1、MIL-M-16125C 2lFebruary 1963 SUPERSEDING MIL-M-O016125B(SHIPS) MILITARY SPECIFICATION 6 September 1961 26 September 1951 MIL-M-16125A METERS, ELECTRICAL, FREQUENCY .This specification has been approved by the Department of Defense and is manda- tory for use by the Departments of the Army, the Navy,
2、and the Air Force. 1. SCOPE 1.1 Scope. - This Specification covers switch- board and portable electrical frequency meters for use in presenting visually the frequency of 60 or 400 cycle per second electric power system by a marked dial and pointer. l. 2 Classification. - 1.2.1 wpe designation. - The
3、 type designation of meters shall be in the following form, and as specified (see 3.24 and 6.2): Component Style Color (1.2.1.1) (1.2.1.2) scheme (1.2.1.3) 2 2 F- Center scale Frequency Special frequency range features (1.2. l. 4) (1.2.1.5) (1.2.1.6) 1.2.1.1 Component. - Meters covered by this speci
4、fication are designated by the two letter sym- bol “MR“. 1.2.1.2 Style. - The style is designated by a two-digit number which signifies the following characteristics: 1.2.1.2.1 First digit. - 1.2.1.2.1.1 Switchboard meters. - The first digit designates the normal size and shape of flange on switchbo
5、ard meters, as follows: 4 - 4-1/2 inch, rectangular flange 6 - 6 inch, rectangular flange 1.2.1.2.1.2 Portable meters. - The first digit designates the accuracy classification of portable meters, as follows: 1 - 1.5 percent 1.2.1.2.2 Second digit. - 1.2.1.2.2.1 Switchboard meters. - The second digit
6、 designates the type of mounting and the scale length in angular degrees, as follows: 8 - Flush mounting, 90 degree scale 9 - Flush mounting, 250 degree scale 1.2.1.2.2.2 Portable meters. - The second digit designates the voltage rating, as follows: 1 - 115 volts 2 - 230 volts 8 - 115 and 230 volts
7、1.2.1.3 Color scheme. - The color scheme of the dial background, markings and pointer is desig- nated by a single letter, as follows: B - Black dial background, white markings W- White dial background, black markings and pointer. and pointer. 1.2.1.4 Center scale frequency. - The center scale freque
8、ncy shall be designated as follows: 60 - For meters designed for a center scale 400 - For meters designed for a center scale frequency of 60 cycles per second. frequency of 400 cycles per second. 1.2.1.5 Frequency range. - The frequency range shall be designatedbyasingle letter, as follows: A - 59 t
9、o 61 cycles per second B - 55 or 56 to 65 cycles per second C - 390 to 410 cycles per second D - 350 to 450 cycles per second l. 2.1.6 Special features, - A single letter shall designate special features, as foilows: H - High-impact-shack resistant. Provided by IHSNot for ResaleNo reproduction or ne
10、tworking permitted without license from IHS-,-,-ML-M-16125C 1.2.1.7 Examples of type designations. - 1.2.1.7.1 Switchboard meter. - The type desig- nation MR49WOAH signifies: (a) MR - Electrical frequency meter. (b) 49 - 4 1/2 inch rectangular flange, switch- board meter, flush mounting, 250 degree
11、scale. markings and black pointer. per second. per second. (c) W - White dial background with black (d) 60 - Center scale frequency of 60 cycles (e) A - Frequency range of 59 to 61 cycles (f) H - High-impact-shock resistnt. 1.2.1.7.2 Portable meter. - The type designa- tion MRllW400 C signifies: (a)
12、 MR - Electrical frequency meter. (b) 11 - 1.5 percent accuracy class portable meter with voltage rating of 115 volts. markings and black pointer. per second. per second. (c) W - White dial background with black (d) 400 - Center scale frequency of 400 cycles (e) C - Frequency range of 390-410 cycles
13、 2. APPLICABLE DOCUMENTS 2.1 The following documents, of the issue in effect on date of invitation for bids, or request for proposal, form a part of this specification to the extent specified herein: SPECIFICATIONS MIL-M-14 - Molding Plastics and Molded Plastic Parts, Thermoset- ting. MIL-P-78 - Pla
14、stic Material, Laminated, Thermosetting (for Designa- tion Plates). HI (High-Impact), Shipboard Application, Tests for. MIL-G-3787 - Glass, Laminated, Flat; (ex- cept Aircraft). MIL-S-6872 - Soldering Process, General Specification for. MIL-E-15090 - Enamel, Equipment Light- Gray (Formula No. 11). M
15、L-E-17555 - Electronic and Electrical Equipment and Associated Repair Parts, Preparation for Delivery of. MIL,-S-901 - Shockproof Equipment, Class STANDARDS MIL-STD-105 - Sampling Procedures and Tables for Inspection by Attributes. MIL-STD-129 - Marking for Shipment and Storage. MIL-STD-130 - Identi
16、fication Marking of U. S. Military Property. MIL-STD-167 - Mechanical Vibrations of Shipboard Equipment. MIL-STD-202 - Test Methods for Electronic and Electrical Component Parts. (Copies of specifications, standards, drawings, and publications required by suppliers in connection with specific procur
17、ement functions should be ob- tained from the procuring agency or as directed by the contracting officer.) 2.2 Other publications. - The following docu- ments form a part of this specification to the extent specified herein. Unless otherwise indicated, the issue in effect on date of invitation for b
18、ids or re- quest for proposal shall apply. NATIONAL BUREAU OF STANDARDS Handbook H28 - Screw Thread Standards for Federal Services. (Application for copies should be addressed tothe Superintendent of Documents, Government Printing Office, Washington 25, D. C.) AMERICAN STANDARDS ASSOCIATION PUBLICAT
19、ION C39.1 (Application for copies should be addressed to the American Standards Association, 10 East 40th Street, New York 16, New York.) OFFICIAL CLASSIFICATION COMMITTEE Uniform Freight Classification Rules (Application for copies should be addressed to the Official Classification Committee, 1 Par
20、k Ave., at .33rd Street, New York 16, N. Y. ) 3. REQUIREMENTS 3.1 Qualincation. - Electrical frequency meter furnished under this specification shall be a product which has been tested, and has passed the qualifica- tion tests specified herein, and has been listed on Or approved for listing on the a
21、pplicable qualified prod- ucts lists. 3.2 Definitions. - Definitions which are listed in the American Standards Association Publication c39.1 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-are applicable to the various technical terms which appear
22、 in this specification, except as set forth in 3.2.1. 3.2.1 Free Indication. - Meters shall be con- sidered as indicating freely if the pointer of the me- ter under test moves simultaneously with the pointer of the standard meter with which it is being com- pared, when the electrical energy supplied
23、 to both meters is gradually increased from zero to an amount sufficient to produce end-scale deflection of the meter under test. 3.3 Material. - The material for each part shall be as specified herein. When a definite material is not specified, a material shall be used which is ade- quate for the p
24、urpose intended and for meeting the requirements herein. Acceptance or approval of any constituent material shall not be construed as a guarantee of the acceptance of the finished product. 3.3.1 Plastic material. - 3.3. l. 1 Molded thermosetting. - Molded ther- mosetting plastic material conforming
25、to MIL-M-14 shall be used, and shall be of the proper type for its intended use. 3.3.1.2 Laminated thermosetting. - Laminated thermosetting plastic materials used for identifica- tion plates shall conform to MIL-P-78. 3.3.2 Windows. - Material used for meter windows shall conform to class II of MIL-
26、G-3787. 3.3.3 Fume-emittine; material. - Material that emits deleterious or toxic fumes at 85C. or lower shall not be used. 5.3.4 Coatinns and finishes. - Coatings and finishes which will melt, crack, chip, or scale as a result of tests specified in section 4 shall not be used. 3.4 Design and constr
27、uction. - 3.4.1 Balancing. - The moving element shall be balanced by a means which will provide an easy method of rebalancing, such as threaded lock- or split-nuts, or a wire helix moving along a cross arm and counterweight arm. The use of solder, or an adhesive such as shellac, to hold the balance
28、weights or to function as a part of the balance weight, will not be acceptable. 3.4.2 Magnets. - If laminated or multiple-piece magnets are used, the laminations or parts shall be securely fastened together so that they will not separate or loosen as a result of tests specified herein. MIL-M-16125C
29、3.4.3 Threaded parts. - All threaded parts shall be in accordance with Handbook H28. Whenever practicable, all threads shall be in conformity with the coarse-thread series. The fine-thread series shall be used only for applications that might show a definite advantage through their use. Where a spec
30、ial diameter-pitch combination is required, the thread shall be in accordance with Handbook H28. 3.4.3.1 Bolts, nuts, and machine screws. - All bolts, nuts, and machine screws shall be of a corrosion-resistant material, or shall have a corrosion-resistant treatment. 3.4.3.2 Locking of screw-thread a
31、ssemblies. - All screw-thread assemblies shall be made vibra- tionproof. When practicable, split-type lock wash- ers or equivalent means shall be provided under all nuts. 3.5 Design and construction of component parts. - 3.5.1 C=. - Meter cases shall be made of molded thermosetting plastic material,
32、 metal, or other material as specified herein. The cases shall be designed and constructed with close-fitting joints to minimize the entrance of dust and moisture. The dimensions of switchboard meter cases shall be as specified. (See 3.24. ) 3.5.1.1 Portable meters. - Portable meters shall be contai
33、ned in a substantial case of hardwood, or molded plastic material. The case shall be pro- vided with durable supporting feet and a suitable carrying handle. The container shall be provided with 8 hinged cover and a snap catch. Where an auxiliary carrying case is supplied for a portable meter, it sha
34、ll be acceptable to the bureau or agency concerned. 3.5.1.2 Finish. - 3.5.1.2.1 Switchboard. - The portion of the case exposed to view from the front of the panel shall have a light gray finish in accordance with formula 11, class 2 of ML-E-15090. No nickel or other bright trimmings shall be used. M
35、etal cases shall be rendered resistant to corrosion prior to the appli- cation of the final finish. 3.5.1.2.2 Portable. - All metal fittings and trimmings shall be protected against corrosion. Wooden cases shall have a durable semitransparent finish, such as varnish. Plastic cases shall have a durab
36、le finish on the exposed portion. 3.5.1.3 Certificate. - Portable meters shall be provided with a certificate covered with clear trans- parent plastic, and attached to the case in a con- spicuous place. The certificate shall be signed by 3 Provided by IHSNot for ResaleNo reproduction or networking p
37、ermitted without license from IHS-,-,-flIL-M-lbL25C 66 W 7939906 0329220 b MIL-M-16125C a person authorized by the manufacturer and shall contain the following minimum information: (a) hbnufacturers name. (b) Type or model. (c) Serial number. (d) Date of calibration. (e) Temperature correction. (f )
38、 Accuracy classification. (B) Volt ampere burden. 3.5.1.4 Window. - Meters shall be provided with a window of glass, or other transparent mate- rial, free from discoloration, scratches, striae, electrostatic effect or other detrimental effects which may interfere in any way with normal reading of th
39、e meter in daylight. The window shall be se- cured by clamps, or by other suitable means. Ce- ment alone is not considered sufficient for holding the window in place. 3.5.1.4.1 Scale visibility. - 3.5.1.4.1.1 Switchboard meters. - The scale and window shall be so designed that when the dial is verti
40、cal the entire scale of the meter can be eas- ily read at any angle up to 45 degrees below the horizontal centerline on the vertical centerline, and 20 degrees to either side of the vertical center- line on the horizontal centerline, with general illu- mination coming from above and in front and at
41、an angle 45 degrees from the horizontal centerline. Under these conditions, there shall be no objection- able shadow on the graduated scale. 3.5.1.4.1.2 Portable meters. - The scale and window shall be so des ed that the window will extend a minimum of lrinch beyond all scale markings. 3.5.2 Dial an
42、d pointer. - 3.5.2.1 a. - The dial shall be made of stiff material firmly secured to its mounting and readily removable. The dial shall be of such material and so secured as to insure freedom from warping, fading, or other deterioration during the tests specified herein. Paper dials will be satisfac
43、tory only when adequately bonded to and backed by a metal support and when they meet all tests speci- fied herein without fading, discoloring, warping, or other deterioration. 3.5.2.1.1 SM. - 3.5.2.1.1.1 Lemth. - The scale length shall be as specified. (See 3.24. ) 3.5.2.1.1.2 Division. - The value
44、of each scale division shall, whenever practicable, be either one, 4 two, or five of the units measured or any decimal multiple or submultiple of these numbers. The angle subtended by a scale division shall be not less than O. 5 degree on portable meters, nor less than 1 degree on switchboard meters
45、. 3.5.2.2 Pointer. - The meter shall have a pointer so formed as to permit accurate readings at the usual distance from which the meter is viewed, and approximate readings up to the dis- tance of legibilityof the scale markings. The pointer shall be of rigid construction and suitable for the intende
46、d application, and shall not become damaged or distorted when subjected to any of the tests specified herein. 3.5.2.2.1 Pointer clearance (oarallax). - Where the meter is not provided with means for avoiding errors in reading due to parallax, the clearance be- tween the pointer index and the graduat
47、ed scale shall not exceed O. 10 inch, nor be less than 0.03 inch. Portable meters shall have a mirror on the dial near the scale and directly beneath the knife-edge portion of the pointer to reduce reading errors due to parallax. 3.5.3 Means of adjustment. - 3.5.3.1 Accuracy adjustment. - Meters sha
48、ll be provided with practical hop means of adjustment to accuracy. 3.5.3.2 Zero adjuster. - Instruments having spring control shall have a zero adjuster accessible from the front of the case. It shall provide for a range of adjustment above and below the zero point of not less than 3 percent of the
49、scale length and preferably shall be capable of rotating through 360 degrees without damage to any part of the instru- ment, and without becoming inoperative. If the zero adjuster is not designed for 360-degree rotation, it shall be capable of withstanding a torque of 10 ounce- inches without damage to the zero adjuster or to any part of the instrument. The zero adjuster shall have sufficient friction to prevent it from shaking loose and changing adjustment when subjected to tests specified herein. 3.5.3.3 Mechanical z
