1、BRITISH STANDARD BS 5786-1: 1979 IEC 418-1: 1974 Incorporating Amendment No. 1 Variable capacitors Part 1: Methods of test UDC 621.318.43BS5786-1:1979 This British Standard, having been prepared under the directionof the Electronic Components Committee, was published under the authority ofthe Execut
2、ive Board and comesinto effect on 31October1979 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference ECL/4 Draft for comment 79/21700 DC ISBN 0 580 10933 X Cooperating organizations The Electronic Components Standards Committee, under whose direction this
3、 British Standard was prepared, consists of representatives from the following scientific and industrial organizations: British Electrical and Allied Manufacturers Association Electricity Supply Industry in England and Wales* Electronic Components Industry Federation* Electronic Engineering Associat
4、ion* Institution of Electronic and Radio Engineers National Supervising Inspectorate* Post Office* Society of British Aerospace Companies* Telecommunication Engineering and Manufacturing Association (TEMA) The organizations marked with an asterisk in the above list, together with the following, were
5、 directly represented on the committee entrusted with the preparation of this British Standard: British Broadcasting Corporation Electrical Research Association Amendments issued since publication Amd. No. Date of issue Comments 4030 September 1982 Indicated by a sideline in the marginBS5786-1:1979
6、BSI 01-2000 i Contents Page Cooperating organizations Inside front cover National foreword ii Section 1. General 1 Scope 1 2 Object 1 3 Terminology 1 Section 2. General requirements for tests 4 Test conditions 5 Section 3. Methods of test 5 Visual examination 5 6 Dimensions and effective angle of ro
7、tation 6 7 Capacitance 6 8 Blacklash 8 9 Tangent of the loss angle 8 10 Insulation resistance 8 11 Voltage proof 9 12 Rotor contact resistance 9 13 Temperature coefficient 9 14 Capacitance drift 10 15 Operating torque 11 16 Locking 11 17 Locking torque proof 11 18 End stop torque 11 19 Thrust and pu
8、ll (axial) 12 20 Side thrust 12 21 Robustness of terminations 13 22 Rapid change of temperature 13 23 Soldering 13 24 Impact 14 25 Vibration 15 26 Climatic sequence 15 27 Damp heat (steady state) 16 28 Corrosion 17 29 Endurance 17 30 Sealing (normal conditioning) 18 31 Sealing (extended conditioning
9、) 18 32 Capacitance drift after adjustment 19 Figure 1 Illustration of capacitance measuring positions 7 Publications referred to Inside back coverBS5786-1:1979 ii BSI 01-2000 National foreword This British Standard has been prepared under the direction of the Electronic Components Standards Committ
10、ee. It is identical with International Electrotechnical Commission Publication IEC418-1:1974 “Variable capacitors. Part 1. Terms and methods of test”. Amendment No. 1 (1976) to IEC418-1:1974 has been incorporated in the text of this standard. Terminology and conventions. The text of the Internationa
11、l Standard has been approved as suitable for publication, without deviation, as a British Standard. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. Wherever the word “recommendation” appears, referring t
12、o this standard, it should be read as “British Standard”. Cross-references International Standard Corresponding British Standard ISO 3:1973 BS 2045:1965 Preferred numbers (Technically equivalent) IEC 68-1:1968 BS 2011 Basic environmental testing procedures Part 1.1:1977 General (Identical) IEC 68-2-
13、1:1974 BS 2011 Basic environmental testing procedures Part 2.1A:1977 Test A. Cold (Identical) IEC 68-2-2:1974 BS 2011 Basic environmental testing procedures Part 2.1B:1977 Test B. Dry heat (Identical) IEC 68-2-3:1969 BS 2011 Basic environmental testing procedures Part 2.1Ca:1977 Test Ca. Damp heat,
14、steady state (Identical) IEC 68-2-4:1960 BS 2011 Basic environmental testing procedures Part 2.1Da:1977 Test Da. Accelerated damp heat (Identical) IEC 68-2-6:1970 BS 2011 Basic environmental testing procedures Part 2.1Fc:1977 Test Fc. Vibration (sinusoidal) (Identical) IEC 68-2-13:1966 BS 2011 Basic
15、 environmental testing procedures Part 2.1M:1977 Test M. Low air pressure (Identical) IEC 68-2-14:1974 BS 2011 Basic environmental testing procedures Part 2.1N:1977 Test N. Change of temperature (Identical) IEC 68-2-17:1968 BS 2011 Basic environmental testing procedures Part 2.1Q:1977 Test Q. Sealin
16、g (Identical) IEC 68-2-20:1968 b) their ability to withstand specified conditions of mechanical shock such as are to be expected under transit or operational conditions; c) their ability to withstand the rigours of normal assembly processes (e.g.soldering) attendant on their incorporation in equipme
17、nts, without detriment toa) andb) above. Some tests in this recommendation are accelerated tests or tests under conditions which may represent or even exceed the most severe conditions of use. Such tests establish arbitrary standards of quality and they cannot be held to give positive information of
18、 any performance beyond or outside the test periods and test conditions. Where the required operating conditions differ materially from the test conditions specified herein, reference should be made to the manufacturers regarding the suitability of a component for a particular purpose. In general, l
19、onger periods of life for a given performance limit may be expected where the environment or loading imposes a less severe stress on the component. The tests described in this recommendation are applicable to each section of multi-section capacitors, unless otherwise specified in the relevant specif
20、ication. 3 Terminology For the purposes of this recommendation the following definitions shall apply: 3.1 variable capacitor a capacitor which is designed to enable the capacitance to be varied continuously over its complete range 3.2 differential capacitor a capacitor comprising two isolated stator
21、s which are operated with one rotor, arranged so that as the capacitance between the rotor and one stator increases, the capacitance between the rotor and the other stator decreases, but the sum of the two capacitance values remains substantially constant at all settings 3.3 split stator capacitor a
22、 capacitor comprising two isolated stators which function in series with a common rotor 3.4 section a stator and its corresponding rotor 3.5 multi-section capacitor a capacitor which has several sections, the capacitance values of which are varied simultaneously by a common actuating deviceBS5786-1:
23、1979 2 BSI 01-2000 3.6 reference section that section to which other sections are matched 3.7 matching section a section matched to a reference section 3.8 Type Is determined by the function and is governed by the ability of the capacitor to withstand various severities of mechanical endurance (see
24、Sub-clause29.1). 3.8.1 type A a capacitor which is intended to be operated frequently throughout its life. When used for tuning purposes, this capacitor may be provided with a control spindle to which a knob or drive may be fitted 3.8.2 type B a capacitor used for trimming or for other similar purpo
25、ses, where the amount and duration of movement of the rotatable electrode is considerably less than that of Type A 3.8.3 type C a capacitor used specifically as a pre-set capacitor where a comparatively small number of movements are required during its life 3.9 Style The method of varying the capaci
26、tance. 3.9.1 style 1 concentric an air dielectric capacitor where the capacitance can be varied by the axial movement of a rotor in a stator 3.9.2 style 2 vane a capacitor where the capacitance can be varied by rotating the rotor vanes between the stator vanes 3.9.3 style 3 tubular a solid dielectri
27、c capacitor where the capacitance can be varied by the axial movement of an electrode within a tube 3.9.4 style 4 compression a capacitor where the capacitance can be varied by compressing a stack of electrode and dielectric layers 3.9.5 style 5 disk a solid dielectric capacitor where the capacitanc
28、e can be varied by rotating a metal or metallized diskBS5786-1:1979 BSI 01-2000 3 3.10 descriptive code the description of the type (function), dielectric, style and application of a capacitor may be in the form of a four character code as follows: Example: For a pre-set capacitor, solid dielectric,
29、 tubular style, for professional application, the descriptive code is C231. 3.11 maximum capacitance the value which is obtained with the actuating device adjusted in the manner prescribed in the relevant specification 3.12 minimum capacitance the value which is obtained with the actuating device ad
30、justed in the manner prescribed in the relevant specification 3.13 capacitance swing the difference between maximum and minimum capacitance values 3.14 capacitance law the relationship between capacitance and the position of the actuating device 3.15 effective angle of rotation the angle (or number
31、of turns) through which the rotor moves between the positions of maximum and minimum capacitance 3.16 total angle of rotation the angle (or number of turns) through which the rotor moves between the end stops. If there are no end stops, then the total angle of rotation is the effective angle of rota
32、tion 3.17 nominal angle of rotation the angle used for determining the measuring points when capacitance law measurements are made 3.18 backlash the difference in capacitance (expressed as a ratio) obtained at a specified measuring angle when the actuating device is moved to approach this measuring
33、angle from a clockwise and then from an anti-clockwise direction Descriptive code Type (function) C 2 3 1 C A = Tuning capacitor B = Trimmer capacitor C = Pre-set capacitor Dielectric 2 1 = Air 2 = Solid Style 3 1 = Concentric 2 = Value 3 = Tubular 4 = Compression 5 = Disk Application 1 1 = Grade 1
34、professional 2 = Grade 2 domestic BS5786-1:1979 4 BSI 01-2000 3.19 apparent power the maximum VA rating at which the capacitor can be used in relation to temperature rise, in terms of frequency, current and voltage 3.20 lower category temperature the lowest ambient temperature at which the capacitor
35、 is designed to operate continuously 3.21 upper category temperature the highest ambient temperature at which the capacitor is designed to operate continuously 3.22 category temperature range the range of ambient temperatures for which the capacitor is designed to operate continuously 3.23 capacitan
36、ce drift after adjustment the change in capacitance (expressed as a ratio) obtained in a stated time after the actuating device has been rotated at a specified speed to a stated capacitance 3.24 nominal capacitance those values which are indicated upon the capacitor or the package. These will be def
37、ined in the relevant specification and will comprise one or more of the following: Capacitance swing (nominal), Maximum capacitance (nominal), Minimum capacitance (nominal). 3.25 rated voltage the maximum peak voltage which may be applied continuously to the terminals of a capacitor at any temperatu
38、re in the category temperature range NOTERated voltages shall be selected from the R5 series given in ISO/R3. Where intermediate values are required, these shall be chosen from the R10 series. 3.26 rotor contact resistance the resistance between the rotor contact terminal and the rotor shaft 3.27 ty
39、pe tests the complete series of tests to be carried out on a number of specimens which are representative of the type, with the object of determining whether a particular manufacturer can be considered to be able to produce products meeting the specification 3.28 type approval the decision by the pr
40、oper authority (the user himself or his nominee) that a particular manufacturer can be considered to be able to produce in reasonable quantities the products meeting the specification 3.29 acceptance tests tests carried out to determine the acceptability of a consignment on the basis of an agreement
41、 between user and manufacturer. The agreement shall cover: a) the sample size; b) the selection of tests;BS5786-1:1979 BSI 01-2000 5 c) the extent to which the test specimens shall conform to the requirements for the selected tests of the specification. NOTEWhen differing test results are obtained b
42、y user and manufacturer, the IEC standard methods shall be used for referee purposes. 3.30 factory tests those tests carried out by the manufacturer to verify that his product meets the specification Section 2. General requirements for tests 4 Test conditions The method specified initially for any t
43、est or measurement shall, unless otherwise specified, be used for all subsequent applications of that test or measurement. For measurements of capacitance, the measuring method shall be such that the error does not exceed: a) 10% of the rated capacitance tolerance for absolute capacitance measuremen
44、ts; b) 10% of the specified maximum capacitance change for measurements of capacitance change. Where a test requires an application of torque, the method used shall be such as to ensure an accuracy of 10%. 4.1 Standard atmospheric conditions for testing Measurements on capacitors shall, unless other
45、wise specified, be carried out under standard atmospheric conditions for testing as specified in IEC Publication68-1, Basic Environmental Testing Procedures, Part1, General, within the times stated. During these measurements, the test samples shall be protected from draughts and direct sun-rays. Whe
46、re measurements are required during conditioning periods, the same requirement shall apply unless otherwise specified. 4.2 Methods of mounting If the method of mounting is important, the relevant specification shall prescribe which of the following methods of mounting shall be used: Method A. The ca
47、pacitor shall be rigidly mounted by the means provided, without causing abnormal stressing. Method B. The capacitor shall be rigidly mounted by the means provided and without causing abnormal stressing, on a flat machined metal plate approximately3mm thick and at least25mm larger than the linear dim
48、ensions of the mounting face of the capacitor. Method C. The capacitor shall be rigidly mounted by the means provided and without causing abnormal stressing, on a metal plate larger than the projection of the capacitor. Method D. Any other method as described in the relevant specification. NOTECare
49、shall be taken in the relevant specification to describe fully the mounting arrangements since these may affect measurements of minimum capacitance and temperature coefficient. 4.3 Test samples When the tests described in this document are specified in a schedule of type tests, the number of specimens required shall be prescribed in the relevant specification. Capacitors which have been subjected to type tests shall not be used in equipment or returned to bulk supply. 4.4 Schedule for type tests Type t
