1、r 1 EIA 155-B 70 I 3234600 0028386 1 m .- -s /- Y EIA -STANDARD Fixed Wirewound Pow er Resistors RS455-B (Revision of RS-155-A) Engineering Department ELECTRONIC INDUSTRIES ASSOCIATION EIA 155-6 70 m 3234b00 0028387 3 m NOTICE EIA engineering standards are designed to serve the public interest throu
2、gh eliminating mis- understandings between manufacturers and purchasers, facilitating interchangeability and improve- ment of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such standards shall not in any r
3、espect pre- clude any member or non-member of EIA from manufacturing or selling products not codorming to such standards, nor shall the existence of such standards preclude their voluntary use by those other than EIA members whether the standard is to be used either domestically or internationally.
4、Recommended standards are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, ETA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the recommended sta
5、ndards. Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 2001 Eye Street, N.W., Washington, D. C. 20006 Electronic Industries Association 1970 Ail rights reserved PRICE $3.60 Printed in U.S.A. c a a EIA 155-B 70 m 3234b00 0028388 5 m FIXED WIREWOUND POWER RESISTORS (From EIA Sta
6、ndard RS-15.5 and Standards Proposal No. 1034, formulated under the cognizance of EIA Working Group P-1.4 on Wirewound Resistors.) SCOPE This Standard covers fixed wirewound power type resistors with initial tolerances of 1% and 5% of 3 styles and 24 power ratings. Standard ratings, tolerances, and
7、test requirements are included, 1. RESISTOR STYLES 1.1 1.2 1.3 2.1 Strip Style - CRW20 through CRW24 - see page 3. 1.1.1 Strip Style - CRW 17 through CRW 19 - see page 4. Tubular, Open End Style - see page 5. Axial Lead Type - see page 6. 2. ELECTRICAL CHARACTERISTICS AND STYLES Type Designation Typ
8、e designation shall be in the following form: T Style L Characteristic 1002 Resistance -r T Tolerance RS-155B Page 1 2.1.1 Style - The style is identified by a three letter symbol CRW or NRW (applicable to axial lead styles only) followed by a two digit number. Throughout this specification, referen
9、ce to CRW on the axial styles will also imply NRW. The CRW letters identify EL4 Standard style of power type wirewound fixed resistors and the NRW letters identify EIA Standard style power wirewound non-inductively wound fixed resistors. The number identifies the size of resistor. 2.1.2 the characte
10、ristics of the unit as shown on Table I. Characteristic - The characteristic designation is a one-letter symbol which identifies 2.1.3 Resistance - The nominal resistance value in ohms is identified by a four digit number. The fist three digits represent significant figures and the last digit specif
11、ies the number of zeros to follow. Where fractional values of an ob are required the letter R shall be substituted . - EIA 155-B 70 3234600 0028389 7 RS-1.55-B Page 2 TABLE I. CHARACTERISTIC H V a 350C 350C For Temp. 260PPM/“C for above 25C: .258 per sq. in. OI30PPMr C, of winding 208 & above, area
12、& above, t5OPPM 5 to 208, IOOPPM below. 100PPM below 58. For Temp. below 25C: O+OPPM/C, Sil &above, f 1 OOPPM below 58. o .2 0.2 1 2 1 1 2 3 5 5 0.3 0.2 E G Max. Ambient Temp, 350C 275C O+SOPPM/“C, 20il & above, f5OPPM 5 to 208, 100PPM below Sil OI30PPM/“C, 208 & above, ISOPPM 5 to 20!2, 1OOPPM belo
13、w 58 Temp, Coefficient Diel. Strength Vibration o .2 0.5 O .5 1 3 o .2 o .2 0.5 0.5 1 1 0.2 *An additional 0.05s2 is added to the percent change in each test to allow for resistance measurement error. TABLE II. STANDARD VALUES Standard Values for 5% Tolerance Standard Values for 1 % Tolerance 2.15 3
14、.16 2.2 1 3.24 2.26 3.32 2.32 3.40 2.37 3.48 2.43 3.57 2.49 3.65 2.55 3.74 2.6 1 3.83 2.67 3.92 2.74 4.02 2.80 4.12 2.87 4.22 2.94 4.32 3.01 4.42 3.09 4.53 4.64 4.75 4.87 4.99 5.1 1 5.23 5.36. 5.49 5.62 5.76 5.90 6.04 6.19 6.34 6.49 6.65 6.8 1 6.98 7.15 7.32 7.50 7.68 7.87 8.06 8.25 8.45 8.66 8.87 9
15、.09 9.3 1 9.53 9.76 1.47 1.50 1.54 1.58 1.62 1.65 1.69 1.74 1.78 1.82 1.87 1.91 1.96 2.00 2.05 2.10 1 .o0 1 .o2 1 .o5 1 .O7 1.10 1.13 1.15 1.18 1.21 1.24 1.27 1.30 1.33 1.37 1.40 1.43 Notes: 3.3 3.6 3.9 4.3 4.7 5.1 5.6 6.2 6.8 7.5 8.2 9.1 1 .o 1.1 1.2 1.3 1.8 2.0 2.2 2.4 2.7 3.0 - Values not shown w
16、ill be considered nonstandard. 1 to 10 decade shown, use decade multipliers for the other values. - EIA 155-B 70 = 3239600 0028390 3 RS-155-B Page 3 1. RESISTOR STYLES 1.1 Strip Style .O85 Dia. Min. .O15 Min. Thickness 1 .O00 f .I 25 .I96 k .O50 Dia. 2 Holes .656 Max. +.I56 C .437 f.031 - .O62 I RS-
17、1.55-B . Page4 1.1.1 Strip Style CRW .O62 f .O1 5 Dia. .O15 Min. Thickness 2 Holes Min. Clearance Between , Coating and Hole Edge .O1 5 / .12E15 L.125 f .O10 Dia. 2 Holes k- 4 C k .O62 .250 +.O31 -.o007 I III Max. .O94 Min. II When units are to be stacked, a 3/32 washer is to be inserted between uni
18、ts. -CRW 17 I .750 I CRW 18 I 1.000 CRW 19 I 2.000 Dimensions BIC 1.000 1.312 1.250 1.562 2.312 2.625 Wattage 10 15 20 Notes: 1. Available only in characteristics H and V. 2. The minimum resistance value is 1.0 ohm. 3. Should not be subjected to high frequency vibration. 4. To achieve rated wattage,
19、 unit must be mounted on an area 10 x 10 steel .O40 thick. Maximum Value a- 3.65 K 6.08 K 18.24 K EIA 155-B 70 W 323VbOO 0028372 7 W Wattage 11 14 17 26 55 78 113 159 210 RS-155-B Page 5 Maximum Resistance Value 5.62 K 6.34 I 1 OK 18.2 K 40.2 K 56.2 K 90.9 K 140K 182K 1.2 Tubular, Open End Style 1.3
20、12 , 1.312 1.312 .172 To .328 It .O85 Dia. Min. Minml r/- 2 Holes .O16 Min. -0- C ,ions Dimei B .500 Style CRW29 CRW3 1 A CID 1.750 172 1 .625 1.500 .594 .5 94 CRW32 2.000 CRW33 .594 3.000 4.000 4.000 .187 CRW35 .906 CRW36 1.312 6.000 CRW37 CRW38 CRW47 8.000 10.500 Notes: 1. Available only in charac
21、teristic H and V. 2. The minimum resistance value is 1.0 ohms. 3. Should not be subjected to high frequency vibration. 4. Mounting hardware is detailed in MS 75009 (Military Standard) open end style through bolt and bracket assembly. EIA 155-B 70 3234600 0028393 9 RS-155-8 Page 6 1.3 Axial Lead Type
22、 C J I I - Style Dimensions Maximum Resistance Value Wattage Notes Characteristic Characteristic B C G E,H&V . G E,H&V A #i8 or Nominal .312f .O62 #20AWG 5 6.5 12.1K 3.65K CRW57 1 .O94 #18 or Nominal .344f .O94 #20AWG 10 11 -t .O62 1*875- 39.2K 8.25K CRW58 CRW59 .187 f .O62 #i8 or #20 AWG Nominal 2.
23、5 3 3.57K 715a ,500 i .O62 _ .3 12 f ,062 #i8 or #20 AWG Nominal 46 5 6.5 12.1K 3.65K CRW67 CRW68 CRW69 1 i .O94 #i8 or- Nominal .3u+ .o94 #20AWG 10 11 1,875 + - .I25 39.2K 8.25K 46 6 #i8 or Nominal .187f .O62 #20AWG 2.5 3 3.57K 715a SOO f .O62 .094f .O31 I giny I 1 1.25 I 1.4K 267a 56 CRW7 1 ,406 f
24、 .O31 Notes: The minimum resistance value for aii styles is 1.0 ohm. 2Styles CRW57 and 58 should not be exposed to high frequency vibration. 3Styles CRW57,58 and 59 are uninsulated and should not be subjected to Dielectric Strength or insulation resistance. 4The body of styles CRW67 and 68 should be
25、 clamped or restrained when exposed to High Frequency Vibration. 6NRW Styles will have maximum resistance values of 1/2 the maximum resistance of inductive styles. style CRW71 the length of the body is based on defining the end of the body as a point where the diameter reaches .O60 inches. - , - . _
26、- _- &- EIA 155-8 70 m 3234b00 O028394 O m RS-155-B Page 7 for one of the significant digits to represent the decimal point. When the letter R is used the last digit becomes significant, as shown in the following example: 56R5 = 56.5 ohms 2.1.4 Resistance Tolerance - The resistance tolerance is iden
27、tified by a single letter in accordance with Table III. TABLE III. RESISTANCE TOLERANCE I Symbol I Resistance Tolerance I 3. REQUIREMENTS 3.1 Design and Construction - Resistors shall be of sound design and construction. They shall be capable of meeting the test requirements and the physical dimensi
28、ons specified for their particular style. Each resistor shall consist of a wirewound resistance element protected against exposure by an enclosure or coating of moisture resistant insulating material. A single layer resistance winding shall be used. 3.2 Terminals - All terminals shall be suitably tr
29、eated to facilitate soldering. They should be solderable as defined in Mil-STD-202, Method 208 to within .O62 inch of the resistor body on axial leads and .125 inch on lug terminals. 3.3 Winding 3.3.1 Wire - The wire shall have no joints, welds, or bonds, except at the end terminals. The wire shall
30、possess a uniform cross section and shall be as free as practicable from particles or impurities. The cross sectional area of the wire shall be the maximum possible with other requirements specified herein and in no case shall the nominal diameter be less than .O0 1 inch. 3.3.2 Pitch for Round Wire
31、- The average winding pitch shall not exceed 500% of the wire diameter. 3.3.3 Effective Wire Coverage - Effective Wire coverage is the winding length between points of departure from the normal winding pitch. The effective wire coverage should be a minimum of 80% of the total design winding area. 7-
32、 c EIA 155-B 70 W 3234b00 0028395 2 RS-155-B Page 8 3.3.4 Protection - The resistance element of resistors shall be protected by a coating or enclosure which shall completely cover the exterior of the resistance element. a 3.3.5 Power Rating - The resistors shall be capable of dissipating the rated
33、wattage at 25C in still air and without the aid of a mounting heat sink. When operated in an ambient above 25“C, derating shall be applied as specified in Table IV. When operated according to this table, there should be no mechanical deterioration or degradation of the protective coating. TABLE IV ?
34、 s a n 5 ? u, O ? 1 O0 75 50 25 O 25 75 125 175 225 275 350 AMBIENT TEMP. DEG. CENTIGRADE 3.3.6 general inductance classifications. (See Paragraph 4.2.1 1 for inductance test.) Inductance - The axial lead style resistors covered by this specification can be of two Inductive Winding - Standard single
35、 layer winding. Non-Inductive Winding - Two concentric windings, each layer having twice the nominal resistance of the resistor. Both layers having the same pitch but wound.in opposite directions with the crossover points lying in axial directions. Other non-inductive winding methods may be used. No
36、n-inductive styles shall have a maximum resistance value of 1/2 the mhximum resistance of inductive styles. 3.4 Marking Resistors shall be marked with the.information listed below. Where space limits the amount of printing, the priority should be as listed. (a) EIA Type designation (b) Manufacturers
37、 name or trade mark (c) EIA Code for date of manufacture (d) Resistance value EIA 155-B 70 W 3234600 0028396 4 = RS-155-B Page 9 4. STANDARD TESTS Parts described by this specification shall be capable of meeting the test requirements listed below. 4.1 tests are to be made or referred to are as foll
38、ows: Standard Test Conditions - Unless otherwise specified the atmospheric conditions at which Temperature 25C f 5C. Barometric Pressure 30 f 2 inches of Hg. Relative Humidity less than 60%. 4.2 shown in Table V and the groups given the tests in the order specified. Test Requirements - When tests ar
39、e conducted the samples should be divided into groups as TABLE V _ Test Group I Temperature Coefficient Dielectric Strength Thermal Shock Momentary Overload Moisture Resistance Terminal Strength Group II Load Life Group III High Frequency Vibration Test Paragraph 4.2.3 4.2.4 4.2.5 4.2.6 4.2.1 4.2.8
40、4.2.9 4.2.10 4.2.1 Visual and Mechanical Inspection - Resistors shall be inspected to verify that the physical dimensions, construction, and marking are in accordance with the applicable detail requirements. 4.2.2 Resistance - DC resistance shall be measured to determine if it is within the specifie
41、d tolerance. A resistance bridge with a calibrated accuracy of O. 1% or closer shall be used and the application of voltage shall be such that less than 10% of rated wattage is applied. The period of application of the measurement voltage shall be 5 seconds or less. The axial lead resistors with the
42、 resistance value below 20 ohms shall be measured at a point on the lead .375 f .O62 inch from the resistor body. - - EIA 155-B 70 3234600 0028397 b RS-155-B Page 10 a 4.2.3 Temperature Coefficient - Resistance shall be measured at 25 f 2C. The resistors shall then be maintained for 30 to 45 minutes
43、, within 2“C., at each of the ambient temperatures in the order listed in Table VI. TABLE VI Temperature Coefficient Ambient Temperatures “C . -55 25f2 125 275 3350 Notes: succeeding extreme temperatures. This temperature shall be considered the reference temperature for each of the 2This temperatur
44、e applicable only to Char. G. 3This temperature applicable only to Char. E, H and V. At the end of each period, the resistance shall be measured at the temperature maintained during the period. The temperature coefficient of resistance, referred to a reference temperature of 25“C., shall then be com
45、puted as follows: (R - r) 100 Where: TC = (tR - t,) R TC = Temperature Coefficient in percent per degrees C. R = Resistance at reference temperature. r = Resistance at test temperature. . tR = Reference temperature in degrees C. t, = Test temperature in degrees C. Resistors shall not be damaged by t
46、he exposure to the extreme temperatures and the temperature coefficient shall not exceed that specified in Table I. 4.2.4 Dielectric Strength - (Not applicable to Styles CRW57, 58, and 59). An alternating current potential of 1000 Volts (except for the CRW70 which shall be 500 Volts) RMS Commercial
47、line frequency shali be applied for one minute between the terminals connected together and the hardware or conductive materials. Lug resistors shall be mounted by their normal mounting hardware without supplementary - - -. - -_ _ / - I K EIA l155-B 70 W 323ebOO 0028398 8 W RS-155-B Page 11 insulati
48、on. Axial lead resistors shall be placed on a conductive material which will conform to the resistors surface so that at least 90% of the outer periphery is contacted. Resistors shall not flash over or show evidence of breakdown, and the change of resistance shall not exceed +(0.2% + .Osa). 4.2.5 Th
49、ermal Shock - After a DC Resistance measurement, rated power should be applied to each resistor until thermal stability is reached. The power shall then be removed and within 12 seconds, the resistors shall be subjected to an air temperature of -55 I5”C for a period of not less than 15 minutes. Resistance shall again be measured after the units have stabilized at room temperature. Resistors shall not show any evidence of mechanical damage and resistance change shall not exceed that specified in Table I. 4.2.6 Momentary Overload
