Downloaded from https://www.everyspec.com MIL-STD-81OD 19 July 1983 METHOD 511.2 EXPLOSIVE ATMOSPHERE TEST SECTION 11 ~-l “&EAEAIM. A test chamber capable of producing the required test conditions shall be used. Appendix A describes one type of chamber that may be used. 11-1.1 J?uQ. Unless otherwise apecified, n-hexane (i.e., normal hexane) of at .. least 95 percent purity shall be used. II-2 FOR = The teat item shall be prepared in accordance with General Requirements, 4.5.;. 11-2.1 ~ Step 1.
The test item shall be installed in the test chamber in such a manner that normal electrical operation is possible and mechanical controls may be operated through the pressure seals from the exterior of the chamber. External covers of the test item shall be removed or loosened to facilitate the penetration of the explosive mixture. Large test items may be tested one or more units at a time by extending electrical connections‘throughthe cable port to the remainder of the associated equipment located externally. Step 2.
The equipment shall be operated to determine that it is functioning properly and to observe the location of any aparking or high Q temperature components which could cause an explosion. Step 3. Mechanical loads on drive asaembliea and servomechanical and electrical loada’on switches and relaya may be simulated when pecesaary if proper precaution is given to duplicating the normal load in respect to torque, voltage, current, inductive reactance, etc. In all instancea, it ia preferable to operate the equipment as it normally functions in the system during.service use. Step 4. A thermocouple shall be ulaced on the moat massive comDonent of the test-item. , Step 5.
At leaat two thermocouples shall be placed,on the in’eideof test chamber walla. These thermocouples (from stepa 4 and 5) should be instrumented for m&itoring outaide the test chamber when the chamber ia sealed. . the .. II-2.2 dure 11 - ment test Step 1. The equipment,”or a model of the equipment of the same volume and -5 configuration, shall be placed within the caae and the caae i.natalledin the explosion chamber. ... MRTHOD 511.2 19 July 1983 511.2-6