1、MIL-W -19088(SHIpS) 24 October 1955 MILITARY SPECIFICATION WATTMETERS, SWITCHBOARD TYPE, 4-1/2-INCH 1. SCOPE 1.1 Scope. - This specification covers Saritchboard electricai indicating wattmeters including 1.2 Classification. - 1.2.1 Type designation. - The type designation of wattmeters shall be in t
2、he following tom, prefixes such as, kilo and mega. and as specified (see 62). T I Component (1.2.1.1.) T Style (i. 2.1.2) 7- Color scheme (1.2.1.3) Kind of E le ctrical Special Full-scale value current units features (1.2.1.4) (1.2.1.5) (1.2.1.6) (1.2.1.7) 1.2.1.1 Component. - Wattmeters are designa
3、ted by the two-letter symbol “MR“. 1.2.1.2 Style. - The style is designated by a three digit number which signifies the following 1.2.1.2.1 -. - The first digit designates the nominal size and shape of fiange on characteristics: switchboard wattmeters as follows: 4 - 4-1/2-inch, rectangular flange.
4、1:2.1.2.2 Second digit. - The second digit designates the type of mounting and the nominal scale length in angular degrees, as follows: 9 - Flush mounting 260 degrees nominal scale. 1.2.1.2.3 Third digit.- The third digit designates either single phase or polyphase as follows: 1 - single phase 2 - p
5、olyphase (with 2 current coils and 2 voltage coils). 1 2.1.3 Color scheme. - The color scheme of the dial background, markings and pointer is designated by a single letter as follows: B - Black dial background, white markings and pointer. W - White dial background, black markings and pointer. 1.2.1.
6、4 Full-scale value. - 1.2.1.4.1 Single-range wattmeters.- The full-scale value of single-range wattmeters is represented by three figures designating the maximum number of units i full- w Thermosetting. MIL-P-78 - Plastic-Material, Laminated, Thermosetting (for Designation Plates). MIL-P-80 - Plasti
7、c Sheet, Acrylate Base, Clear, Transparent, Anti-electrostatic JAN-P-103 - Packaging and Packing for Overseas Shipment - Boxes, Wood-Cleated; JAN-P-106 - Packaging and Packing for Overseas Shipment - Boxes, Wood, Nailed. JAN-P-108 - Packaging and Packing for Overseas Shipment - Boxes, Fiberboard (V-
8、Board and W-Board) Exterior and Interior. MIL-P-116 - Preservation, Methods of. MIL-B-857 - Bolts, Nuts, Studs, and Tap-Rivets (and Material for Same). MIL-S-901 - Shockproof Equipment, Class HI (High-Impact), Shipboard Application, Tests for. MIL-E-917 - Electric Power Equipment, Basic Requirements
9、 for (Naval Shipboard Use i. MIL-S-933 - Screws, Machine, Cap and Set; and Nuts. MIL-1-1361 - Instruments, Electrical Measuring; Shunts, Resistors, and Trans- formers (Ship and Shore Use). MIL-S-6872 - Soldering Process, General Specification for. MIL-B-10377 - Boxes: Wood-Cleated, Veneer, Paper Ove
10、rlaid. MIL-L-10547 - Liners, Case, Waterproof. MIL-1-15024 - Identification Plates, Information Plates, and Marking For Identifica- MILITARY (for Indicator Dial Windows). Solid Fiberboard. tion of Electrical, Electronic and Mechanical Equipment. NAVY DEPARTMENT General Specifications for Inspection
11、of Material. STANDARDS MILITARE MIL-STD-105 - Sampling Procedures and Tables for Inspction by Attributes. MIL-STD-129 - Marking for Shipment and Storage. MIL-STD-167 - Mechanical Vibrations of Shipboard Equipment. (Copies of specifications, standards, drawings and publications required by contractor
12、s in connection with specific procurement functions should be obtained from the procuring agency or as directed by the contracting officer. ) 2.2 Other publications. - The following publications, of the issue in effect on date of invita- tion for bids, unless otherwise stated, form a part of this sp
13、ecification: CONSOLIDATED CLASSIFICATION COMMITTEE Consolidated Freight Clas sification Rule s. (Application for copies should be addressed to the Consolidated Classification Committee, 202 Chicago Union Station, Chicago 6, Ill. ) NATIONAL BUREAU OF STANDARDS Handbook H28 - Screw-Thread Standards fo
14、r Federal Services. (Application for copies should be addressed to the Superintendent of Documents, Government Printing Office, Washington 25, D. C.) 3 ;h t( *,a% “_I- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-W-L90 bb 999990b 0129b3 rl MI
15、L-W - 19088(sHIpS) 3. REQUIREMENTS 3.1 Qualification. - Wattmeters furnished under this specification shall be a product which has been tested and has passed the qualification tests specified in 4.6 (see 6.3). 3.2 Definitions. - 3.2.1 Accuracy. - The accuracy is a number which defines the limit of e
16、rror, expressed as a percentage of full-scale value unless otherwise specified herein. 3.2.1 Accuracy, rated.- The rated accuracy is a number assigned by the manufacturer to designate the accuracy classification of the wattmeter. This number, usually expressed as a percentage of full-scale ValLe, is
17、 the limit which errors will not exceed when the wattmeter is used under reference conditions. 3.2.2 Current circuit, - The current circuit is that combination of conductors and windings of the wattmeter which carries the current of the circuit in which a given electrical quantity is to be measured,
18、 or a definite fraction of that current, or a current dependent upon it. in which the pointer settles to its steady indication after a change in the value of the measured quantity. The following general classes of damped motion are distinguished: 3.2.3 Damping-. - Damping is the term applied to watt
19、meter performance to denote the manner (a) Periodic, in which the pointer oscillates about the final position before coming to rest. (b) Aperiodic, in which the pointer comes to rest without overshooting the rest position. The point of change between periodic and aperiodic damping is called critical
20、 damping. NOTE: A wattmeter is considered to be critically dampe when overshoot is present but does not exceed an amount equal to one-half the initial-accuracy requirement of the wattmeter. 3.2.4 Damping factor. - The damping factor is the ratio of the steady deflection to the dif- ference between m
21、aximum momentary deflection and steady deflection produced by a sudden ap- plication of constant electric power. All deflections are measured in angular degrees. in this specification, end-scale deflection is used as maximum momentary deflection. NOTE: The damping factor of spring-controlled wattmet
22、ers with their normal accessories, if any, is measured as the ratio of the steady deflection in angular units to the differences between angular maximum momentary deflection and the steady deflection produced by a sudden applica- tion of sufficient constant electric power to an unenergized wattmeter
23、 to obtain end-scale deflec- tion. This is the special case in which the deviation of the pointer from the position of equilibrium is the maximum value obtainable. 3.2.5 End-scale value. - The end-scale value of a wattmeter is the value of the actuating elec- trical quantity which corresponds to end
24、-scale indication. When zero is not at one end or at the electrical center of the scale, the larger value is taken. 3.2.6 Error and correction. - 3.2.6.1 Error.- The error of indication is the difference between the indication and the true value of the quantity measured. It is the quantity which, wh
25、en algebraically subtracted from the indication, gives the true value. A positive error denotes that the indication of the wattmeter is greater than the true value. 3.2.6.2 Correction.- The correction has the same numericalvalue as the error of indication, but the opposite sign. It is the quantity w
26、hich, when algebraically added to the indication, gives the true value. If the symbols T, I, E, and C represent the true value, the indication, the error, and the correction, respectively, the following equations hold: Provided by IHSNot for ResaleNo reproduction or networking permitted without lice
27、nse from IHS-,-,-!dIL-W -19088(SHIPS) EXAMPLE: A wattmeter indicates Pl2 watts when the wattage appliea to its terminals is actually 110 watts. THEN. Error = 112 - 110 = +2 watts. Correction = 110 - 112 = -2 watts. 3.2.7 External-field influence. - The external-field influence is defined as the perc
28、entage change in the indication which is caused solely by an external field of an intensity of 5 oersteds, produced by a current of the same kind and frequency as that on which the wattmeter operates, with the most unfavorable phase and position of the external field. wattmeter designed so that, whe
29、n mounted, the major portion of the wattmeter will extend behind the mountiig panel. 3.2.9 Free indication. - Wattmeters shall be considered as indicating freely if the pointer of the wattmeter under test moves simultaneously with the pointer of the standard meter with which it is being compared, wh
30、en the electrical energy supplied to both meters is gradually increased from zero to an amount sufficient to produce end-scale deflection of the wattmeter under test. fined as the percentage change in indication which is caused solely by a change of +I 10 percent from the rated frequency. 3.2.8 Flus
31、h-mounting wattmeter. - In this specification, a flush-mounting wattmeter is h 3.2.10 Frequency influence.- The frequency influence (in other than frequency meters) is de- 3.2.11 Full-scale value. - The full-scale value is equal to the largest value of the actuating electrical quantity which can be
32、indicated on the scale; or, for wattmeters having the zero be- tween the ends of the scale, the full-scale value is the arithmetic sum of the values of the actu- ating electrical quantity corresponding to the two ends of the scale. ternal magnetic field of a designated strength to the value specifie
33、d (see 3.27). Protection against magnetic fields may be inherent in the construction of the wattmeter, or it may be ob- tained by the use of a physical magnetic shield. 3.2.13. Mechanism.- The mechanism is the arrangement of parts for producing and control- ling the motion of the indicating means. I
34、t includes all the essential parts necessary to produce the results, but-does not include the case, cover, dial, or any parts, such as series resistors or shunts, whose function is to adapt the wattmeter to the quantity to be measured. 3.2.12 Magnetic shielding. - Magnetic shielding is-defined a-s l
35、imiting the effect of an ex- 3.2.14 Wattmeter, electrical-indicating. - in this specification, an electrical-indicating wattmeter is defined as a measuring device which measures the value of the quantity under ob- servation. The term “wattmeter“ is used to include not only the wattmeter proper but,
36、in addi- tion, any necessary apparatus, such as shunts, shunt leads,. resistors, reactors, condensers, or instrument transformers. 3.2.14.1 Wattmeter proper,. - The wattmeter proper is the mechanism and the scale, built into the case, including all devices, such as resistors, shunts, and so forth, w
37、hich are built into the case, or nonremovably attached to it. to indicate the operating Limitations of the wattmeter. The end-scale marking of a wattmeter does not necessarily correspond to its rating. wove as a direct result of 3.2.15 Wattmeter-rating. - The wattmeter rating is a designation assign
38、ed by the manufacturer 3.2.16 Moving element.- The moving element of a wattmeter comprises those parts which variation in the electrical quantity which the wattmeter is measuring. 3.2.17 Normal operating position. - Vertical panel mounting is the normal operating position 3.2.18 Overshoot. - Oversho
39、ot is the ratio of the overtravel of the pointer beyond its steady deflectin to the change in steady defiection when the wattmeter is suddenly energized with a new _I_- 5 for wattmeters covered by this specification. Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
40、e from IHS-,-,-MIL-W-LSOBB bb D 9999306 OL298bS MIL-W -19088(SHIFS) constant value of the measured quantity. The overtravel and deflection are determined in angular measure and the overshoot is usually expressed as a percentage. 3.2.19 Position influence (balance). - The position influence is the ma
41、ximum displacement of the pointer which is caused solely by a 60 degree inclination of the wattmeter from normal operating position in the direction which produces the most unfavorable conditions as to position. 3.2.20 Power consumption. - Power consumption is the electrical power consumed in the wa
42、ttmeter to produce end-scale deflection of the wattmeter. Power consumption may be expressed in terms of units other than units of power. 3.2.21 Response time. - This term denotes the rapidity with which the pointer comes to rest after a change of the measured quantity. It may be measured as the tim
43、e, in seconds, for the pointer to come to apparent rest after a change in the value of the measured quantity. basis of angular scale length. 3.2.22 Scale, nominal. - The nominal scale for wattmeters .at-.- - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IH
44、S-,-,-MIL-W -19088(SSJ 3.3 1 Plastic material. - 3.3.1.1 Molded thermosetting. - Molded thermosetting plastic material conforming to Speci- 3.3.1.2 Laminated thermosetting. - Laminated thermosetting plastic materials used for 3.3.1.3 Plastic windows. - Plastic material used for wattmeter windows sha
45、ll conform to fication MIL-P-14 shall be used, and shall be of the proper type for its intended use. identification plates shall conform to Specification MIL-P-78. Specification MIL-P-80. 3.3.1.4 Wattmeters shall conform to Specification MIL-E-917 with regard to the use of plastic material and other
46、 basic requirements of electric power equipment. 3.3.2 Fume-emitting material. - Material that emits deleterious or toxic fumes at 85 C. or lower shall not be used. 3.3.3 Coatings and finishes.- Coatings and firiishes which will melt, crack, chip, or scale as a result of test specified in section 4
47、shall not be used. 3.4 Desiun and construction. - 3.4.1 Balancing. - The moving element shall be balanced by a means which will provide an easy method rebalancing, such as threaded lock- or split-nuts, or a: wire helix moving along a cross arm aqd counterweight arm. The use of solder, or an adhesive
48、 such as shellac, to hold the balance weights or to function as a part of the balance weight, will not be acceptable. ponents shall be securely fastened together so that they will not separate or loosen as a result of tests specified herein. 3.4.2 Magnets.- If laminated or multiple-piece magnets are
49、 used, the laminations or com- 3.4.3 Threaded parts. - All threaded parts shall be in accordance with Handbook H28. 3.4.3.1 Bolts, nuts, and machine screws. - All bolts, nuts, and machine screws shall con- 3.4.3.2 Locking of screw-thread assemQlies. - All screw-thread assemblies shall be made form to Specification MIL-B-857 or MIL-s-933, as applicable. vibrationproo-k washers or equivalent means shall be pro- vided undbr all nuts. 3.5 Design and construction of component parts. - 3.5.1 Ca
