminals connected together and the V-block.
4.8.11 Moisture resistance (see 3.16). Resistors shall be tested in accordance with method 106 of
MIL-STD-202. The following details and exceptions shall apply:
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a. Mounting: Soldered by their leads to rigid mounts or terminal lugs. The spacing of the mounts or
terminals lugs shall be such that the length of each resistor is approximately .375 inch when
measured from the edge of the supporting terminal to the resistor body. One half of the sample
units shall be covered with a V-shaped metal strap whose width is .750 inch or equal to the body
length, whichever is less (see figure 1). The strap shall be made of a corrosion resistant metal and
shall be kept in contact with the resistor body by supporting the body with a nonconducting,
noncorrosive support whose width is less than that of the body and which will not act as a moisture
trap. The mounting straps may be individual for each resistor or continuous for all resistors.
b. Polarization and loading voltage:
(1) Polarization: During steps 1 to 6, inclusive, a 100 volt dc potential shall be applied only to
those resistors which have a polarizing strap. This potential shall be applied with the positive
lead connected to the resistor terminals tied together, and the negative lead connected to the
polarizing straps.
(2) Loading voltage: During the first 2 hours of steps 1 and 4, a dc test potential equivalent to 100
percent rated wattage, but not exceeding 500 volts dc shall be applied to those resistors which
are mounted by their leads without the polarizing straps specified in 4.8.11a.
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c. Subcycle: Step 7a shall be performed during any five of the first eight cycles only. All polarizing
straps may be removed to perform step 7a and shall then be replaced prior to returning the
resistors tot he humidity chamber.
d. Final measurements: Upon completion of step 6 of the final cycle, the resistors shall be held at
the high humidity condition and at a temperature of +25°C ±2°C for a period of 1 hour 30 minutes
to 3 hours 30 minutes. The same straps used for polarizing the resistors may also be used for the
dielectric withstanding voltage and insulation resistance tests. Resistors shall be removed from
the chamber and within 30 minutes, without any additional handling, the dc resistance, dielectric
withstanding voltage, and insulation resistance shall be measured in that order as specified in
4.8.2, 4.8.9, and 4.8.10 respectively. The sample units shall not be subjected to forced circulating
air during the tests.
e. Examination after test: Resistors shall be examined for evidence of mechanical damage.
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