MIL-R-93 Resistors, Fixed, Wire-Wound, Accurate, General Specification ForThis specification covers the general requirements for accurate, wire-wound, fixed resistors having a maximum resistance tolerance of 1 percent, with the winding protected against high humidity. The resistors are rated for continuous full load operation at any ambient temperature up to 125 Degrees C, and derated up to 145 Degrees C. They are not capable for application where alternating current ac characteristics are of critical importance. Performance characteristics are in accordance with table I.

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MIL-R-93F

4.7.17  Vibration, high frequency (see 3.21).  Resistors shall be tested in accordance with method 204 of MIL-STD-202.  The following details and exceptions shall apply:

a.  Mounting of specimen:  Resistors shall be mounted in relation to the test equipment in such a manner that the stress applied is in the direction which would be considered most detrimental.

(1)  Wire lead terminal resistors:  Resistors shall be rigidly mounted on appropriate jig fixtures with their bodies restrained from movement and their leads supported at a distance of 0.25 inch from the resistor body.  These fixtures shall be constructed in a manner to insure that the points of the resistor mounting supports will remain in a static condition with reference to the vibration table.

b.  Test leads:  Test leads used during this test shall be no larger than AWG size 22 stranded wire, so that the influence of the test lead on the resistor will be held to a minimum.  The test lead length shall be no longer than necessary.  A shielded cable, which may be necessary because of the field surrounding the vibration table, shall be clamped to the resistor mounting jig.

c.  Measurement before vibration:  DC resistance shall be measured as specified in 4.7.2. d.  Test condition:  D.

e.  Motion:  In each of three mutually perpendicular planes; the initial plane shall pass through the resistor axis and terminals, and the other two planes shall be mutually perpendicular.

f.   Measurement during vibration:  Each resistor shall be monitored to determine electrical discontinuity by a method which shall at least be sensitive enough to monitor or register, automatically, any electrical discontinuity of 0.1 millisecond or greater duration.

g.  Measurement after vibration:  DC resistance shall be measured as specified in 4.7.2.

h.  Examination after test.  Resistors shall be examined for evidence of mechanical and electrical damage.

4.7.18  Fungus (see 3.22).  Unless certification is provided, resistors shall be tested in accordance with method 508 of MIL-STD-810.  Resistors shall be examined for evidence of fungus growth.

5.  PACKAGING

*                5.1  Packaging.  For acquisition purposes, the packaging requirements shall be as specified in the contract or order (see 6.2).  When packaging of materiel is to be performed by DoD or in-house contractor personnel, these personnel need to contact the responsible packaging activity to ascertain packaging requirements.  Packaging requirements are maintained by the Inventory Control Point's packaging activities within the Military Service or Defense Agency, or within the military service's system commands. Packaging data retrieval is available from the managing Military Department's or Defense Agency's automated packaging files, CD-ROM products, or by contacting the responsible packaging activity.

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