1、, MIL-P-Z743 (2) b3 m 7779706 0073325 LI m MIL-P-28943(MC) AMENDMENT 2 20 June 1974 SUPERSEDING AMENDMENT 1 30 June 1971 MILITARY SPEC IFIC AT ION POWER SUPPLY: DIRECT CURRENT This amendment forms a part of Military Specification MIL-P-28943(MC), dated 10 March 1970, and is approved for use by all D
2、epartments and Agencies of the Department of Defense. PAGE 1 1.1: Delete in entirety and substitute the following: “1.1 This specification covers a direct current (de) power supply operating from an input voltage of either a 115/208 volt (VI, 3-phase, 4-wire, 48 to 65 hertz (Hz) alternating current
3、(ac) or a 115/208 V, single phase, 2-wire, 48 to 65 Hz ac and providing two output voltages. The output voltages shall be 10 to 18 direct-current volts (Vdc) at 5 amperes (A) and 21 to 31 Vdc at 60 A.! PAGE 2 2.1: Under “STANDARDS MILITARY“, add “MIL-STD-810 - Environmental Test Methods . II PAGE 3
4、3.3.1.1: Delete in entirety and substitute the following: “3.3.1.1 Input voltage. The power supply shall operate from a source of 115/208 V 210 percent, 3-phase, 4-wire, 48 to 65 Hz or 115/208 V - +10 percent, single phase, 2-wire, 48 to 65 Hz,“ 3.3.1.3: Add at end of paragraph: Il; each voltage sha
5、ll be regulated with 0.5 percent of desired voltage from no load to full load,“ 3.3.1.4: Delete “1.55“ and substitute 111.9511. PAGE 4 3.3.1.6: After 130-Vdc11, add “and 15-Vdc“. PAGE 5 3.3.8, line 4: Delete “15“ and substitute “30“. /- Provided by IHSNot for ResaleNo reproduction or networking perm
6、itted without license from IHS-,-,-MIL-P=28943(MC) AMENDMENT 2 PAGE 9 Table I: indicated: After “Altitute Test“, insert the following in columns as Test Ref. Para. First Article Production Sample “Fungus 4.6.11 X Test PAGE 10 XI 4.5: passed the individual production tests prior to selection for samp
7、le testing, Failure is defined as the inability of the power supply to meet the requirements specified herein. The defective power supply shall be refurbished, returned to the lot, and another random selection made for retest. The retest shall consist of the tests indicated for sample tests in Table
8、 I.! Add at end of paragraph: “Power supplies shall have successfully Failure of the sample stiall constitute rejection of the lot. 4.6.2: “4.6.2 Vibration. The power suppiy shall be tested in accordance Delete in entirety and substitute the following: with MIL-STD-810, Procedure XI.“ PAGE 11 After
9、4.6.10, add new paragraph as follows: “4.6.11 FunRuS. The power supply shall be tested for fungusproofing in accordance with method 508, procedure I, of MIL-STD-810.“ Preparing activity: Project No. 6130-N149 Navy - MC Page 2 of 2 pages - o Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
