MIL-PRF-27G
4.7.7.1.3 Printed circuit and pin-type terminals (see 3.4.3.2). Transformers and inductors shall be tested for
terminal secureness in accordance with method 211 of MIL-STD-202. The following detail and exception shall apply:
a.
Test condition - A.
b.
Applied force - Terminal secureness shall be tested by gradually applying a force of 2.0 pounds to each
pin terminal in the direction of the axis of the terminal as shown on figure 1.
4.7.7.2 Twist or bend.
4.7.7.2.1 Solid-wire lead terminals (other than printed circuit terminals). Following the test specified in 4.7.7.1.1,
transformers and inductors shall be tested in accordance with method 211 of MIL-STD-202. The following detail and
exception shall apply:
a.
Test condition - D.
b.
Application of torsion - The body of the component part or the clamped terminal shall be rotated through
360 degrees about the original axis of the bent terminal, in alternating directions, for a total of five
rotations, at the rate of approximately 3 seconds per rotation.
4.7.7.2.2 Flat solder terminals. Any terminal that shows permanent deformation greater than 15 degrees of the
metal portion of the terminal in the terminal-pull test specified in 4.7.7.1.2 shall be tested in accordance with method
211 of MIL-STD-202. This test does not apply to terminals that show permanent deformation but are not designed to
be bent 45 degrees. The following detail and exception shall apply:
a.
Test condition - B.
b.
Number of bending operations - Five times through an angle of 90 degrees (45 degrees each side of
center).
4.7.7.3 Torque.
4.7.7.3.1 Screw-thread terminals. Transformers and inductors shall be tested in accordance with method 211 of
MIL-STD-202, test condition E.
4.7.7.3.2 All other terminals. All other terminals shall be subjected to the torque specified in method 211 of MIL-
STD-202, test condition E. The torque for a terminal with a nominal diameter greater than 1/2 inch will be 160
ounce-inches. The torque shall be applied to the terminal at the point where the external lead wires normally connect
to it. The motion shall be applied clockwise and counterclockwise in a plane perpendicular to the axis of the terminal.
The equivalent diameter is equal to two times the distance from terminal center to point of wire connection after
maximum permanent deflection due to the pull test as indicated by the examples shown on figure 2. The equivalent
diameter for "hook" type terminals is the diameter of the wire from which the terminal is formed.
4.7.8 Seal (grade 4) (see 3.10). Transformers and inductors shall be tested in accordance with 4.7.8.1, 4.7.8.2, or
4.7.8.3, as applicable. Any transformer or inductor which shows evidence of leakage may be given remedial treatment.
After completion of the treatment, the seal test shall be repeated as evidence that such remedial treatment is
adequate. All other units in the lot which have been given similar satisfactory remedial treatment shall be acceptable.
4.7.8.1 Liquid-filled units. Transformers and inductors shall be heated in an oven maintained at a temperature
equal to or not more than 5°C greater than the sum of the specified maximum ambient temperature and the allowable
temperature rise (see 3.1), for not less than 3 hours for transformers or inductors weighing 20 pounds or less, and for
not less than 6 hours for transformers and inductors weighing over 20 pounds.
4.7.8.2 Gas-filled units. Transformers and inductors shall be tested in accordance with method 112 of MIL-STD-
202. The following details shall apply:
a.
Test condition letter - C.
-8
3
Leakage-rate sensitivity - 10 atm cm /s.
b.
c.
4.7.8.3 All other units. Transformers and inductors shall be immersed for 2 to 3 minutes in a bath of water (or
other suitable liquid of no greater density or surface tension) maintained at a temperature of 85°C +5°C, -0°C. The
temperature of the transformer or inductor shall not exceed 40°C at the time of immersion. (Or when specified, see
3.1, the following alternate test may be used; the transformers or inductors shall be immersed in a container of water
containing approximately 1 percent wetting agent such as Aerosol which shall then be placed in a vacuum chamber.
The pressure shall be reduced to 3.4 inches of mercury and maintained at this pressure for a period of at least 3
minutes.)
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