1、MIL-V-6753A 66 7799906 0325722 T MIL-V-6753A 23 MARCEi 1956 SUPERSEDING MLV-6753 14 JUNE 1950 MILITARY SPECIFICATION VOLTMETERS, O-15d VOLT, 330 TO 1200 CYCLE, ALTERNATING CURRENT 1. SCOPE 1.1 This specification covers one type of 330 to 1200 cycle, O-150V ac moving iroi, voltmeter. 2. APPLICABLE DO
2、CUMENTS 2.1 The following specifications, stand- ards, and publications, of the issue in effect on date of invitation for bids, form a part of this specification : SPECIFICATIONS MILITARY JAN-S-44 -Shock-Testing-Mechan- ism For Electrical- Indicating Instru- ments (2Y2 and 31/2 Inch, Round, Flush Mo
3、unting, Panel- Type) MILD-5028 -Drawings and Data Lists ; Preparation of Manufacturers (For Production Aircraft, Guided Missiles, En- gines, Accessories and Other Auxiliary Equipment) MIL-P-6064 -Packaging of Light- weight Aircraft Ac- cessories MILS-7742 -Screw Threads ; Stand- MILL25142 -Luminesce
4、nt Material, e ard, Aeronautical luorescent STANDARDS MILITARY MIGSTD-129-Marking For Shipment and Storage MIGSTD-130-Identification Marking of U. S. Military Property MS33548 -Case, Instrument, 1% Dial, Standard Di- mensions For MS33558 -Numerals and Letters -Aircraft Instru- ment Dial, Standard Fo
5、rm of MS24332 -Voltmeter-O-lEiO Volt, 330 to 1200 Cycle, Alternating Current PUBLICATIONS AIR FORCE-NAVY AERONAUTICAL BULLETINS 143 -Specifications and 405 -Storage Life-Aero- (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procure
6、ment functions should be ob- tained from the procuring activity or as directed by the contracting officer.) Standards; Use of nautical Articles 3. REQUIREMENTS 3.1 Qualification.-The voltmeter fur- nished under this specification shall be a product which has been tested and has passed the qualificat
7、ion tests specified herein. This specification has been approved by the Depcvrtment of Defense and a mda- for we by the Departments of the AmU, the Navv, and the Air Force. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-6753A 66 W 7777706 0325
8、723 L W IkUL-V-6753A 3.2 Material 3.2.1 Specifications mad Standards.- Specifications and standards for all mate- rials, parts, and Government certification and approval of processes and equipment, which are not specifically designated herein and which are necessary for the execution of this specifi
9、cation, shall be selected in ac- cordance with Bulletin No. 142, except as provided in the following paragraph : 3.2.1.1 Standard parts.-AN or MIL standard parts shall be used wherever they are suitable for the purpose, and shall be identified by their part numbers. Commer- cial utility parts such a
10、s screws, bolts, nuts, cotter pins, et cetera, may be used, provided they have suitable properties and are re- placeable by the AN or MIL standard parts without alteration, and provided the corre- sponding AN or MIL part numbers are refer- enced on the drawings and in the parts list. In applications
11、 for which no suitable corre- sponding AN or MIL part is in effect on date of invitation for bids, commercial parts may be used provided they conform to the re- quirements of this specification. 3.2.2 Protective treatment.-When mate- rials are used in the construction of the volt- meter that are sub
12、ject to deterioration when exposed to climatic and environmental con- ditions likely to occur during service usage, they shall be protected against such deteri- oration in a manner that will in no way pre- vent compliance with the perf ormance of this specification. The use of any protective coat- i
13、ng that will crack, chip, or scale with age or extremes of climatic and environmental conditions shall be avoided. 3.2.3 Fluorescent Luminescent Material. -Fluorescent luminescent material shall be in accordance with MIL-L-25142, type I or III, as applicable. 3.3 Design and Construction 3.3.1 The vo
14、ltmeter shall be designed and constructed so that no parts will work loose in service. 3.3.2 The voltmeter shall be constructed so that adjustments an8 repairs can easily 2 be made by personnel of operating units and overhaul bases without the use of special tools. 3.3.3 Operational range.-The range
15、 of operation for the voltmeter shall be from 3.3.4 Case.-The case shall conform to Standard MS33548. The case shall be fabri- cated from metal. 3.3.5 Dial.-The dial shall be made of metal or of paper and shall be marked as shown on figure 1. Paper dials shall be sat- isfactory only when adequately
16、bonded to and backed by a metal support, and when they meet all the tests specified herein with- out fading, discoloring, warping, or other deterioration. 3.3.6 Bearings and pivots.-Moving ele- ments shall turn on hardened, accurately ground and highly polished steel pivots bear- ing on highly polis
17、hed first quality sapphire, diamond jewels, or other materials that have been approved as an alternate to precious gems. 3.3.7 Pointers.-The body of the pointer shall be a maximum of l/is inch wide. The entire visible portion of the pointer shall be marked with fluorescent luminescent mate- rial. 3.
18、4 Interchangeabiity.-All parts having the same nianufacturers part number shall be functionally and dimensionally inter- changeable. The drawing number require- ments of MILD-5028 shall govern changes in the manufacturers part numbers. 3.5 Performance.-The voltmeter shall be capable of satisfactory
19、operation when sub- jected to the following conditions : a. Temperatures.-Temperatures over the range of -54 to +71C. b. Humidity.-Relative humidity up to 100 percent. c. Vibration.-Vibrations incident to service use. (See 3.5.11 and 4.5.8.) d. Shock.-Shock forces as anticipated. (See 3.5.10 and 4.5
20、.15.) -54 to +7loC. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-6753A 66 = 9797706 0325724 3 MIGV-6753A L- HEIGHT OR MARKING LENGTH, INCH ALL NUMERALS o. io9 MAJOR GRADS 0109.9 SECTOR LNE - RELOW SECTOR o* O94 LETTE Ri N C O. 156 LINE AT Ii
21、SVoLTS GU ADUAT I ON MINOR GRADS I o. oc2 WIDTH OF LINE OR GRAWJATION INCH f;o,oo5 .ois METR*DIAL AND MARKING FINISH FLUORESCENT LUMINESCENT M AT E Ri AL DURARLE DULL WHITE OR NATURAL METAL DURABLE DULL BLACK - , _. *. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without li
22、cense from IHS-,-,-MIL-V-b753A 66 9999906 0325725 5 M MTGV-6753A 3.5.1 Balancing.-When spring-controlled instruments are tilted 60 from the normal vertical position, in any direction, the pointer tip shall remain within 2 percent of total scale length at the zero point, Elements free to swing shall
23、show a good mechanical balance. The balance shall be easily and readily adjustable. 3.5.2 Accuracy 3.5.2.1 Room temperature.-Unless other- wise specified, the meter shall indicate cor- rectly within $2 percent of full scale deflection at room temperature of 25 to +5“C. 3.5.2.2 Low temperature.-The c
24、hange in reading when the meter is submitted to test at -55OC. shall not exceed 6 percent of full scale value. 3.5.2.3 Frequency.-The readings shall not change more than one percent of full scale value at frequencies of 300 to 1200 cycles, from the readings observed at 400 cycles. 3.5.3 Response tim
25、e.-Response time shall not exceed 2.5 seconds when a voltage suffi- cient to give full scale momentary deflection is suddenly applied. 3.5.4 Compass eff e et cetera. 3.23.2 Cleaning.-The voltmeter shall be thoroughly cleaned, Loose, spattered, or excess solder, metal chips, and other foreign materia
26、l shall be removed during and after final assembly. 4,. QUALITY ASSURANCE PROVISIONS 4.1 Classification of tests.-The inspec- tion and testing of the voltmeter shall be classified as follows : a. Acceptance tests.-Acceptance tests are those tests accomplished on voltmeters submitted for accept- ance
27、 under contract: b. Qualification tests. - Qualification tests are those tests accomplished on samples sbbmitted for qualifi- cation as a satisfactory product. (See 4.6.) 4.2 Acceptance tests.-Acceptance tests shall consist of: a, Individual tests b. Sampling plans A and B 4.2.1 Individual tests.-Ea
28、ch voltmeter shall be subjected to the following tests as described under 4.5 TEST METHODS : a. Examination of product b. Zero adjustment c. Balancing % d. Accuracy e. Damping 4.2.2 Sampling 4.2.2.1 Sampling Plan A.-Sampling plan A tests shall be performed on voltmeters selected at random in accorda
29、nce with the following method : Samples Lot 1 1 to 50 2 51 to 200 3 201 to 1000 1 Each additional 1000 4.2.2.1.1 Sampling plan A shall consist of the following tests as described under 4.5 TEST METHODS : a. Individual tests b. Response time c. Compass effect d. Vibration e. Temperature influence f.
30、Dielectric 4.2.2.2 Sampling Plan B.-Unless other- wise specified, three voltmeters shall be selected at random from the first 10 items produced under contract or order and sub- jected to the following tests as described under 4.5 TEST METHODS : a. Individual tests b. Sampling plan A c. Heat effect a
31、t 71OC I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-6753A bb - 99999Ob 0325728 O d. Low temperature exposure e. Sustained load f. Humidity resistance g. Shock h. Mounting lugs 4.3 Rejection and Retest.-When one or more items from a lot fai
32、l to meet the speci- fication, acceptance of all items in the lot will be withheld until the extent and cause of failure are determined. After corrections have been made, all necessary tests shall be repeated. 4.3.1 Individual Tests May Continue.- For production reasons, individual tests may be cont
33、inued pending the investigation of a sampling test failure. But fuial acceptance of the entire lot shall not be made until it is determined that the lot meets all the re- quirements of the specification. 4.3.2 Defects In Items Already Accepted. -The investigation of a test failure could indicate tha
34、t defects may exist in items al- ready accepted. If so, the contractor shall fully advise the procuring activity of all de- fects likely to be found and methods of cor- recting them. 4.4 Test Conditions.-Unless otherwise specified, the voltmeter shall be tested at room temperature of 25 -f- 5C. 4.4.
35、1 Tapping.-Either the voltmeter or its support shall be tapped lightly in taking readings except when ascertaining the effect of friction after vibration. 4.5 Test Methods. 4.5.1 Examination of Product.-The volt- meter shall be inspected to determine com- pliance with this specification with regard
36、to material, workmanship, and marking. 4.5.2 Zero Adjustment.-The voltmeter shall be checked for zero adjustment. The limits of the zero adjustment shall be as specified in 3.7. 4.5.3 Balancing.-The pointer shall be set to the center of the zero scale division with the meter in a vertical position.
37、The instru- NIIGV-6753A ment shall then be tilted 60 from the verti- cal in any direction and the position of the pointer shall not deflect more than the amount specified in 3.5.1. 4.5.4 Accuracy.-Each meter shall be calibrated to determine the accuracy of the instrument at room temperature. The ac-
38、 curacy may be checked at any reading on the scale and shall be within 2 percent of full scale deflection. 4.5.5 Damping.-Voltage sufficient to produce momentary full scale deflection shall be applied to the meter. The maximum momentary deflection shall be taken and re- corded. After the pointer has
39、 come to rest, the steady deflection shall be taken and recorded. The damping factor shall be taken as the ratio of the steady deflection in angu- lar degrees to difference between the maxi- mum momentary deflection and the steady deflection in angular degrees, 4.5.6 Response time.-Voltage sufficien
40、t to produce momentary full scale deflection shall be applied to the meter. The length time, in seconds, required for the pointer to come to rest shall be noted. This test shall be repeated several times and the average value taken as the response time of the meter. The pointer is to be considered a
41、s having come to apparent rest when it has reached the actual rest point within *I percent of the scale length. 4.5.7 Compass effect.-The meter shall be rotated in a vertical plane about a short bar magnet type compass and with the near- est part of the indicator 5 inches from and magnetically east
42、or west of the center of the compass. Starting directly under the com- pass, the meter shall be held in position O, 45O, 90, 135O, 180, 225O, 270, and 315 from the initial position. At each of these positions the meter shall be in its normal upright mounting position, The horizontal magnetic field i
43、ntensity shall be 0.17 to 0.19 oersted. 4.5.8 Vibration.-Meters shall be sub- jected to vibration of 24 hours consisting of 7 . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-6753A 66 m 7777906 0325729 2 RIIL-V-6753A 8-hour periods in each of
44、the following 3 positions : Position 1-Normal vertical mounting Position 2-Rotated 90 counterclock- Position 3-Horizontal plane with face The construction of the vibrating platform shall be such as to give simple harmonic motion at a frequency of 400 cycles per minute and with an amplitude of l/ie i
45、nch at the horizontal center line of the meter. 4.5.8.1 Meters shall also be mounted on a vibration stand giving a frequency be- tween 500 and 2500 vibrations per minte of such a character that a point on the meter case will describe, in a plane inclined 45O to the plane of the face, a circle with a
46、 di- ameter of not less than 0.018 inch nor more than 0.020 inch. The meter shall be vibrated for a total of 2 hours at any desired fre- quency between 500 and 2500 vibrations per minute, but shall not be vibrated at any one frequency for more than 30 minutes. The meter shall be successively deflect
47、ed to ap- proximately 5 equidistant points on the scale during this test. In no case, however, shall the pointer be held at any given scale mark for more than 30 minutes. 4.5.8.2 At the conclusion of the vibration test the meter shall be connected to a course of potential and readings taken througho
48、ut the calibrated scaIe; the readings to be taken on both an ascending and descending scale, the latter to observe the effect of fric- tion. The errors due to vibration shall not exceed the values specified in 3.5.11. 4.5.8.3 The condition of the pivots and bearings after the vibration tests shall b
49、e observed through a microscope of at least 40 diameters, 4.5.9 Temperature influence. - Meters shall be tested at 2OoC above and below 25OC. Readings shall be taken at not less than 5 points (approjimately equidistant) on the scale, including maximum scale value position. wise in plane of mounting. upward. and the temperature influence computed. The temperature influence shall be con- sidered one-half the percentage change in indication caused by the 20 departures
