1、BRITISH STANDARD BS 3238-2: 1964 Graphical symbols forcomponents of servo-mechanisms Part 2: General Servo-mechanismsBS 3238-2:1964 This British Standard, having been approved by the InstrumentIndustry Standards Committee and endorsed by the Chairman ofthe Engineering Divisional Council, was publish
2、edunder the authority ofthe GeneralCouncil on 28February1964 BSI 03-2000 The following BSI references relate to the work on this standard: Committee references INE/1/2 andINE/1/2/2 Draft for comment AA(INE) 9313 ISBN 0 580 34405 3 Co-operating organizations The Instrument Industry Standards Committe
3、e, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Scientific Workers British Clock and Watch Manufacturers Association British Electrical and Allied Manufact
4、urers Association* British Industrial Measuring and Control Apparatus Manufacturers Association* British Iron and Steel Federation* British Nautical Instrument Trade Association British Railways Board British Scientific Instrument Research Association* Council of British Manufacturers of Petroleum E
5、quipment* Electrical Research Association Electricity Council, The Generating Board and the Area Boards in England and Wales Electronic Engineering Association* Engineering Equipment Users Association* Gauge and Tool Makers Association Institute of Physics and the Physical Society Institution of Che
6、mical Engineers* Institution of Electrical Engineers* Institution of Heating and Ventilating Engineers Institution of Mechanical Engineers Iron and Steel Institute Meteorological Office Ministry of Health Ministry of Housing and Local Government National Coal Board National Physical Laboratory (D.S.
7、I.R.)* Oil Companies Materials Association* Scientific Instrument Manufacturers Association* Society of Instrument Technology* War Office* Water-tube Boilermakers Association* The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together w
8、ith the following, were directly represented on the committees entrusted with the preparation of this standard: Admiralty Air Ministry Institution of Gas Engineers Ministry of Aviation Society of British Aircraft Constructors Ltd. United Kingdom Atomic Energy Authority Amendments issued since public
9、ation Amd. No. Date CommentsBS 3238-2:1964 BSI 03-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii Appendix Examples of the application of standard symbols 18 Figure 1 Position control servo block diagram 18 Figure 2 Gyro repeater servo block diagram 19BS 3238-2:1964 ii
10、 BSI 03-2000 Foreword This standard makes reference to the following British Standards: BS 108, Graphical symbols for general electrical purposes. BS 530, Graphical symbols for telecommunications. BS 1523, Glossary of terms used in automatic controlling and regulating systems Section 5: Components o
11、f servo-mechanisms. BS 2917, Graphical symbols for use in diagrams for fluid power transmission and control systems. BS 3238, Graphical symbols for components of servo-mechanisms Part1:Transductors and magnetic amplifiers. This British Standard tabulates graphical symbols for general servo-mechanism
12、s and is the second section of a publication prepared to serve as a companion standard to BS1523, “Glossary of terms used in automatic controlling and regulating systems”, Section5:1954, “Components of servo-mechanisms”. Thefirst section (BS3238-1:1960) has already been published and deals with grap
13、hical symbols for transductors and magnetic amplifiers. Not all the general servo-mechanism terms in BS1523 are considered to need graphical symbols, for various reasons; e.g. the item defined can often be most suitably shown by a composite diagram built up from basic components which in some cases
14、are not specified due to the wideness of the definition. While compiling this standard several other standards already published on graphical symbols for particular purposes, e.g. for the electrical industry, the machine tools industry and the aircraft industry, have been kept closely in mind.The ob
15、ject of this standard is to develop standard symbols which allow the functioning and interconnections of general servo-mechanisms to be indicated ona single diagram even though the mechanisms may be, and usually are, a combination of electrical, mechanical, and hydraulic or pneumatic devices. It is
16、this type of diagram that is required by the servo-mechanism manufacturer and user. An Appendix is included by way of example to illustrate the use of the symbols in diagrams of relatively simple servo-mechanisms. As far as is known no previous attempt has been made to standardize the graphical symb
17、ols for a large number of the components mentioned in BS1523, and special consideration has had to be given to the degree of detail which wouldbe desired by users. In this respect it is felt that two main requirements exist, firstly, graphical symbols for use in diagrams which show all the interconn
18、ections of the servo-mechanism and convey the principle of functioning of the mechanism in reasonable detail; secondly, a very much simpler type of symbol for use in block diagrams which are often required to facilitate explanation of the system. While it is not considered that the size of the symbo
19、ls should be rigidly specified, for the guidance of users and to assist in the production of stencils should these be required, it is mentioned that the scale used for the symbols in the body of this draft is that recommended for general use in diagrams. In general the presentation of the symbols de
20、tailed in this standard should be sothat the “cause to effect” is shown from left to right. However, different arrangements of symbols may be used where this principle cannot be followed, asfor example in feedback loops, the standard symbols may then be turned in anydirection to obtain the best pres
21、entation. Where it is desired to show that certain items of a servo-mechanism system are grouped together either functionally or physically the symbols for these items may be enclosed within a chain dotted boundary.BS 3238-2:1964 BSI 03-2000 iii A British Standard does not purport to include all the
22、 necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, p
23、ages1to 19 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS 3238-2:1964 BSI 03-2000 1 Item number and description Number in BS 1523 Section5 Further descr
24、iption and Notes Symbol 1 General symbol Shafts The black and white portions are equal in length and should be approximately four times the diameter of the shaft. NOTE AIn block diagrams where it is desired to show multiple drives from a single shaft they may be represented by means of tee-junctions
25、. (SeeAppendix, Figure 1). NOTE BThere is no significance in the position of any component either on a shaft or receiving a shaft in relation to the shaft illustration. 2 Direction of cause to effect (here,leftto right). 3 Rotation and direction of rotation 4 The symbol for indicating limited rotati
26、on is a constant length arc, the limits being defined by writing in the angle, when known. 5 Translatory motion Where it is important to specify the limits of this motion they shall be defined by writing them in an appropriate position along-side the symbol. 6 Shafts crossing, but not connected 7 Co
27、nnected shafts. The number of sectors inside the circle shall be equal to the number of shafts coupled to the gear box. Numbers in the sectors indicate the speed ratio between two shafts.BS 3238-2:1964 2 BSI 03-2000 Item number and description Number in BS 1523 Section5 Further description and Notes
28、 Symbol 8 General symbol. NOTETo improve the clarity of composite diagrams, pipes may be drawn thicker than electrical conductors. Pipes 9 Where necessary, to distinguish between pipes and electrical conductors to a single piece of equipment, where a pipe is attached to any mechanism a “nipple” may
29、be shown. As an example a pipe is shown here attached to a mechanism Xsignified by the square. 10 Pipes crossing a. Pipes NOTEThis is an additional method of differentiating between pipes and electrical conductors. b. Shafts c. Electrical conductors 11 Connected pipes NOTEThe connector dot should be
30、 approximately five times the width of the associated lines. 12 General symbol. Electrical conductors 13 Electrical conductors crossing, but not connected.BS 3238-2:1964 BSI 03-2000 3 Item number and description Number in BS1523 Section 5 Further description and Notes Symbol 14 Connected electrical
31、conductors Electrical conductors (continued) 15 5103-5 and5301 General symbol. Mechanical differentials NOTEPlus or minus signs in the sectors opposite the input shafts may be used to indicate the contribution of each of these shafts to the input: positive rotation being clockwise when viewed by an
32、observer looking towards the gear. A cage may be indicated thus. 16 5103 5301 Differential gear or summing gear. The arcs indicating rotation need be included only if desired. 17 5104 and 5105 Rack type differential or differential lever. If more detail isdesired the particular symbols given below m
33、ay be used. 18 5104 Rack type differential 19 5105 Differential lever.BS 3238-2:1964 4 BSI 03-2000 Item number and description Number in BS1523 Section 5 Further description and Notes Symbol 20 General symbol. Electrical pick-offs The nature of the input, i.e.whether mechanical, hydraulic, or pneuma
34、tic, etc. is tobe indicated as appropriate atthe left side of square. Variations of the short diagonal line are intended to represent the basic functions of the pick-offs, such variations being as follows: Potentiometer pick-off Inductive pick-off Capacitive pick-off Temperature dependence t Light o
35、r other radiant energy pick-off NOTERadioactive input may be shown by the inclusion above the arrows of or as appropriate. 21 5108 Potentiometer pick-off. This, andthe following symbols are forcircuit diagrams, where moredetail is required. NOTEThe broken line indicates that there is a mechanical co
36、upling between mechanical and electrical systems but not an electrical connection. 22 5106 Inductive pick-off. Example I. with reversible phase output. Example II. simple pick-off with irreversible phase output. NOTEThe broken line indicates that there is a mechanical coupling between mechanical and
37、 electrical systems but not an electrical connection.BS 3238-2:1964 BSI 03-2000 5 Item number and description Number in BS 1523 Section 5 Further description and Notes Symbol 23 5107 Contact pick-off. Electrical pick-offs (continued) The contact arrangement will vary with the type of pick-off, and i
38、s to be drawn according to BS 108 a . This is given as an example. NOTEThe broken line indicates that thereis a mechanical coupling between mechanical and electrical systems but not anelectrical connection. 24 5110 etc. Generic symbol Synchros The appropriate letter for the particular synchro being
39、symbolized shall be inserted inside the inner circle. The letters to be used, according to the function of the synchro, are as follows: First letter Function C T R Control Torque Resolver Succeeding letters Function D R T X B Differential Receiver Transformer Transmitter Rotatable stator winding In
40、the symbol the inner circle represents the rotor and the outer circle the stator or, in certain instances, a rotatable outer winding. 25 Typical example illustrating electrical connectors to a torque transmitter. NOTETerminal markings, which should correspond with those appearing on the component, m
41、ay be added if required. 26 Method of showing shaft. NOTEThe general orientation of the shaftshould suit terminal arrangements. 27 Method of showing clamped shaft. NOTEThe general orientation of the shaft should suit terminal arrangements. a BS 108, “Graphical symbols for general electrical purposes
42、”.BS 3238-2:1964 6 BSI 03-2000 Item number and description Number in BS 1523 Section 5 Further description and Notes Symbol 28 Method of showing two shafts. Synchros (continued) NOTEThe general orientation of the shaftshould suit terminal arrangements. 29 5201 Generic symbol with input and output co
43、nnections as appropriate to the type of amplifier. (Seeexamples below.) NOTEThe symbol points in the direction oftransmission. Variations of this symbol to illustrate specific types of amplifier may be made, for instance a summing amplifier maybe shown thus: Amplifiers 30 5247 The symbol given is fo
44、r the particular form of amplifier defined in BS1523, term No. 5247. Hydraulic amplifiers 31 5248 The symbol given is for the particular form of relay defined inBS1523, term No. 5248. Pneumatic amplifiers 32 5202 The vertical shaft comes from the local power source. Torque amplifiers 33 5203 to 5206
45、 Symbol for single line block diagrams. NOTEAppropriate symbols from BS 530 amay be used to denote the nature or functionof the amplifier. Electrical amplifiers Symbol for circuit diagrams. (Example) where internal details ofthe amplifier are not required. (Theexample shown is one type ofpush-pull a
46、mplifier.) If internal details of the amplifier are required use BS 530 a a BS 530, “Graphical symbols for telecommunications”.BS 3238-2:1964 BSI 03-2000 7 Item number and description Number in BS 1523 Section 5 Further description and Notes Symbol 34 5208 to 5210 General symbol for block diagrams.
47、Rotary amplifiers 35 5209 and 5210 Metadyne or amplidyne symbol for circuit diagrams. The shaft and drive would be omitted unless it were desired to show details of this feature. 36 5223 to 5243 The symbol shown is a general symbol for a block diagram reference should be made to BS3238-1 for additio
48、nal information on magnetic amplifiersymbols. Magnetic amplifiers 37 5244 to 5246 Symbol for block diagrams (example). Pumps The type of pump should be indicated within the basic symbolby the appropriate lettersas listedbelow: PF Fixed displacement PK Kinetic, centrifugal PV Variable displacement 38
49、 5244 to 5246 Means of control. Additionally in the pump symbols the means of control, may as here, be shown by inserting appropriate letters inside the rectangle as follows: ELECElectrical MECHMechanical HYDHydraulic PNEUPneumatic MANManualBS 3238-2:1964 8 BSI 03-2000 Item number and description Number in BS 1523 Section 5 Further description and Notes Symbol 39 The following symbols are for circuit diagrams and show how to indicate different means of control. Variable displacement pump withelectrical means of control reversible flo
