MIL-R-19365E
4.7.13.2 Procedure. Following a measurement of maximum engageable resistance (see 4.7.1.2), the voltage shall be applied intermittently, 1.5 hours "on" and 0.5 hour "off", for a total of 1,000 hours ±12 hours. This voltage shall be applied to the terminals specified in 4.7.1.2. Resistance measurements (see 4.7.1.2) shall be made at the end of the
0.5 hour "off" periods after 50 hours ±4 hours, 100 hours ±8 hours, 250 hours ±12 hours, 500 hours ±12 hours, 750 hours ±12 hours, and 1,000 hours ±12 hours have elapsed. Resistors shall then be examined for evidence of mechanical damage.
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 activity within the Military Service or Defense Agency, or within the military services 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.
6. NOTES
(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)
6.1 Intended use. The resistors covered by this specification are military unique due to the fact that these devices must be able to operate satisfactorily in military systems under the following demanding conditions: 20 G's of high frequency vibration, 100 G's of shock (specified pulse), thermal shock (with no more than 1 percent deviation in initial resistance), and a low temperature coefficient of resistance. In addition, these military requirements are verified under a qualification system. Commercial components are not designed to withstand these military environmental conditions.
6.2 Ordering data. Acquisition documents must specify the following:
a. Title, number, and date of this specification, and the complete PIN (see 1.2).
b. If not otherwise specified (see 2.1), the versions of the individual documents referenced will be those in effect on the date of release of the solicitation.
c. Packaging instructions (see 5.1).
d. Bracket assembly requirements (see 6.7.1).
6.3 Qualification. With respect to products requiring qualification, awards will be made only for products which are, at the time of award of contract, qualified for inclusion in the Qualified Products List whether or not such products have actually been so listed by that date. The attention of the contractors is called to these requirements, and manufacturers are urged to arrange to have the products that they propose to offer to the Federal Government tested for qualification in order that they may be eligible to be awarded contracts or orders for the products covered by this specification. Information pertaining to qualification of products may be obtained from Defense Supply Center, Columbus, ATTN: DSCC-VQP, P.O. Box 3990, Columbus, Ohio 43218-3990
6.4 Power dissipation. Resistors are rated in accordance with 4.7.7. When higher ambient temperatures exist or when resistors are mounted in enclosures which limit ventilation, the wattage dissipation of any resistor should be reduced in accordance with figure 1, so that the maximum continuous operating temperature permissible for the resistor is never exceeded under the most severe combination of temperature conditions (see 6.8).
6.5 Spacing. When resistors are mounted in rows or banks, they should be so spaced that, taking into consideration the restricted ventilation and heat dissipation of the nearby resistors, none of the maximum permissible continuous operating temperature. An appropriate combination of resistor spacing and resistor power rating must be chosen if this is to be assured.
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