Disclosure to Promote the Right To Information

Transcription

1 इ टरन ट म नक Disclosure to Promote the Right To Information Whereas the Parliament India has set out to provide a practical regime right to information for citizens to secure access to information under the control public authorities, in order to promote transparency and accountability in the working every public authority, and whereas the attached publication the Bureau Indian Standards is particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit education and knowledge, the attached public safety standard is made available to promote the timely dissemination this information in an accurate manner to the public. ज न1 क अ+धक र, ज 1 क अ+धक र Mazdoor Kisan Shakti Sangathan The Right to Information, The Right to Live प0र 1 क छ ड न' 5 तरफ Jawaharlal Nehru Step Out From the Old to the New IS (1984): Variable Resistors, Part 4: Preset, Section 4: Type VRT 4 P [LITD 5: Semiconductor and Other Electronic Components and Devices]! न $ एक न' भ रत क +नमण Satyanarayan Gangaram Pitroda Invent a New India Using Knowledge! न एक ऐस खज न > ज कभ च0र य नहB ज सकत ह ह Bhartṛhari Nītiśatakam Knowledge is such a treasure which cannot be stolen

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4 UDC: IS : 8872 ( Part 4/Set 4 ) 1984 India/z Standard SPECIFICATION FOR VARIABLE RESISTORS PART 4 PRESET Section 4 Type VRT 4 P 0. General This standard shall be read in conjunction with IS : 88?2 ( Part 1 ) 1977 Specification for variable resistors: Part 1 General requirements and methods tests. c 1 ~scope _ This standard covers the requirements cermet (nonwire wound ) multiturn presets. 2. Outline, Drawing aud Dimensions The outline, drawing and dimensions shall be according to Fig. 1. 2tl.5 FiG. 1 OUTLINE, DRAWING AND DIMENSIONS Adopted SO November 1984 May 1985, IS1 INDIAN STANDARDS INSTITUTION MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHIl I Gr. 5

5 IS : 8872 ( Part 4/Set 4 ) Characteristics a) Climatic category b) Low air pressure c) Acceleration d) Bump e) Vibration f) Shock g) Preferred resistance values h) Rated working voltage j) Selection tolerance k) Rated dissipation at 70 C m) Temperature characteristic resistance n) Stability after endurance electrical p) Maximun surface temperature q) Effective electrical travel 55/100/56 2 kpa 1 km/s bumps 10 to Hz, 200 m/s2 1 km/s2 See Table 1 See Table I f 10 percent 0.5 W (see Note) f 100 ppm/ C, f 250 ppmrc f 2 percent 125 C 15 turns Min 20 turns Max r) Typical construction Cermet ( nonwirewound ) Note For ratings at temperatures other than 7O C, reference shall be made to the derating curve shown in 3. TABLE 1 PREFERRED RESISTANCE VALUES AND RATED WORKING VOLTAGES Resistance Rated Working Voltage V 100 D 200 n 470 sz lk 2.2k Q 4*?k bb 10k B 22k Q 47k 9 1OOk n 220k rlz 470k Q IM D

6 IS : 8872 ( Part 4/Set 4 ) Derating:Curve Marking See 6 IS : 8872 ( Part 1 ) In addition, the temperature coefficient shall also be marked. 5. Material, Construction and Workmanship See 5 IS : 8872 ( Part 1 ) s 6.1 ClassiJca tion s Type tests The sequence type tests and requirements shall be in accordance with Table The manufacturers shall submit 48 samples in each style for which the approval is required, having the numbers and values as follows : a) 14 samples the highest value, and 2 spares; b) 14 samples the lowest value, and 2 spares; and c) 14 samples the middle value, and 2 spares. Note When approval to variable resistors closer temperature characteristic resistance is desired, two specimens each the highest, the middle and the lowest resistance value shall be submitted for approva! testing and these shall be subjected to the tests Group 0 and VII Routine tests The following shall constitute the routine tests and shall be carried out on each and every resistor : a) Visual examination, b) Continuity, c) Element resistance, and d) Sealing Acceptance tests For the purpose the acceptance the lot, all samples shall be subjected to the tests as given in The following two groups samples Group A and Group B) shall be drawn and the resistors in each group shall be subjected to the tests as speci B ed in the Table 2.

7 IS : 8872 (Part 4ISec 4) 1984 TABLE 2 SCHEDULE OF ACCEPTANCE TESTS 51 s No. Clause Ref in IS : 8872 (Part l)1977 AQL (Percent Defective) Inspection* Level D/ND (1) (2) (3) (4) (5) (6) 9 Group A Dimensions Voltage pro (2 seconds) 8.9 Operating torque 9.2 II ND Contact resistance variation ii) Group B Subgroup B I Solderability s:; ND Subgroup B 2 Resistance to soldering heat Rohustness terminations 9.7 s3 D Endurance (mechanical) (200 cycles) 11.3 Resistance to solvents 11.1 Subgroup B 3 Settability Bump 9.10 s3 D Climatic 10.1 Subgrdup B 4 Endurance (electrical) (168 h) s3 ND D=Destructive, NDNondestructive. Note * Sea IS : Sampling plans and procedures for inspection by attributes for electronic items. 6.2 General Conditions for s See 7 IS : 8872 ( Part 1 > The test schedule and the requirements shall be in accordance with Table 3, TABLE 3 TEST SCHEDULti AND REQUIREMENTS 61 No. Clause Ref Condition Requirements in IS : 8872 ( Part 1 ) 1977 (11 (2) (3) (4) (5) i) 0 Group ( 48 Samples ) a) Visual examination 9.1 The condition, workmanship and finish shall be satisfactory. Marking shall be legible and indelible. ( Continued ) 4

8 IS : 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMENTS Co& SI No. Clause Ref in IS : 8872 (Part 1) 1977 Condition Requirements (1) (21 (3) (4) (5) b) Continuity 8.1 The adjustment device shall be operated steadily and slowly. The change in resistance shall be smooth continuous and unidirectional throughout the actual effective electrical level. c) Dimensions The dimensions the resistors and their terminations shall confirm to the values given in Fig. 1. d) Element resistance 8.2 c) Terminal resistance 8.3 l%is shall be within the selection tolerance f 10 percent. The end resistance at either end the resistor shall not exceed 20 Sz or f 2 percent the total resistance value whichever is greater.. f) Minimum effective resistance and angle ineffective rotation 8.5 The resistance value at angular positions are recorded for information only. Angle ineffective rotation ( from termination a ) This is the angle between the two positions recorded above. Value minimum effective resistance. (from termination n j This is the resistance measured above. value as Angle effective rotation and value minimum effective resistance ( from termination c ) g) Effective resistance and angle effective rotation 8.6 The angle effective rotation shall be : 15 Turns, Min 20 Turns, Max h) Voltage pro V rms for one minute. rhere shall be no breakdown or flashover shall occur. j j Insulation resistance v. rhe value shall be not less than k) Integrity shaft 1) Pull force Resistors shall be mounted on an appropriate mounting fixture with their bodies restrained from movement. A force 23 N shall be applied along the axis the operating shaft, away from the body the resirtor. The force shall be maintained for one minute, Min. Resistors shall be examined for evidence shaft breakage. 2) Perpendicular force iz force 10 N shall be applied in a direction perpendicular to the axis the operating shaft for 1 minute, Min. Resistors shall be examined for evidence shaft breakage. m) Operatiog torque 9.2 The operating torque required The operating torque shall to operate the contact arm at be a maximum 10 mnm. approximately 10, 50 and 90 percent the actual effective electrical travel shall be determined. ( Continued ) 5

9 IS : 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMENTS Contd i!. Teat Clause Ref Condition in IS : 8872 ( Part 1) 1977 Teat Requirements (1) i2) (3) (4) n) Clutch operation (5) The contact arm shall idle against the stop without electrical discontinuity or evidence mechanical damage. The travel the contact arm shall also be capable reversing directon. p) Sealing No bubbling shall occur. q) Contact resistance Number cycles6 The contact resistance variation shall not exceed 3 percent or 352 whichever is greater. ii) First Croup ( 12 Samples) a) Settability The resistor wiper shall be set The settability error shall be at approximately 30, 50 and 75 within * 1 pe:cent percent mechanical rotation. A dc voltage up to 2.5 V shall be applied across the end terminals, and the wiper shall then be adjusted smoothly without abrupt voltage change at each test point. The settability error shall be within the limits specified. b) Solderability c) Robustners terminations As in IS : 8872 (Part l)1977. Tensile : 10 N. In addition, the As in IS : 8872 (Part l)1977. test shall be carried out in the opposite direction, bending : $z bend, to be bent through 0 d) Bump+ 1) Setting stability bumps The change shall not exceed f 1 percent 2) Continuity 8.1 3) Klement resistance 8.2 As in Sl No. (i) (b). The change in the resistance from the initial value shall not exceed f (1 percent ). 4) Visual examination e) Vibration* to Hz, 200 m/s2 There shall be no fracture, loosening parts or other mechanical damage. 1) Setting stability The change shall not exceed f 1 percent. 2) Continuity 8.1 3) Element resistance 8.2 As in Sl No. (i) (b). The change in the resistance from the initial value shall not exceed f ( 1 percent ). *Throughout the test the resistors shall be connected to a suitable monitoring device to determine electrical discontinuity. It is desirable that the detecting equipment shall detect any interruption with a duration 0.1 millisecond or greater. ( Continlled ) 6

10 IS : 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMWTS Conld BE. Clause R in Is : 8872 ( Part 1 )1977 Condition Raqoircmerts (11 (2) (3) (4) (5) 4) Visual examination 9.1 There shall be no fracture, loosening parts or other mechanical damage. f) Shock* km/s 1) Setting stability The change shall not exeeed f 1 percent. 2) Continuity 3) Element resistance As in Sl No. (i) (b). The change in resistance from the initial value shall not exceed i (1 percent Sz ) 4) Visual examination 9.1 There shall be Fno fracture, loosenmg parts or other mechanical damage. g) Acceleration* km/s* 1).Setting stability 2) Continuity 8.1 The change shall.not exceed f 1 percent. As in Sl No. (i) (b). 3) Element resistance 4) Visual examination The change in resistance from the initial value shall not exceed i ( 1 percent ). There shall be no fracture, loosening parts or other mechanical damage. h) Rapid ehange temperature ) Setting stability The change shall not exceed at 1 percent. 2) Continuity 8.1 As in Sl No. (i) (b). 3) Element resistance 8.2 The change in resistance from the initial value shall not exceed f 1.5 percent. 4) Visual examination 9.1 There shall be no fracture, loosening parts or other mechanical damage. j) Climatic tests 10 1) Dry heat ) Damp heat ( accelerated ) ) Cold test ) Operating torque 9.1 5) Low air pressure At + loo C, 16 h One cycle At 55W, 2 h 2 kpa The voltage pro test shall be done at 350 V rms. The value shall not exceed 1.5 times the maximum value specifiedin Sl NO. (i) (m). There shall be no breakdown or flashover *Throughout the test the resistors shall be connected to a suitable monitoring device to determine electrical discontinuity. It is desirable that the detecting equipment shall detect any interruption with a duration O1 millisecond or greater. ( Confinued ) 7

11 IS : 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMENTS Con&f SI No. Clause Ref Condition in IS :8872 ( Part 1 ) 1977 Requirements (1) (2) 6) Damp heat ( accelerated ) remaining cycles (3) (4) 10.l.G 5 Cycles (5) i) Working test _ The voltage to be applied shall There thall be no breakdown be the rated voltage. or flashover. Final Meamrcmentr : 1) Visual examination 2) Continuity 3) Element resistance There shall be no corrosion fracture, loosening parts or other mechanical damage. Marking shall be legible and indelible. As in Sl No. (i) (b). The change in resistance from the initial value shall not cxteed f 2 percent. 4) Insulation Resistance ) Voltage pro 8.9 The value shall be not less than 1OOMP. There shall be no breakdown or flashover. iii) Second Grouj (6 Samples) a) Damp heat (long term) 10.2 A dc voltage 20 f 2 V shall be apphed to half the specimens between termination b and the external metal parts ( termination being positive ) and no voltage shall be applied for the other half specimens. _ i) Working test 1) Visual examination 2) Elcrnent resistance The voltage to be applied shall be the rated voltage There shall be no breakdown or flashover. There shall be no corrosion fracture, loosening parts or other mechanical damage. Marking shall be legible and indelible. The change in resistance from the initial value shall not exceed f 2 percent. 3) Insulation resistance , Voltage pro 8.9 5) Solderability The value shall be not less than 100 M Q. There shall be no breakdown or flashover. As in Sl No. (ii) (b). iv) l hird Groub ( 6 Samfiles) a) Bndurancc ( mechanical ) cycles. 1 cycle in 2.0 += O5 minutes. The specimens shall be mounted by their normal mounting means on a I.6 mm thick glass epoxy laminate. The specimens shall be ganged in pairs and each pair shall be connected in series so that a nominally constant current flows through the resistors, irrespective the contact arm position during the turning the lead screw actuator. ( Continued) 8

12 IS: 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMENTS Conrd Sl No. Clause Ref Coadition in IS : 8872 ( Part 1 ) 1977 Requirementm (2) (3) (4) (5) 1 j Visual examination 9.1 There shall be no fracture, loosening parts or other mechanical damage. 2) Continuity 8.1 As in Sl No. (i) (b). 3) Element resistance 8.2 The change in resistance from the initial value shall not exceed f 2 percent. v) Fourth Group ( 6 Samples ) a) Endurance ( electrical ) 1) Vilual cxaminatlon At + 7o c. The specimens shall he preconditioned at the test temperature for a period 8 hours before the start the test. The specimens shall be mounted hy their normal means on a 1.6 mm thick glass epoxy laminate. The specimens shall be so arranged that the temperatnre any one specimen shall not appreciably influence the temperature any other specimen, There shall he no undue draft over the resistors. There shall be no fracture, or any other mechanical damage. Marking shall be legible and indelible. 2) Continuity 8.1 3) Element resistanee 8.2 4) Insulation resistance 8.10 As in Sl No. (i) (b). The change in resistance from the initial value shall not exceed f 2 percent. As in Sl No. (i) (j) 5) Voltage pro 8.9 There shall be no breakdown or flashover. 6) Setting stahility 7) Operating torque 9.2 h) Flammability 11.2 The change shall not exceed f 1 percent. The value shall not exceed 1 5 times the maximum value specified in Sl. No. (i) (m). As in IS : 8872 (Part I)1977. vi) Fayth Group ( 3 Samples ) a) Mould growth 10.4 As in IS : 8872 (Part 1) vii) Sixtlr &or@ ( 3 SampleJ 1 a) Resistance to solvents 11.1 As in IS : 8872 (Part l)1977. h) Resistance to soldering heat ) Visual examination 9.1 There shall be no fracture, loosening parts or other mechanical deterioration. 2) Element resistance 8.2 The change in resistance from the initial value shall not excecd f 1 percent + O50) ( Continued) 9

13 IS: 8872 ( Part 4/Set 4 ) 1984 TABLE 3 TEST SCHEDULE AND REQUIREMENTS Conrd SI No. C1aosc Rcf in IS : 8872 ( Part 1 ) 1977 Condition Requirements f.1) (2) viii) Seventh Groufi ( 6 Sampfcs ) a) Temperature characteristic resistance (3) 8.11 (4) (5) Drying as per procedure II The value shall be f 100 ppm/ C or 250 ppm/ C as applicable. b) Salt mist ) Visual examination 9.1 There shall bc no corrosion, loosening parts or other mechanical deterioration. Marking shall be legible and indelible. 2) Element resistance 3) Insulation resistance 4) Operating torqoe 8.2 As in Sl No. (i) (c) As in Sl No. (i) (j) s in Sl No. (i) (m). ti) Spares ( 6 Samples) 10 Printed t.dcihi Priotm. lhlbi. India