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|  MIL-C-18312F
3.4.2 Case. Each capacitor shall be enclosed in a hermetically sealed metal case that will protect the capacitor
element from moisture, impregnant leakage, and mechanical damage under the test conditions specified herein.
The use of exterior cardboard sleeves for insulating purposes will not be permitted.
3.4.3 Capacitor element. The capacitor element shall consist of metallized paper, paper plastic, or plastic film.
The capacitor element may be separated by uncoated dielectric tissues.
3.4.3.1 Construction. All capacitors shall have extended electrode construction to minimize inductance.
3.5 Seal.
3.5.1 Liquid or solid impregnated capacitors. When capacitors are tested as specified in 4.7.2, there shall be no
evidence of repetitive bubbling.
3.5.2 Liquid-filled capacitors. When liquid-filled capacitors are tested as specified in 4.7.2, there shall be no
evidence of liquid leakage.
3.6 Dielectric withstanding voltage. When tested as specified in 4.7.3, capacitors shall be capable of withstanding
the dc potentials specified (see 3.1) without permanent damage, or open-circuiting or short-circuiting. Momentary
breakdowns (see 6.6.2) will be permitted.
3.7 Capacitance. When measured as specified in 4.7.4, the capacitors shall be within the tolerance of the
nominal value specified (see 3.1).
3.8 Dissipation factor. When measured as specified in 4.7.5, the dissipation factor of the capacitors shall not
exceed the value specified (see 3.1).
3.9 Insulation resistance (see 6.6.2).
3.9.1 Terminal to terminal. When measured as specified in 4.7.6, the product of the nominal capacitance,
expressed in microfarads (F), and the insulation resistance, expressed in megohms, shall be not less than the
values specified (see 3.1), as applicable.
3.9.2 Terminal to case. When measured as specified in 4.7.6, where the case is not a terminal, the insulation
resistance between terminal and case shall be not less than the value specified (see 3.1).
3.10 Barometric pressure (reduced) (qualification only). When tested as specified in 4.7.7, capacitors shall
withstand a dc potential equal to 125 percent of rated dc voltage without visible damage, external flashover, or open-
circuiting or short-circuiting.
3.11 Vibration. When capacitors are tested as specified in 4.7.8, there shall be no intermittent contacts of 0.5
millisecond (ms) or greater duration, or momentary arcing, or other indication of breakdown, nor shall there be any
open-circuiting or short-circuiting or evidence of mechanical damage (see 6.6.2).
3.12 Salt spray (corrosion). When capacitors are tested as specified in 4.7.9, there shall be no harmful corrosion,
and at least 90 percent of any exposed metallic surfaces of the capacitor, shall be protected by the finish. Harmful
corrosion shall be construed as being any type of corrosion which in any way interferes with mechanical or electrical
performance. There shall be no unwrapping of or mechanical damage to insulating sleeves. In addition, corrosion
of the terminal hardware or mounting surface shall not exceed 10 percent of the surface area. Marking shall remain
legible.
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