Registration of schematic diagrams of guests. Overview of conventional graphic symbols used in electrical circuits
STATE STANDARDS OF THE UNION OF THE SSR
UNIFIED SYSTEM OF DESIGN DOCUMENTATION
RULES FOR THE IMPLEMENTATION OF SCHEMES
GOST 2.702-75
USSR STATE COMMITTEE ON STANDARDS
Moscow
STATE STANDARD OF THE UNION OF THE SSR
By the Decree of the State Committee of Standards of the Council of Ministers of the USSR dated September 7, 1975 No. 2584, the deadline for the introduction is setfrom 01.07.77
This standard applies to electrical circuits of products in all industries, as well as electrical circuits of power facilities and establishes the rules for their implementation manually or automatically. Types and types of schemes and general requirements for their implementation - according to GOST 2.701-84. Alphanumeric designations in electrical circuits - according to GOST 2.710-81. The standard complies with ST SEV 1188-78 in terms of Sec. 2 - 4, 6 - 9 (see reference appendix).
1. RULES FOR THE IMPLEMENTATION OF STRUCTURAL SCHEMES
1.1. The block diagram depicts all the main functional parts of the product (elements, devices and functional groups) and the main relationships between them. 1.2. Functional parts in the diagram are depicted in the form of a rectangle or conventional graphic symbols. 1.3. The graphic construction of the scheme should give the most visual representation of the sequence of interaction of functional parts in the product. On the lines of relationships, it is recommended that arrows indicate the direction of the course of processes occurring in the product. 1.4. The diagram should indicate the names of each functional part of the product, if a rectangle is used to designate it. It is allowed to indicate on the diagram the type of element (device) and (or) the designation of the document (main design document, state standard, technical specifications), on the basis of which this element (device) was applied. When depicting functional parts in the form of rectangles, it is recommended to enter names, types and designations inside the rectangles. 1.5. With a large number of functional parts, instead of names, types and designations, it is allowed to put serial numbers to the right of the image or above it, as a rule, from top to bottom in the direction from left to right. In this case, the names, types and designations are indicated in the table placed on the field of the scheme. 1.6. It is allowed to place explanatory inscriptions, diagrams or tables on the diagram that determine the sequence of processes in time, as well as indicate the parameters at characteristic points (values of currents, voltages, shapes and sizes of pulses, mathematical dependencies, etc.).2. RULES FOR THE PERFORMANCE OF FUNCTIONAL SCHEMES
2.1. The functional diagram depicts the functional parts of the product (elements, devices and functional groups) involved in the process illustrated by the diagram, and the links between these parts. 2.2. Functional parts and connections between them are depicted in the diagram in the form of conventional graphic symbols established in the standards of the Unified Design Documentation System. Separate functional parts are allowed to be depicted in the form of rectangles. 2.3. The graphic construction of the scheme should give the most visual representation of the sequence of processes illustrated by the scheme. 2.4. When performing a functional diagram, it is allowed to use the provisions specified in paragraphs. 3.6 - 3.15 and 3.24. 2.5. The diagram should indicate: for each functional group - the designation assigned to it on the schematic diagram, and (or) its name; if the functional group is shown as a conventional graphic designation, then its name is not indicated; for each device shown as a rectangle - the reference designation assigned to it on the circuit diagram, its name and type and (or) the designation of the document (main design document, state standard, technical specifications), on the basis of which this device is used; for each device depicted in the form of a conventional graphic designation - the reference designation assigned to it on the schematic diagram, its type and (or) document designation; for each element - a reference designation assigned to it on the schematic diagram, and (or) its type. The designation of the document on the basis of which the device was used, and the type of element may not be indicated. Names, types and designations are recommended to be entered in rectangles. 2.6. It is recommended to indicate the technical characteristics of the functional parts on the diagram (next to the graphic symbols or in the free field of the diagram). 2.7. Explanatory inscriptions, diagrams or tables are placed on the diagram that determine the sequence of processes in time, and also indicate the parameters at characteristic points (values of currents, voltages, shapes and sizes of pulses, mathematical dependencies, etc.).3. RULES FOR THE IMPLEMENTATION OF PRINCIPAL DIAGRAM
3.1. The schematic diagram depicts all electrical elements or devices necessary for the implementation and control of the specified electrical processes in the product, all electrical connections between them, as well as electrical elements (connectors, clamps, etc.) that end the input and output circuits. (Revised edition, Rev. No. 2). 3.2. It is allowed to depict connecting and mounting elements installed in the product for design reasons on the diagram. 3.3. Schemes are performed for products that are in the off position. In technically justified cases, it is allowed to depict individual elements of the circuit in the selected working position with an indication of the mode for which these elements are depicted on the field of the circuit. 3.4. Elements and devices, the graphic symbols of which are established in the standards of the Unified Design Documentation System, are depicted on the diagram in the form of these graphic symbols. (New edition, Rev. No. 3). 3.5. Elements or devices used in the product in part may be depicted in the diagram incompletely, limited to the image of only the parts or elements used. (New edition, Rev. No. 3). 3.6. Elements and devices are depicted on the diagrams in a combined or spaced way. 3.7. With the combined method, the components of elements or devices are depicted in the diagram in close proximity to each other. 3.8. With the exploded method, the components of elements and devices or individual elements of devices are depicted on the diagram in different places so that the individual circuits of the product are most clearly depicted. It is allowed to depict all and individual elements or devices in a spaced way. When executing schemes, it is recommended to use the line method. In this case, the conventional graphic designations of the elements or their components included in one chain are depicted sequentially one after another in a straight line, and individual chains are side by side, forming parallel (horizontal or vertical) lines. When executing the scheme in a line way, it is allowed to number the lines with Arabic numerals (Fig. 1).
Crap. 1. (New edition, Rev. No. 3). 3.9. When depicting elements or devices in a spaced way, it is allowed to place conditional graphic symbols of elements or devices made in a combined way on the free field of the diagram. At the same time, the elements or devices used in the product in part are depicted in full with an indication of the used and unused parts or elements (for example, all contacts of a multi-contact relay). The conclusions (contacts) of unused elements (parts) are shown shorter than the conclusions (contacts) of the used elements (parts) (Fig. 2).
A- multi-line image; b- single line image.
Crap. 3. (New edition, Rev. No. 3). 3.14. When depicting various functional circuits on the same diagram, it is allowed to distinguish them by line thickness. In one scheme, it is recommended to use no more than three line sizes in thickness. If necessary, appropriate explanations are placed on the field of the scheme. 3.15. To simplify the circuit, it is allowed to merge several electrically unconnected connection lines into a group connection line, but when approaching contacts (elements), each connection line is depicted as a separate line. When merging communication lines, each line is marked at the merging point, and, if necessary, at both ends with symbols (numbers, letters, or a combination of letters and numbers) or symbols adopted for electrical circuits (see clause 3.13). Line designations are affixed in accordance with the requirements given in GOST 2.751-73. Electrical communication lines merged into a group communication line, as a rule, should not have branchings, i.e. each conditional number must occur twice on the group communication line. If branching is necessary, their number is indicated after the serial number of the line through a fractional line (Fig. 3a).
3.16. Each element and (or) device that has an independent circuit diagram and is considered as an element included in the product and depicted in the diagram must have a designation (reference designation) in accordance with GOST 2.710-81. Devices that do not have independent circuit diagrams and functional groups are recommended to be assigned designations in accordance with GOST 2.710-81. 3.15, 3.16. (Revised edition, Rev. No. 2). 3.17. Positional designations for elements (devices) should be assigned within the product (installation). 3.18. Sequential numbers for elements (devices) should be assigned, starting from one, within a group of elements (devices), which are assigned the same letter designation in the diagram, for example, R 1 , R 2 , R 3 etc., C 1 , C 2 , C3 etc. 3.19. Serial numbers must be assigned in accordance with the sequence of elements or devices on the diagram from top to bottom in the direction from left to right. If necessary, it is allowed to change the sequence of assigning serial numbers, depending on the placement of elements in the product, the direction of the signals, or the functional sequence of the process. If you make changes to the schema, the sequence of assigning serial numbers can be violated. 3.20. Positional designations are put down on the diagram next to the conditional graphic designations of elements and (or) devices on the right side or above them. 3.21. On the product diagram, which includes devices that do not have independent circuit diagrams, it is allowed to assign positional designations to elements within each device. If the product includes several identical devices, then reference designations should be assigned to the elements within these devices. Ordinal numbers should be assigned to elements according to the rules established in clause 3.18. Elements that are not included in the devices are assigned reference designations, starting from one, according to the rules established in paragraphs. 3.17 - 3.19. 3.22. On the product diagram, which includes functional groups, reference designations are assigned to the elements according to the rules established in paragraphs. 3.17 - 3.19, at the same time, positional designations are first assigned to elements that are not included in functional groups, and then to elements that are included in functional groups. If there are several identical functional groups in the product, the item designations of the elements assigned in one of these groups should be repeated in all subsequent groups. The designation of the functional group, assigned in accordance with GOST 2.710-81, is indicated near the image of the functional group (top or right). 3.23. When an element or device is depicted on the diagram in a spaced way, the reference designation of the element or device is put down near each component (Fig. 4).
If the circuit field is divided into zones or the circuit is made in line, then to the right of the reference designation or under the reference designation of each component part of the element or device, it is allowed to indicate in brackets the zone designations or line numbers that show all the other components of this element or device (Fig. . 5).
3.21 - 3.23. (Revised edition, Rev. No. 2). 3.24. It is allowed, if this does not complicate the scheme, to connect the separately depicted parts of the elements with a mechanical connection line indicating that they belong to one element. In this case, the item designations of the elements are affixed at one or both ends of the mechanical connection line. 3.25. When depicting individual elements of devices in different places, the designation of these elements should include the designation of the device in which they are included, for example, = A 3 -WITH 5 - capacitor C 5 included in the device A 3 . 3.26. With the spaced method of depicting a functional group (if necessary, and with a combined method), the designation of the functional group must be included in the designation of the elements included in this group, for example, ¹ T 1 - WITH 5 - capacitor C 5 included in the functional group T 1. 3.27. With a single-line image, near one conditional graphic symbol, replacing several conventional graphic symbols of the same elements or devices, indicate the positional designations of all these elements or devices. If the same elements or devices are not found in all circuits depicted in a single line, then to the right of the reference designation or below it in square brackets indicate the designations of the circuits in which these elements or devices are located (see Fig. 3). 3.28. On the circuit diagram, all elements and devices that are part of the product and shown on the diagram must be unambiguously identified. Element data must be written to the element list. In this case, the connection of the list with the conditional graphic designations of the elements should be carried out through reference designations. It is allowed in some cases, established in state or industry standards, to place all information about the elements near the conventional graphic symbols. 3.27., 3.28. 3.29. - 3.33. (Deleted, Rev. No. 2). 3.34. In case of complex entry, for example, when a device that does not have an independent circuit diagram includes one or more devices that have independent circuit diagrams and (or) functional groups, or if a functional group includes one or more devices, etc., then in the list of elements in the column "Name" before the name of devices that do not have independent circuit diagrams, and functional groups, it is allowed to put serial numbers (i.e., similar to the designation of sections, subsections, etc.) within the entire scheme of the product (Fig. 9a). ( cm. With. 336 ). If on the diagram the item designation of the element includes the designation of the device, or the designation of the functional group, then in the list of elements in the column “Pos. designation” indicate the reference designation of the element without the reference designation of the device or designation of the functional group. (Revised edition, Rev. No. 2). 3.35. (Deleted, Rev. No. 2). 3.36. When indicating near the conditional graphic designations of the values \u200b\u200bof resistors and capacitors (Fig. 11), it is allowed to use a simplified method for designating units of measurement. for resistors from 0 to 999 ohms - without indicating units of measurement, from 1 × 10 3 to 999 × 10 3 ohms - in kiloohms with the designation of the unit of measurement by a lowercase letter k, from 1 10 6 to 999 × 10 6 ohms - in megaohms s the designation of the unit of measurement with a capital letter M, over 1 × 10 9 Ohm - in gigaohms with the designation of the unit of measurement with a capital letter G; for capacitors from 0 to 9999 × 12 -12 F - in picofarads without indicating the unit of measurement, from 1 × 10 -8 to 9999 × 10 -6 F - in microfarads with the designation of the unit of measurement in lowercase letters MK. 3.37. The diagram should indicate the designations of the leads (contacts) of the elements (devices) applied to the product or installed in their documentation. If the designation of the element (device) and its documentation do not indicate the designations of the leads (contacts), then it is allowed to conditionally assign designations to them on the diagram, repeating them in the future in the relevant design documents.
* Crap. 6 - 9 are excluded. - When conditionally assigning designations to pins to contacts, an appropriate explanation is placed on the circuit field. When depicting several identical elements (devices) on the diagram, it is allowed to indicate the designations of the leads (contacts) on one of them.
* Crap. 10 is excluded. With the spaced method of depicting identical elements (devices), the designations of the leads (contacts) are indicated on each component of the element (device). In order to distinguish the designations of outputs (contacts) from other designations (designations of circuits, etc.) on the diagram, it is allowed to write the designations of outputs (contacts) with a qualifying symbol in accordance with the requirements of GOST 2.710-81. 3.38. When an element or device is depicted in a spaced way, an explanatory inscription is placed near one component of the product or in the diagram field near the image of an element or device made in a combined way. (Revised edition, Rev. No. 3). 3.39. It is recommended to indicate on the diagram the characteristics of the input and output circuits of the product (frequency, voltage, current strength, resistance, inductance, etc.), as well as the parameters to be measured on control contacts, sockets, etc. If it is impossible to indicate the characteristics or parameters of the input and output circuits of the product, then it is recommended to indicate the name of the circuits or controlled quantities. 3.40. If the product is obviously designed to work only in a specific product (installation), then it is allowed to indicate on the diagram the addresses of external connections of the input and output circuits of this product. The address must ensure unambiguous connection, for example, if the output contact of the product must be connected to the fifth contact of the third connector of the device A, then the address should be written as follows: = A - x3 :5 . It is allowed to indicate the address in a general form, if the uniqueness of the connection is ensured, for example, “Device A» . 3.41. The characteristics of the input and output circuits of the product, as well as the addresses of their external connections, are recommended to be written in tables placed instead of conventional graphic symbols for input and output elements - connectors, boards, etc. (Fig. 12).
Each table is assigned a position designation of the element, instead of the conventional graphic designation of which it is placed. Above the table it is allowed to indicate the conditional graphic designation of the contact - a socket or a pin. Tables are allowed to be performed in a spaced way. The order of contacts in the table is determined by the convenience of constructing the circuit. It is allowed to place tables with circuit characteristics if there are conditional graphic symbols of input and output elements - connectors, boards, etc. on the diagram. (Fig. 13).
Similar tables are recommended to be placed on lines depicting input and output circuits and not ending on the diagram with connectors, boards, etc. In this case, positional designations are not assigned to tables. Notes: 1. If there are several tables in the schema, it is allowed to show the head of the table in only one of them. 2. In the absence of characteristics of input and output circuits or addresses of their external connection, the table does not provide a column with these data. If necessary, additional columns can be added to the table. 3. It is allowed to put down in the column "Kont." several consecutive pin numbers if they are interconnected. Contact numbers are separated from each other by a comma. 3.42. When depicting multi-pin connectors on a diagram, it is allowed to use conventional graphic symbols that do not show individual contacts (GOST 2.755-87). Information about the connection of connector contacts is indicated in one of the following ways: - near the image of the connectors, on the free field of the diagram or on subsequent sheets of the diagram, tables are placed that indicate the connection address [circuit designation (Fig. 14a) and (or) positional designation of the elements connected to this contact (Fig. 14b)]. If necessary, the table indicates the characteristics of the circuits and the addresses of external connections (Fig. 14a). If the tables are placed on the diagram field or on subsequent sheets, then they are assigned the positional designations of the connectors to which they are compiled.
The columns of the tables indicate the following data: in the column "Cont." - connector pin number. Contact numbers are recorded in ascending order; in the column "Address" - the designation of the circuit and (or) the positional designation of the elements connected to the contacts. in the column "Chain" - a characteristic of the circuit; in the column "External address" - the address of the external connection; - connections with connector contacts are depicted in a spaced way (Fig. 15).
Crap. 15. (New edition, Rev. No. 3). Notes: 1. Dots connected by a dashed line to a connector indicate connections to the corresponding pins on that connector. 2. If necessary, the characteristics of the circuits are placed in the free field of the circuit above the continuation of the communication lines. (Revised edition, Rev. No. 3). 3.38. - 3.42. (Revised edition, Rev. No. 2). 3.43. When depicting elements on the diagram, the parameters of which are selected during regulation, asterisks are put down near the positional designations of these elements on the diagram and in the list of elements (for example R 1* ), and a footnote is placed on the field of the scheme: "* Selected during regulation." The list should contain elements whose parameters are closest to the calculated ones. The limit values of the parameters of the elements allowed during the selection are indicated in the list in the "Note" column. If the parameter selected during regulation is provided by elements of various types, then these elements are listed in the technical requirements in the field of the scheme, and the following data is indicated in the columns of the list of elements: in the column "Name" - the name of the element and the parameter closest to the calculated one; in the column "Note" - a link to the relevant paragraph of the technical requirements and the limiting values \u200b\u200bof the parameters allowed during selection. 3.44., 3.45. (Deleted, Rev. No. 2). 3.46. If a parallel or serial connection is made to obtain a certain parameter value (capacitance or resistance of a certain value), then in the list of elements in the "Notes" column indicate the total (total) parameter of the elements (for example, R = 151 kOhm). 3.47. (Deleted, Rev. No. 2). 3.48. When depicting a device (or devices) in the form of a rectangle, it is allowed to place tables with the characteristics of input and output circuits (Fig. 18) in the rectangle instead of the conventional graphic symbols of input and output elements, and outside the rectangle it is allowed to place tables indicating the addresses of external connections (Fig. 19 ). If necessary, it is allowed to enter additional columns into the tables.
* Crap. 16, 17 are excluded. Each table is assigned a position designation of the element, instead of the conventional graphic designation of which it is placed. In the table, instead of the word "Cont." it is allowed to place a symbolic graphic designation of the connector contact (see Fig. 19); - on the product diagram, in the rectangles depicting devices, it is allowed to place structural or functional diagrams of devices, or completely or partially repeat their circuit diagrams. The elements of these devices are not recorded in the list of elements. If the product includes several identical devices, then the device diagram is recommended to be placed in the free field of the product diagram (and not in a rectangle) with the appropriate inscription, for example: "Scheme of blocks A1 - A4". (Revised edition, Rev. No. 2). 3.49. - 3.51. (Deleted, Rev. No. 2). 3.52. It is allowed to place indications on the marks, sections and colors of wires and cables (stranded wires, electric cords) on the diagram field, which should be used to connect the elements, as well as instructions on the specific requirements for the electrical installation of this product. (Revised edition, Rev. No. 2).
4. RULES FOR IMPLEMENTATION OF CONNECTION SCHEMES
4.1. The connection diagram must show all devices and elements included in the product, their input and output elements (connectors, boards, clamps, etc.), as well as connections between these devices and elements. 4.2. Devices and elements in the diagram are shown: devices - in the form of rectangles or simplified external outlines; elements - in the form of conventional graphic symbols, rectangles or simplified external outlines. When depicting elements in the form of rectangles or simplified external outlines, it is allowed to place conditional graphic designations of elements inside them. The input and output elements are depicted in the form of conventional graphic symbols. It is allowed to depict input and output elements according to the rules established in paragraphs. 3.41, 3.42 and 3.48. 4.1., 4.2. (Changed edition, Revision, No. 2). 4.3. The location of the graphic symbols of devices and elements on the diagram should approximately correspond to the actual placement of elements and devices in the product. The arrangement of images of input and output elements or outputs within graphic symbols and devices or elements should approximately correspond to their actual placement in the device or element. It is allowed not to reflect the location of devices and elements in the product on the diagram if the diagram is performed on several sheets or the placement of devices and elements at the place of operation is unknown. 4.4. Elements used in the product in part may be depicted in the diagram incompletely, limited to the image of only the parts used. 4.5. In the diagram, near the graphic designations of devices and elements, the reference designations assigned to them on the circuit diagram are indicated. Near or inside the graphic designation of the device, it is allowed to indicate its name and type and (or) the designation of the document on the basis of which the device was used. (Revised edition, Rev. No. 2). 4.6. (Deleted, Rev. No. 2). 4.7. The diagram should indicate the designations of the leads (contacts) of the elements (devices) applied to the product or installed in their documentation. If the designation of the device or element and its documentation do not indicate the designations of input and output elements (outputs), then it is allowed to conditionally assign designations to them on the diagram, repeating them in the future in the relevant design documents. When conditionally assigning designations to input and output elements (outputs), an appropriate explanation is placed on the circuit field. When depicting several identical devices on the diagram, it is allowed to indicate the terminal designations on one of them (for example, the pinout of electrovacuum devices). 4.8. Devices and elements with the same external connections may be depicted in a diagram indicating the connection for only one device or element. 4.9. Devices that have independent connection diagrams may be depicted on the product diagram without showing the connection of wires and cable cores (stranded wires, electric cords) to input and output elements. 4.10. When depicting connectors on a diagram, it is allowed to use conventional graphic symbols that do not show individual contacts (GOST 2.755-87). In this case, tables indicating the connection of contacts are placed near the connector image, on the diagram field or on subsequent sheets of the diagram (Fig. 20). When placing tables on the field of the scheme or on subsequent sheets, they are assigned positional designations of connectors, in addition to which they are compiled.
Crap. 20. (New edition, Rev. No. 3). It is allowed to enter additional columns in the table (for example, wire data). If the bundle (cable - stranded wire, electric cord, group of wires) connects the same-name connector contacts, then it is allowed to place a table near one end of the image of the bundle (cable - stranded wire, electric cord, group of wires). If information about the connection of contacts is given in the connection table, then tables indicating the connection of contacts on the diagram may not be placed. (Revised edition, Rev. No. 3). 4.11. On the product diagram, inside rectangles or simplified external outlines depicting devices, it is allowed to depict their structural, functional or circuit diagrams. 4.12. In the absence of a circuit diagram of the product on the connection diagram, positional designations are assigned to devices, as well as to elements that are not included in the circuit diagrams of the component parts of the product, according to the rules established in paragraphs. 3.16 - 3.20, and write them down in the list of elements. 4.9. - 4.12. (Revised edition, Rev. No. 2). 4.13. On the connection diagram of the product, it is allowed to show external connections of the product according to the rules established in paragraphs. 5.8, 5.9. 4.14. Wires, groups of wires, bundles and cables (stranded wires, electrical cords) must be shown in the diagram as separate lines. The thickness of the lines depicting wires, bundles and cables (stranded wires, electrical holes) in the diagrams should be from 0.4 to 1 mm. To simplify the outline of the diagram, it is allowed to merge individual wires or cables (stranded wires, electrical cords) that run in one direction on the diagram into a common line. When approaching the contacts, each wire and cable core (stranded wire, electric cord) is depicted as a separate line. Lines depicting wires, groups of wires, bundles and cables (stranded wires, electric cords) are allowed not to be drawn or cut off near the connection points if their image makes it difficult to read the diagram. In these cases, on the diagram near the points of connection (Fig. 21) or in the table on the free field of the diagram (Fig. 22), information is placed in an amount sufficient to ensure an unambiguous connection.
Crap. 22. (New edition, Rev. No. 3). 4.15. On the product diagram, which includes multi-contact elements, lines depicting bundles (cables - stranded wires, electrical cords, groups of wires) can only be brought to the contour of the graphic designation of the element, without showing connection to the contacts. Instructions for connecting wires or cable cores (stranded wire, electric cord) to contacts are given in this case in one of the following ways; at the contacts, they show the ends of the lines depicting wires or cable cores (stranded wire, electric cord), and indicate their designations. The ends of the lines are directed towards the corresponding bundle, cable (stranded wire, electric cord), group of wires (Fig. 23); a table indicating the connection of contacts is placed next to the image of a multi-contact element. The table is connected by a leader line with the corresponding bundle, cable, (stranded wire, electric cord) group of wires (Fig. 24). 4.16. The introductory elements through which the wires pass (a group of wires, bundles, cables - stranded wires, electrical cords) are depicted in the form of conventional graphic symbols established in the standards of the Unified Design Documentation System.
A- a line representing a wire (a group of wires, a bundle, a cable - a stranded wire, an electric cord)
Bushings, pressure seals, glands are depicted in the form of conventional graphic symbols shown in Fig. 25. 4.14 - 4.16. (Revised edition, Rev. No. 2). 4.17. The diagram should indicate the designations of the introductory elements applied to the product. If the designations of the input elements are not indicated in the product design, then it is allowed to conditionally assign designations to them on the connection diagram, repeating them in the relevant design documentation. In this case, the necessary explanations are placed on the field of the scheme. 4.18. Single-core wires, bundles, cables (stranded wires, electrical cords) must be marked with serial numbers within the product. Wires, bundles, cables (stranded wires, electric cords) should be numbered separately. In this case, the wires included in the bundle are numbered within the bundle, and the cores of the cable (stranded wire, electric cord) are numbered within the cable (stranded wire, electric cord). Notes: 1. End-to-end numbering of all wires and cable cores (stranded wires, electric cords) within the product is allowed. 2. End-to-end numbering of individual wires, bundles and cables (stranded wires, electric cords) within the product is allowed. In this case, the wires included in the bundle are numbered within the bundle, and the cores of the cable (stranded wire, electric cord) are numbered within the cable (stranded wire, electric cord). 3. It is allowed not to designate bundles, cables (stranded wires, electric cords) and individual wires, if the product for which the diagram is made is included in the complex and designations for bundles, cables (stranded wires, electric cords) and wires will be assigned within the entire complex . 4. It is allowed to assign designations to groups of wires. 4.19. If on the circuit diagram electrical circuits are assigned designations in accordance with GOST 2.709-89, then all single-core wires, cable cores (stranded wires, electric cords) and wire harnesses are assigned the same designations. At the same time, bundles and cables (stranded wires, electrical cords) are designated in accordance with the requirements of clause 4.18. (Revised edition, Rev. No. 3). 4.20. On the diagram, using an alphabetic (alphanumeric) designation, it is allowed to determine the functional affiliation of a wire, bundle or cable (stranded wire, electric cord) to a specific complex, room or functional circuit. An alphabetic (alphanumeric) designation is put down before the designation of each wire, bundle, cable (stranded wire, electric cord), separating it with a hyphen. In this case, the letter (alphanumeric) designation is included in the designation of each wire, bundle and cable (stranded wire, electric cord). The hyphen in the designation is allowed not to be affixed, if this does not confuse the reading of the scheme. If all wires, bundles, cables (stranded wires, electrical cords) shown in the diagram belong to the same complex, room or functional circuit, then the letter (alphanumeric) designation is not affixed, and an appropriate explanation is placed on the field of the diagram. 4.21. The numbers of wires and cores of cables (stranded wires, electrical cords) in the diagram are usually put down near both ends of the images. The numbers of cables (stranded wires, electric cords) are put down in circles placed in breaks in the images of cables (stranded wires, electric cords) near the branching points of the cores. The harness numbers are put down on the shelves of the leader lines near the branching points of the wires. The wire group numbers are put down near the callout lines. Notes: 1. When designating cables (stranded wires, electric cords) in accordance with the requirements of clause 4.20, as well as with a large number of cables (stranded wires, electric cords) running in one direction on the diagram, cable numbers (stranded wires, electric cords) put down in a line break without a circle. 2. When depicting wires, bundles and cables (stranded wires, electric cords) of a large length on the diagram, the numbers are put down at intervals determined by the convenience of using the diagram. 4.22. The diagram should indicate: for single-core wires - brand, section and, if necessary, colors; for cables (stranded wires, electric cords) recorded in the specification as a material, the brand, number and cross section of the cores and, if necessary, the number of occupied cores. The number of occupied cores is indicated in a rectangle placed to the right of the cable data designation (stranded wire, electric cord); for bundles, cables and wires manufactured according to drawings, the designation of the main design document. The diagram shows the characteristics of the input and output circuits of devices and elements or other initial data necessary for the selection of specific wires and cables (stranded wires, electric cords), if, when developing the scheme of the complex, data on wires and cables (stranded wires, electric cords) cannot be defined. The characteristics of the input and output circuits are recommended to be indicated in the form of tables (clause 3.41), placed instead of the conventional graphic symbols of the input and output elements. 4.23. Data (brand, section, etc.) about wires and cables (stranded wires, electric cords) indicate near the lines depicting wires and cables (stranded wires, electric cords). In this case, it is allowed not to assign designations to wires and cables (stranded wires, electric cords). When specifying data on wires and cables (stranded wires, electric cords) in the form of symbols, these designations are deciphered in the field of the diagram. The same brand, section and other data on all or most wires and cables (stranded wires, electric cords) can be indicated in the field of the diagram. 4.24. If the connection points are not indicated on the diagram (for example, individual contacts are not shown in the image of connectors) or it is difficult to find the points of connection of wires and cable cores (stranded wire, electric cord), then data on wires, bundles and cables (stranded wires, electric cords) and the addresses of their connections are summarized in a table called the “Connection Table”. The connection table should be placed on the first sheet of the diagram or performed as a separate document. The connection table, placed on the first sheet of the diagram, is usually placed above the title block. The distance between the table and the title block must be at least 12 mm. The continuation of the connection table is placed to the left of the main inscription, repeating the head of the table. The table of connections in the form of an independent document is performed on A4 format. The main inscription and additional columns to it are performed in accordance with GOST 2.104-68 (form 2 and 2a). 4.25. The form of the connection table is chosen by the designer of the circuit, depending on the information that needs to be placed on the circuit (Fig. 26). The following data is indicated in the columns of the tables: in the column "Wire designation" - the designation of a single-core wire, cable core (stranded wire, electric, cord) or bundle wire; in the columns "Where it comes from", "Where it comes from" - conditional alphanumeric designations of the connected elements or devices; in the column "Connections" - conventional alphanumeric designations of the connected elements or devices, separating them with a comma; in the column "Wire data": for a single-core wire - brand, section and, if necessary, coloring in accordance with the document on the basis of which it is used; for a cable (stranded wire, electric cord) recorded in the specification as a material, the brand, cross section and number of cores in accordance with the document on the basis of which the cable (stranded wire, electric cord) is used; in the column "Note" - additional clarifying data. Notes: 1. Sizes of graphs are recommended. 2. It is allowed to divide the graphs into subgraphs. 4.26. When filling out the connection table, the following order should be followed: when making connections with individual wires, the wires are recorded in the table in ascending order of the numbers assigned to them;
When making connections with wires of bundles or cores of cables (stranded wires, electric cords), before recording the wires of each bundle or cores of each cable (stranded wire, electric cord), a heading is placed, for example: "Bundle 1" or "Bundle ABVG.ХХХХХХ.032"; "Cable 3" or "Cable ABVG.ХХХХХХ.042"; "Wire 5". The wires of the bundle or cores of the cable (stranded wire, electric cord) are recorded in ascending order of the numbers assigned to the wires or cores; when making connections with individual wires, wire harnesses and cables (stranded wires, electrical cords), individual wires (without a header) are first recorded in the connection table, and then (with appropriate headers) wire harnesses and cables (stranded wires, electrical cords); if insulating tubes, shielding braids, etc. are to be put on individual wires, then appropriate instructions are placed in the “Note” column. It is allowed to place these instructions on the field of the scheme. Note. When using a wiring diagram only for wiring, a different recording order is allowed if it is established in industry standards. 4.27. On the connection diagram near both ends of the lines depicting individual wires, wire bundles and cores of cables (stranded wires, electric cords), it is allowed to indicate the address of the connections. In this case, the connection table is not compiled. It is allowed not to assign designations to wires. 4.28. It is allowed to place the necessary technical instructions on the field of the diagram above the main inscription, for example: requirements on the inadmissibility of joint laying of some wires, bundles and cables (stranded wires, electric cords); the minimum allowable distances between wires, bundles and cables (stranded wires, electric cords); data on the specificity of the laying and protection of wires, bundles and cables (stranded wires, electric cords), etc. 4.18. - 4.28. (Revised edition, Rev. No. 2).
5. RULES FOR IMPLEMENTATION OF CONNECTION SCHEMES
5.1. The connection diagram must show the product, its input and output elements (connectors, clamps, etc.) and the ends of wires and cables (stranded wires, electric cords) connected to them for external installation, near which data on the connection of the product are placed [characteristics external circuits and (or) addresses]. 5.2. The product in the diagram is depicted as a rectangle, and its input and output elements are in the form of conventional graphic symbols. It is allowed to depict the product in the form of simplified external outlines. The input and output elements are depicted in this case in the form of simplified external outlines. 5.1, 5.2. (Revised edition, Rev. No. 2). 5.3. The placement of images of input and output elements within the graphic designation of the product should approximately correspond to their actual placement in the product. 5.4. The diagram should indicate the reference designations of the input and output elements assigned to them on the product schematic diagram. 5.5. Lead-in elements (for example, glands, pressure seals, bushings) through which wires or cables pass (stranded wires, electrical cords) are depicted in the diagram according to the rules established in clause 4.16. (Revised edition, Rev. No. 2). 5.6. The diagram should indicate the designations of the input, output or output elements applied to the product. If the designations of input, output and output elements are not indicated in the design of the product, then it is allowed to conditionally assign designations to them on the diagram, repeating them in the corresponding design documentation. In this case, the necessary explanations are placed on the field of the scheme. 5.7. On the diagram, near the symbolic graphic symbols of the connectors to which wires and cables (stranded wires, electric cords) are connected, it is allowed to indicate the names of these connectors and (or) the designations of the documents on the basis of which they are applied. 5.8. Wires and cables (stranded wires, electrical cords) should be shown in the diagram as separate lines. 5.9. If necessary, the diagram indicates the brands, sections, colors of wires, as well as brands of cables (stranded wires, electric cords), the number, cross section and employment of the cores. When specifying brands, sections and colors of wires in the form of symbols in the field of the scheme, these designations are deciphered. 5.7. - 5.9. (Revised edition, Rev. No. 2).6. RULES FOR THE IMPLEMENTATION OF GENERAL SCHEMES
6.1. The general scheme depicts the devices and elements included in the complex, as well as wires, bundles and cables (stranded wires, electrical cords) connecting these devices and elements. 6.2. Devices and elements in the diagram are shown as rectangles. It is allowed to depict elements in the form of conventional graphic symbols or simplified external outlines, and devices - in the form of simplified external outlines. The location of graphic symbols, devices and elements on the diagram should approximately correspond to the actual placement of elements and devices in the product. It is allowed not to reflect the location of devices and elements in the product on the diagram if their location at the place of operation is unknown. In these cases, the graphic designations of devices and elements should be located in such a way as to ensure simplicity and clarity of showing the electrical connections between them. 6.1, 6.2. (Revised edition, Rev. No. 2). 6.3. On the graphic symbols of devices and elements, the input, output and input elements are depicted according to the rules established in paragraphs. 4.10, 4.16. The location of the conventional graphic designations of input, output and input elements inside the images of devices and elements should approximately correspond to their actual placement in the product. If, in order to ensure clarity of the connection display, the location of the graphic symbols of these elements does not correspond to their actual placement in the product, then an appropriate explanation should be placed in the diagram field. 6.4. The diagram should indicate: for each device or element depicted as a rectangle or a simplified external outline, their name and type and (or) designation of the document on the basis of which they are applied; for each element depicted in the form of a conventional graphic designation, its type and (or) document designation. With a large number of devices and elements, it is recommended that this information be recorded in the list of elements. In this case, positional designations are put down near the graphic designations of devices and elements. (Revised edition, Rev. No. 2). 6.5. Devices and elements grouped into posts and (or) rooms are recommended to be recorded in the list by posts and (or) rooms. 6.6. The diagram should indicate the designations of the input, output and input elements applied to the product. If the designations of input, output and input elements are not indicated in the product design, then it is allowed to conditionally assign designations to these elements in the diagram, repeating them in the corresponding design documentation. In this case, the necessary explanations are placed on the field of the scheme. 6.7. On the diagram, it is allowed to indicate the designations of connector documents on the shelves of leader lines, as well as the number of connector contacts, using their following symbolic graphic designation (Fig. 27).
The columns of the list indicate the following data: in the column "Designation" - the designation of the main design document of the wire, cable (stranded wire, electrical cord), bundle, made according to the drawings; in the column "Note" - cables (stranded wires, electric cords) supplied with the complex or laid during its installation; cables (stranded wires, electrical cords) laid during installation may not be included in the list. 6.14, 6.15. (Revised edition, Rev. No. 2). 6.16. The general scheme, if possible, should be performed on one sheet. If the diagram, due to the complexity of the product, cannot be made on one sheet, then: on the first sheet, the product as a whole is drawn, depicting the posts and (or) premises with conditional outlines and showing the connections between the posts and (or) premises. Inside the conditional outlines of posts and (or) premises, only those devices and elements are depicted to which wires and cables (stranded wires, electric cords) are connected to posts and (or) premises. On other sheets, diagrams of individual posts and (or) premises or groups of posts and (or) premises are completely drawn; the general scheme of each complex is performed on a separate sheet if the product includes several complexes. (Revised edition, Rev. No. 2).
7. RULES FOR THE IMPLEMENTATION OF LOCATION SCHEMES
7.1. The layout diagram depicts the component parts of the product, and, if necessary, the connections between them, the structure, room or area on which these component parts will be located. 7.2. The component parts of the product are depicted in the form of simplified external outlines or conditional graphic symbols. 7.3. Wires, groups of wires, bundles and cables (stranded wires, electrical cords) are depicted as separate lines or simplified external outlines. 7.2, 7.3. (Revised edition, Rev. No. 2). 7.4. The location of the graphic designations of the component parts of the product on the diagram should provide a correct idea of their actual placement in the structure, room, on the ground. 7.5. When executing the layout, it is allowed to use various construction methods (axonometry, plan, conditional sweep, section of the structure, etc.). 7.6. The diagram must indicate: for each device or element depicted in the form of a simplified external outline, their name and type and (or) the designation of the document on the basis of which they are applied; for each element depicted in the form of a conventional graphic designation, its type and (or) document designation. With a large number of devices and elements, it is recommended that this information be recorded in the list of elements. In this case, positional designations are put down near the graphic designations of devices and elements. (Revised edition, Rev. No. 2). Sec. 8. (Deleted, Rev. No. 2).APPLICATION
Reference
Information data on compliance with GOST 2.702-75 ST SEV 1188-78
|
Partition number GOST 2.702-75 |
Partition number ST SEV 1188-78 |
Partition number GOST 2.702-75 |
Partition number ST SEV 1188-78 |
The circuit diagram is the most complete electrical circuit of the product, which depicts all the electrical elements and devices necessary for the implementation and control of the specified electrical processes in the product, all connections between them, as well as connection elements (connectors, clamps) that end the input and output circuits . The diagram may show connecting and mounting elements installed in the product for design reasons.
Electrical elements in the diagram are depicted by conventional graphic symbols, the style and dimensions of which are established in the ESKD standards (see section 2). Elements used in the product in part, it is allowed to depict not completely, but only the parts used.
Schemes are performed for products that are in the off position. In technically justified cases, it is allowed to depict individual elements of the circuit in the selected working position, indicating in the field the mode for which these elements are depicted.
Conditional graphic designations of elements and devices are performed in a combined or spaced way. With the combined method, the components of elements or devices are shown on the diagram as they are located in the product, i.e., in close proximity to each other. With the spaced method, the conventional graphic symbols of the component parts of the elements are placed in different places of the circuit, taking into account the order in which the current passes through them (i.e., in series) so that the individual circuits are depicted most clearly. In an exploded way, you can draw as separate elements or devices (for example, windings and contact groups of relays, contacts of plug connectors, halves of a combined radio
lamps, etc.). as well as the entire scheme. Separately depicted parts of the elements can be connected by a mechanical connection line (dashed line). When depicting elements in a spaced way, it is allowed to place conditional graphic symbols of elements made in a combined way on the free field of the scheme. At the same time, the elements used in the product in part are depicted in full with an indication of the used and unused parts (for example, all relay contacts). The conclusions of the unused parts are shown shorter than the conclusions of the used ones (Fig. 1.11.1).
On fig. 1.11.2, a schematic diagram of remote control of the engine using a magnetic starter is shown in combined (Fig. 1.11.2, a) and spaced (Fig. 1.11.2.6) methods.
It is recommended to carry out schemes in a line way: conditional graphic designations of elements or their components, in accordance with the functional purpose, are grouped into horizontal and vertical circuits. In this case, the chains are numbered with Arabic numerals (Fig. 1.11.3).
Schemes are performed in a multi-line or single-line image. With a multi-line image, each circuit is depicted as a separate line, and the elements in the circuits are represented by separate symbols, as shown in Fig. 1.11.4, a. With a single-line image, circuits that perform identical functions are depicted with one line, and the same elements of these circuits are depicted with one symbol (Fig. 1.11.4, b). A single-line image is recommended to simplify the drawing of diagrams with a large number of communication lines and their long length (for example, circuit diagrams of power circuits). Single-line and multi-line images of circuits and conditional graphic designations of elements according to ESKD are given in sec. 2.
The scheme, in addition to the image, includes inscriptions characterizing the input and output circuits, item designations of elements and a list of elements.
Positional designations of elements. All elements and devices depicted in the diagram are assigned conditional alphanumeric designations in accordance with GOST 2.710-81.
Positional designations for elements (devices) are assigned within the product. Serial numbers to elements (devices) starting from one, are assigned within a group of elements (devices) with the same letter designation of one group or one type in accordance with the sequence of their arrangement on the diagram from top to bottom in the direction from left to right, for example R1, R2 ... ...... C1, C2 (Fig. 1.11.5). Letters and numbers of positional designation
They are drawn in a drawing font of the same size.
The sequence of assignment of serial numbers can be violated depending on the placement of product elements, the direction of signal flow or the functional sequence of the process, as well as when changes are made to the scheme.
Positional designations are put down on the diagram next to the conditional graphic designations of elements and devices on the right side or above them.
On the product diagram, which includes devices, reference designations are assigned to elements within each device, and if there are several identical devices, within these devices according to the rules set forth above.
If the product includes functional groups, then first designations are assigned to the elements that are not included in the functional groups, and then to the elements included in the functional groups. For the same functional groups, for example A1, A2 (Fig. 1.11.6), the reference designations of the elements assigned in one of them are repeated in all subsequent groups.
The designation of the device is indicated above or to the right of the image (Fig. 1.11.7, a). With the spaced image method, reference designations are put down near each component (Fig. 1.11.7, b).
It is allowed to connect the separately depicted parts of the elements with a mechanical connection line, putting down the reference designations of the elements at one or both ends of this line.
If the circuit field is divided into zones or the circuit is made in a line way, then to the right of the reference designation under the reference designation) of each component part of the element or device indicate in brackets the zone designations or line numbers in which all other components of this element or device are located (Fig. 1.11.8).
With the spaced method of depicting the elements included in the device or functional group, the reference designation of these elements should include, respectively, the reference designation of this device or functional group, for example, = AZ-C5 - capacitor C5 included in the device A3 or ATI -C5 - capacitor C5 , which is part of the ATI functional group.
With a single-line diagram image, near the symbolic graphic symbol that replaces the symbols of several identical elements, indicate the reference symbols of all replaced elements, for example, SI. . . S3 (see Fig. 1.11.4, b). If the same elements are not found in all the circuits depicted in a single line, then to the right of the reference designation or below it in square brackets indicate the designations of the circuits containing these elements, for example, elements A1, C1 (see Fig. 1.11.4, b).
If tables are placed instead of the conventional graphic designations of the input and output elements of the product, then each table is assigned the positional designations of the replaced element.
List of elements. Data about the elements and devices shown in the product diagram are recorded in the list of elements. It is allowed to place all information about the elements next to their image in the free field of the scheme. The connection between the conventional graphic symbols and the list of elements is carried out through positional symbols.
The list is placed on the first sheet of the diagram or is performed as an independent document on an A4 sheet with a main inscription for text documents in accordance with form 2 or 2a GOST 2.104-68. The list of elements is drawn up in the form of a table and filled in from top to bottom. The columns of the list indicate the following data:
common name record the name, type and designation of the document on the basis of which these elements are applied.
If reference designations are assigned to elements within devices or the same functional groups, then elements related to devices and functional groups are recorded separately in the list. The entry of the elements included in each device (functional group) begins with the name of the device or functional group, which is recorded in the column "Name" and underlined. On the same line with the name in the column "Number." indicate the total number of identical devices or functional groups, and for elements in the "Number" column - the number of elements included in one device (functional group).
Below the name of the device (functional group) leave one free line, above - at least one free line. -
This recording method is also allowed for unequal functional groups included in the product.
If there are elements on the diagram that are not included in the devices (functional groups), filling in the list begins with the entry of these elements (without a heading). Then devices are recorded that do not have independent circuit diagrams, as well as functional groups with their constituent elements.
In case of a complex entry, when a device that does not have an independent circuit diagram includes devices that have independent circuit diagrams, or devices are included in a functional group, then the corresponding headings can be numbered (similar to the designation of sections and subsections) within the entire product diagram, for example: „ 1. Switching block", "1.1. Meter" (see Fig. 1.11.10).
If on the diagram the reference designation of the element includes the designation of the device or functional group, then the list indicates the designation of the element without the designation of the device (functional group).
For elements that are not independent structures, the “Name” column of the list is not filled in, and in the “Note” column, an explanatory inscription or a link to the inscription placed on the diagram field is recorded. If the parameters of the elements are selected when adjusting the product, then on the diagram and in the list they are designated with an asterisk R1 *), and a footnote "* Selected during regulation" is placed in the field of the diagram. Elements whose parameters are closest to the calculated ones are entered in the list. When selecting the limit values of the parameters, indicate in the "Note" column.
If the parameter selected during regulation is provided by elements of various types, then these elements are given in the technical data in the field of the diagram, and the following data is indicated in the columns of the list: in the column "Name" - the name of the element and the parameter closest to the calculated one; in the column "Note " - a link to the corresponding paragraph of the technical requirements and the limiting values \u200b\u200bof the parameters allowed during the selection.
If a certain value of the parameter is obtained by connecting the elements in parallel or in series, then the total parameter is indicated in the "Note" column of the list (for example, R = 151 kOhm).
When developing several independent circuit diagrams for one product, each diagram should contain a list of only those elements whose reference designations are assigned in this diagram. When re-displaying individual elements on several diagrams, they retain the reference designations assigned to them on one of the diagrams. In this case, instructions are placed on the diagrams according to the type: “Elements shown on the diagram and not included in the list, see ABCD.XXXXXXX.XXXEZ.
The diagrams should indicate the designations of electrical contacts or leads from elements (devices) actually applied to the product or indicated in its documentation (numbers of relay contacts, plug connectors, numbers or designations of transformer leads, radio tube pinout, etc.). If neither in the design of the element (device) nor in its documentation the designations of contacts or conclusions are indicated, then it is allowed to assign designations to them in this diagram, repeating them in the future in the relevant design documents. In this case, the necessary explanation on the field of the diagram will interfere.
When depicting several identical elements (devices) on the diagram, it is allowed to indicate the designations of the leads (contacts) on one of them, and when the image is spaced apart, on each component part of the element or device. To distinguish pin numbers on the diagram from other digital designations (for example, circuit designations), it is allowed to write them with a qualifying symbol in accordance with GOST 2.710-81.
On the product diagram, it is allowed to depict individual elements that are not included in this product, but necessary to explain the principle of its operation. The graphic designations of these elements are separated from the main scheme by a thin dash-dotted line with two dots.
The diagram shows connectors, terminals and other elements that terminate the input and output circuits, and indicate the characteristics of the input and output circuits of the product (voltage, current, frequency, etc.), as well as the parameters to be measured on the control contacts, nests. If these indications are not possible, it is recommended to indicate the name of the circuits or controlled values.
On product diagrams that are intended for use only in a specific installation, it is allowed to indicate the addresses of external connections to which the input and output circuits of this product are connected. The address must ensure unambiguous attachment. Address designation is carried out in accordance with GOST 2.710-81, for example, "= A-X3: 5", which means: the output contact of the product must be connected to the fifth contact of the third connector of device A. When ensuring unambiguous connection, the address can be indicated in a general form, for example " Device A.
It is recommended that instead of the conventional graphic symbols of the connecting elements, place tables with the characteristics of the input and output circuits of the product and the addresses of their external connections (Table 1.11.1). In the absence of such characteristics or addresses, the column with these data in the table is not given. If necessary, additional columns are introduced into the table.
Table 1.11.1
F=0.3. ..ZkHz; R H = 600 Ohm |
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Uout=0.5V; R H = 600 Ohm |
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Uout=+60V; R H \u003d 500 Ohm |
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Uout=+20V; R H \u003d 1 kOhm |
|||
Each table is assigned a reference designation of the replaced element, for example, X1 (see Table 1.11.1). Above the table it is allowed to indicate the conditional graphic designation of the contact - a socket or a pin. Tables are allowed to be performed in a spaced way.
The contact numbers in the table can be arranged out of order, but based on the convenience of constructing the circuit. It is allowed to put in the column "Cont." several consecutive numbers of contacts (separated by commas), if they are electrically interconnected.
The same tables are placed on lines depicting input and output circuits and not ending on the diagram with connectors, boards, etc. In this case, reference designations are not assigned to tables.
If there are several tables in the schema, it is allowed to show the head of the table in only one of them.
Information about the connection of the contacts of the multi-pin connectors is indicated in one of the following ways.
1. Near the image of the connectors or in the free field of the diagram, tables are placed indicating the address of the connection, the designation of the circuit (Table 1.11.3) or the reference designation of the elements connected to this contact). If necessary, in the table. 1.11.2 indicate the characteristics of the circuits and addresses of external connections (see Table 1.11.2).
If the tables are placed on the diagram field or on subsequent sheets, then they are assigned the positional designations of the connectors to which they are compiled (see Table 1.11.2). A table is placed near the image of the connector. 1.11.3.
External address |
|||
In the columns of the tables indicate:
In the column "Kont." - the numbers of the contacts (in ascending order); in the column "Address" - the designation of the circuit or positional designations of the elements connected to the contact;
In the column "Chain" - the characteristics of the circuit;
In the column "External address" - the address of the external connection.
2. Connections with connector pins are depicted in a spaced way
(Fig. 1.11.11).
When depicting devices in the form of rectangles, it is allowed in the rectangle, instead of the conventional graphic designations of input and output elements, to interfere with tables with the characteristics of input and output circuits (Table 1.11.4; 1.11.5), and outside the rectangle - tables indicating the addresses of external connections (Table 1.11.6; 1.11.7).
If necessary, additional columns are introduced into the tables. Each table is assigned the reference designation of the replaced element, for example, XI; X2.
In the table, instead of the word "Cont." it is allowed to place a conventional graphic designation of the connector contact (see Table 1.12.6).
In rectangles depicting devices that have independent electrical circuit diagrams, it is allowed to place their structural or functional diagrams, or repeat circuit diagrams. The elements of these devices are not included in the list.
If the product includes several identical devices, then the device diagram is placed not in a rectangle, but in a free field, with an inscription like: "Scheme of blocks A1 -A4".
It is allowed to place instructions on the brands, sections and colors of connecting wires and cables, as well as special instructions for the electrical installation of the product on the diagram field.
When performing a circuit diagram on several sheets, the following requirements must be met:
1) the numbering of the item designations of the elements must be end-to-end within the product (installation);
2) the list of elements should be general;
3) when re-imaging individual elements on other sheets of the diagram, the reference designations assigned to them on one of the sheets of the diagram should be retained.
Diagram simplifications. 1. To reduce the number of lines on the diagram and simplify its drawing and reading, it is recommended to merge separate electrically unconnected lines into a group communication line and interrupt the connection lines of elements that are distant from each other (see clause 1.8). When merging lines into a group communication line, it is recommended to depict each line as a separate line when approaching contacts. Each merged line should be marked at the point of confluence, and, if necessary, at both ends. Designations can be numeric, alphabetic, or alphanumeric. It is allowed to use the designations established by GOST 2.709-72 for electrical circuits.
2. If the product has several identical elements (devices, functional groups) connected in parallel, it is allowed to depict only one branch, indicating the number of branches using the branch designation. Near the conditional graphic designations of the elements, their positional designations are put down. In this case, all the elements included in this connection are taken into account (Fig. 1.11.12, a).
When several identical elements (devices or functional groups) are connected in series, it is allowed to depict and designate (taking into account the missing ones) only the extreme elements (Fig. 1.11.12, b). The electrical connections between them are shown by dashed lines with an indication of the total number of identical elements above them.
In these cases, the elements in the list are written in one line.
3. When indicating near the conditional graphic designations of resistors and capacitors (Fig. 1.11.13), it is allowed to designate units of measurement in a simplified way: for resistors with resistance from 0 to 999 Ohm - without indicating the unit of measure: from 1,103 to 999,103 Ohm - in kiloohms with the designation of the unit of measurement with a lowercase letter "k"; from 1 108 to 999 108 Ohm - in megaohms with a capital letter "M"; over 1 109 ohms - in gigaohms with a capital letter "G".
For capacitors with a capacity from 0 to 9999 10 -12 F - in picofarads without indicating the unit of measurement, for example, 0.01; 0.2; 30.0; from 1 10-8 to 9999 10-6 F - in microfarads with the designation of the unit of measurement in lowercase letters, mk ".
4. If the product includes identical devices that have independent circuit diagrams, then they are depicted in the form of rectangles or conditional graphic symbols with the assignment of reference designations. Rectangles are made with a solid line, equal in thickness to the communication lines.
5. Identical functional groups or identical devices that do not have independent circuit diagrams, for example, triggers, amplifiers, etc., are represented on the diagrams in the form of repeating rectangles depicted by dash-dotted lines indicating the code assigned to them: A1, A2,. . . A7 (Fig. 1.11.14) A schematic diagram of such a device or functional group is depicted inside one (larger) rectangle or in the field of the diagram with the corresponding inscription, for example, "Scheme of the block ABVG.ХХХХХХ.ХХХ".
The electrical circuit is a document in which, according to the GOST rules, the connections between the component parts of devices operating due to the flow of electricity are indicated. As you understand, this drawing gives electricians an understanding of how the installation works and what elements it consists of. The main purpose of the electrical circuit is to help in connecting installations, as well as troubleshooting in the circuit. Next, we will tell you what types and types of electrical circuits are, providing a brief description, characteristics and examples of each variety.
General classification
First you need to understand what is meant by types and what is meant by types of documents. So, according to GOST 2.701-84, there are the following types of schemes (short designation in brackets):
- Electrical (E).
- Hydraulic (D).
- Pneumatic (P).
- Gas (X).
- Kinematic (K).
- Vacuum (B).
- Optical (L).
- Energy (P).
- Divisions (E).
- Combined (C).
As for types, the main ones are:
- Structural (1).
- Functional (2).
- Principal (complete) (3).
- Connections (mounting) (4).
- Connections (5).
- General (6).
- Location (7).
- United (8).
Based on the indicated designations, it is possible to understand its type and type by the name of the electrical circuit. As an example, a document called E3 is a circuit diagram. In appearance, it looks like this:
Next, we will consider in detail the purpose and composition of each of the listed types of electrical circuits. We recommend that you familiarize yourself with this before to make it even easier to understand what each version of the drawing is.
The purpose of each electrical circuit
This type of document is the simplest and gives an understanding of how an electrical installation works and what it consists of. A graphical representation of all elements of the circuit allows you to initially see the big picture in order to move on to a more complex connection or repair process. The reading order is indicated by arrows and explanatory inscriptions, which allows even a novice electrician to understand the structural electrical circuit. You can see the principle of construction in the example below:
The functional wiring diagram of the installation, in fact, is not too different from the structural one. The only difference is a more detailed description of all the components of the chain nodes. This document looks like this:
principled
The circuit diagram is most often used in distribution networks, because gives the most detailed explanation of how the electrical equipment in question works. Such a drawing must necessarily indicate all the functional units of the circuit and the type of connection between them. In turn, a circuit diagram can have two varieties: single-line or complete. In the first case, the drawing shows only primary networks, also called power networks. You can see an example of a single line image below:
A complete circuit diagram can be expanded or elemental. If the electrical installation is simple and all explanations can be applied to one main drawing, it is enough to make a detailed plan. If you are dealing with complex equipment that includes a control, automation and measurement circuit, it is better to spread all the individual nodes on different sheets so as not to get confused. 
There is also a circuit diagram of the product. This type of document is a kind of copying from the general plan, which only indicates how a particular node works and what it consists of.
Mounting
We most often use this kind of electrical circuits on the site when we talk about how to do it ourselves. The fact is that on the wiring diagram you can show the exact location of all the elements of the circuit, the way they are connected, as well as the alphanumeric characteristics of the installations that make up the drawing. If we take as an example, we will see on it where sockets, switches, lamps and other products should be placed.
The main purpose of the wiring diagram is a guide for electrical work. According to the prepared drawing, you can understand where, what and how to connect.
By the way, a wiring diagram is also considered a wiring diagram, which is designed to connect electrical equipment, as well as connect installations to each other within the same circuit. When guided precisely by the wiring diagram.
Well, the last of the electrical circuits used in distribution networks is the combined one, which can include several types and types of documents. It is used if it is possible to indicate all the important features of the circuit without a strong piling up of the drawing. The joint project is used most often in enterprises. Home craftsmen are unlikely to meet this type of scheme. You can see an example below:
There is also a cable route scheme, which is a simplified plan for laying a cable line to distribution points and transformer substations. Its purpose is similar to the wiring diagram - with the help of this document, installers are guided on how to draw a line from point A to point B.
GOST 2.702-75 "Rules for the implementation of electrical circuits" establishes the rules for the implementation of structural, functional, fundamental, connection, connection, general, location, combined and combined electrical circuits of products in all industries. Subject to the general requirements (GOST 2.701-84), additional rules are specified or established taking into account the specifics of the type of schemes. We indicate the most important rules for circuit diagrams.
· Schemes are drawn for products that are in the off position.
· The elements in the diagram are shown as UGOs, the dimensions and thickness of the lines of which are given in GOST 2.747-68 or in other relevant GOSTs. It is allowed, if necessary, to increase or decrease all designations proportionally (the distance between two adjacent lines must be at least 1 mm).
The location of the UGO elements on the diagram should be determined by the convenience of reading the diagram, as well as the need to depict the connections between the elements with the shortest lines with a minimum number of intersections. UGO is performed in combined or spaced ways. With the combined method, the component parts of the elements are depicted in the diagram in close proximity to each other. With the spaced UGO method, the component parts of the elements are located in different places in the circuit in such a way that the individual circuits of the product are depicted most clearly. In a spaced way, it is allowed to draw both the entire scheme and individual elements.
· When drawing diagrams, the line types established by GOST 2.303-68 are used. A solid main line with a thickness of 0.5 ... 1.0 mm depicts UGO, electrical communication lines, frame lines, main inscription, list of elements. A solid thin line is used to underline inscriptions, a dashed line is used to depict mechanical connection lines, a conditional image of identical elements connected in series.
· Each electrical element of the product shown in the diagram must be assigned an alphanumeric reference designation in accordance with the requirements of GOST 2.710-81. According to the specified GOST, resistors are designated - R, capacitors - C, semiconductor devices - V, switches - S, etc. Serial numbers are assigned to the elements, starting from one within a group of elements that have the same letter designations on the diagram, for example, R 1, R 2, R 3 ... (resistors), S 1, S 2 ... (switches). Numeric designations are not assigned if the scheme contains only one element of this name.
Alphanumeric designation of elements is performed in font 3.5 or 5, and the height of letters and numbers should be the same. Ordinal numbers are assigned to the elements in accordance with the sequence of the elements on the diagram from top to bottom in the direction from left to right. Positional designations are put down next to the conditional graphic designations of elements on the right side or above them. Alphanumeric designations can only be applied horizontally.
· It is recommended to indicate the characteristics of the input and output circuits of the product (frequency, voltage, current strength, etc.) on the diagram. Therefore, instead of the conventional graphic designations of the connectors, a table of input or output data is performed. Each table is assigned an item designator, instead of the symbolic symbol it is placed on.
The first column of the table indicates the pin number of the connector. In the "Chain" column, the characteristics of the electrical circuits of the product (frequency, voltage, etc.) are recorded. On fig. 1a shows the sizes of the tables of input and output data and an example of filling. For the convenience of depicting the diagram, the table can be made mirror-rotated, as shown in Fig. 1b.
The table is filled with font 3.5 or 5. The table of input or output data should be placed only horizontally.
Rice. 1. Sample design of input and output data
Rice. 2. Example of a circuit diagram
The diagram is drawn for the device in the disabled state.
Elements of electrical devices are depicted on the diagram in the form of conventional alphanumeric symbols, to which, in the case of their repeated use in the diagram, a digital reference designation is also attached (for example, C2).
The sizes of the conventional graphic symbols of the circuit elements are given in GOSTs 2.710 - 2.751., 2.755 - 68, where their sizes are also given.
The thickness of the lines of conditional graphic images of elements (S) is selected in the range from 0.2 to 0.6 mm (when drawing in natural scale).
The alphanumeric designation of the circuit element (GOST 2.710-81) is placed above its graphic designation, or to the right of it. The font height for letter and positional designations is the same.
The stroke thickness of all circuit elements (including electrical circuits) is exactly the same throughout the drawing within the dimensions indicated earlier.
An example of the task execution is shown in fig. 2.
The list of elements included in the scheme is performed in the form of a table (Fig. 3) and placed on the first sheet of the scheme or performed as an independent document in A4 format. In the latter case, the code of the list of elements must consist of the letter P and the code of the scheme for which the list is issued, for example, the code of the list of elements for the hydraulic circuit diagram - PGZ. At the same time, in the main inscription (column 1) indicate the name of the product, as well as the name of the document - "List of elements"; when performing a list of elements on the first sheet of the diagram, it is usually placed above the main inscription. The distance between the list of elements and the main inscription must be at least 12 mm. The continuation of the list of elements is placed to the left of the main inscription, repeating the table header;
Rice. 3. Sample implementation of the list of elements
The table of the list of elements is filled in from top to bottom in groups in alphabetical order of letter designations: in the column “Pos. Designation" - position designations of elements, devices and functional groups, in the column "Name" - for the element name in accordance with the document on the basis of which this element is used, and the designation of this document, for example, resistor MLT-0, 5-300 kOhm ± 5% GOST 7113-77, in the column "Note" it is recommended to indicate the technical data of the element that is not contained in its name;
Within each group having the same letter reference designations, the elements are arranged in ascending order of serial numbers. Elements of the same type with the same parameters, having sequential serial numbers on the diagram, can be written in the list in one line indicating the smallest and largest numbers, for example, C 8 ... C 12, and in the column "Quantity" - the total number of elements .
When writing elements of the same type, it is allowed not to repeat the name of the element in each line, but to write it in the form of a common name for the corresponding group of elements. In the general name, the name, type and designation of the document are recorded on the basis of which these elements are applied.
Elements included in independent devices or functional groups are recorded in the list of elements separately, starting with the name of the device or functional group, which is recorded in the column "Name" and underlined, and one free line should be left below the name of the device (functional group), above - at least one free line.
Connection diagram (E4)
The connection diagram (mounting) determines the design of the electrical connections of the elements in the product. The diagram shows all the devices and elements that make up the product, their input and output elements (connectors, boards, clamps, etc.) and the connections between them. Devices are designated in the form of rectangles or simplified external combinations, elements in the form of conditional graphic designations established in ESCO standards, rectangles or simplified external combinations.
The input and output elements are depicted by conventional graphic symbols. The location of input and output images or outputs inside the conventional graphic designations of devices and elements should approximately correspond to their actual location in the device or element.
The connection diagram of the radio receiver (Fig. 4, a), in contrast to the circuit diagram (Fig. 4, b), shows the following elements necessary for the installation and operation of the product:
Socket XS1 for antenna connection;
Socket XS1;
Connectors XT1, XT2 for connecting batteries;
Mounting stand X1.
Near the conditional graphic designations of devices and elements indicate the reference designations assigned to them on the schematic diagram.
Rice. 4. Examples of diagrams: a - connection diagram,
b - circuit diagram
Layout plan (E7)
The layout diagram determines the relative location of the component parts of the product, and, if necessary, also bundles, wires, cables. The diagram shows the component parts of the product and, if necessary, the connections between them, as well as the structure, room or area on which these parts are located. The component parts of the product are depicted in the form of simplified external outlines or conditional graphic symbols, which are arranged in accordance with the actual (!) Placement of the parts of the product in the structure or on the ground.
Wires, bundles and cables are depicted as separate lines, or simplified external outlines.
Near the images of devices and elements, their name and types and (or) the designation of the document on the basis of which they are applied are placed. With a large number of components, this information is recorded in the list of elements. In this case, the component parts of the product are assigned positional designations.
Layout schemes can be made on sections of a structure, on sections or plans of buildings, or in axonometry.
On fig. 3 shows the electrical diagram of the location of the welding post, shown in a perspective view. The welding station is shown in the interior of the office space.
The layout scheme is a calculation and graphic work performed by students on their own in order to consolidate and deepen knowledge and develop the ability to apply the theoretical provisions of the discipline being studied and the achievements of science and technology to solve specific practical problems.
The electrical part of the project includes calculation and selection of an electric drive, selection of control and protection equipment, lighting calculations and selection of irradiation installations, calculation of electrical loads, selection of power sources and calculations of external and internal electrical networks.
The project should be based on a production facility and technology from currently operating standard projects. Using the data of these projects, the student is invited to compile a table of the main technological equipment, in which it is necessary to indicate the serial number of the equipment according to the technological scheme, its name and brand, technical data, data on the electrical equipment of these machines and mechanisms.
Then, on the building plan (you can use the architectural and construction drawings of a typical project), you need to show the location of the electrified technological equipment.
Rice. 5. Layout of electrical equipment
For example, electric motors are depicted in circles, a positional designation (Ml; M2; MZ, etc.) written in the numerator is put next to it; and the denominator indicates the power in kilowatts (4.0; 7.5; 10, etc.).
In addition to the plan, the drawing gives a specification for the equipment, which is placed above the main inscription; a list (explication) of the premises in the form of a table containing, for example, the following columns: "number according to the plan", "room", "area, m 2", "category and class of the premises by the nature of the environment"; calculation and installation tables for power and lighting networks, notes, decoding of symbols for wiring routes, lamps, cabinets, etc.
When designing internal electrical wiring, they are guided by the industry standard OST 70.004.0013-81 "Electrical wiring for agricultural production facilities" and PUE.
First, it is necessary to develop a power supply circuit for internal networks and provide a drawing of this circuit in an explanatory note. Then, depending on the nature of the environment, power electrical equipment is placed on the plan: electrical networks for powering electrical receivers and control devices for electric drives.
Familiarization with the implementation of layout schemes in the process of course and diploma design is necessary for students in a number of specialties.
9. Methodological support of the work “Design of electrical
diagrams (principal, connections, layout, etc.)”
During the course of this work, students are given the following tasks:
1. Familiarize yourself with the rules for graphic design of design documents:
- “Electrical circuit diagram”;
- “Electrical connection diagram”;
- “Electrical arrangement diagram”.
2. To instill skills in graphic design of schemes.
3. To instill skills in the use of regulatory, technical and reference information (GOSTs, OSTs, reference books).
In accordance with the tasks set, the student must:
1. Run a circuit with the least number of kinks and intersections of electrical communication lines.
2. Identify the electrical and other elements included in the product using the GOST ESKD specified earlier.
3. Designate the circuit, circuit elements, input and output circuits.
4. Designate identical elements connected in series or in parallel.
5. Complete the list of elements.
The task of performing in term papers and diploma papers on the design of schemes is relevant, because. in connection with complex automation, the proportion of design documents in the form of various schemes is increasing, and knowledge of the conventions and rules for their design is an integral part of the general training of specialists in the specialty 110302 - Electrification and automation of agriculture.
Bibliographic list
1. GOST 2.701-84. Scheme. Types and types.
2. GOST 2.702-75. Rules for the implementation of electrical circuits.
3. GOST 2.710-81. Alphanumeric designations in electrical circuits.
4. GOST 2.722-68; GOST 2.723-68; GOST 2.725-68; GOST 2.727-68; GOST 2.747-68; GOST 2.755-84 Conventional graphic symbols in diagrams.
5. Usatenko S.T. Execution of electrical circuits according to ESKD. Directory / S.T. Usatenko, T.K. Kachenyuk, M.V. Terekhova - M., 1989.
6. Kamnev V.N. Reading diagrams and drawings of electrical installations. - M.: Higher. school, 1990.
Applications
List of standards used in the implementation of schemes
GOST 2.701-84. Scheme. Types and types. General performance requirements.
GOST 2.702-75. Rules for the implementation of electrical circuits.
GOST 2.703-68. Rules for the implementation of kinematic schemes.
GOST 2.704-76. Rules for the implementation of hydraulic and pneumatic circuits.
GOST 2.708-81. Rules for the implementation of electrical circuits of digital computer technology.
GOST 2.710-81. Alphanumeric designations used on electrical circuits.
GOST 2.721-74. Designations for general use.
GOST 2.722-68. Conditional graphic designations in schemes. Machines are electric.
GOST 2.723-68. Conditional graphic designations in schemes. Inductors, chokes, transformers, autotransformers and magnetic amplifiers.
GOST 2.725-68. Conditional graphic designations in schemes. Switching devices.
GOST 2.727-68. Conditional graphic designations in schemes. Dischargers; circuit breakers
GOST 2.728-74. Conditional graphic designations in schemes. Resistors; capacitors
GOST 2.729-68. Conditional graphic designations in schemes. Electrical measuring instruments.
GOST 2.730-73. Conditional graphic designations in schemes. Semiconductor devices.
GOST 2.732-68. Conditional graphic designations in schemes. Sources of light.
GOST 2.742-68. Conditional graphic designations in schemes. Electric current sources.
GOST 2.743-91. Conditional graphic designations in schemes. Elements of digital technology.
GOST 2.747-68. Conditional graphic designations in schemes. Sizes of conventional graphic symbols.
GOST 2.751-73. Conditional graphic designations in schemes. Electrical connections, wires, cables and tires.
GOST 2.755-87. Conditional graphic designations in electrical circuits. Devices switching and contact connections.
GOST 2.756-76. Conditional graphic designations in schemes. Perceiving part of electromechanical devices.
GOST 12.1.114-82. Conditional graphic designations. Fire trucks and equipment.
ST SEV 158-75. Electrical diagrams. General performance requirements
ST SEV 527-77. Electrical diagrams. Classification, terms and definitions.
Table P-1
Sizes of conventional graphic symbols. All geometric elements should be made with lines of the same thickness as the electrical communication lines GOST 2.728-74.
| Name | Designation |
| 1. Resistor constant | |
| 2. Resistor constant with additional taps: a) one | |
| b) two | |
| 3. Variable resistor | |
| 4. Variable resistor with two moving contacts |  |
| 5. Trimmer resistor |  |
| 6. Functional potentiometer |  |
| 7. Functional ring closed potentiometer: a) single winding |  |
| b) multi-winding, for example, two-winding |  |
| 8. Functional ring closed potentiometer with isolated area | |
| 9. Fixed Capacitor | |
| 10. Electrolytic capacitor | |
| 11. Capacitor reference |  |
| 12. Variable Capacitor |  |
| 13. Pass capacitor | |
| 14. Photoresistor: a) general designation | |
| b) differential | |
| 15. Photodiode | |
| 16. Photothyristor | |
| 17. Phototransistor: a) PNP type | |
| b) NPN type | |
| 18. Photocell | |
| 19. Photo battery |  |
| Table A-2 Dimensions (in a modular grid) of the main conventional graphic symbols | |
| Name | Designation |
| 1. Diode | |
| 2. Diode thyristor | |
| 3. Triode thyristor | |
| 4. Transistor | |
| 5. Field effect transistor | |
| 6. Field effect transistor with insulated gate |
Table P-3
Designations of elements in circuit diagrams
| code | element name | designation | |
| A | high voltage switchgear busbars | or | |
| G GC | generator synchronous compensator | ||
| FV | arrester | ||
Table P-4
Letter and conditional graphic designations of elements of electrical circuits
| Switching devices and contact connections GOST 2.755 - 74 | |||||||||||||
| Single-pole switch with closing contact | SA SB | Button | |||||||||||
| Single-pole switch with NC contact | SA SB | Button | |||||||||||
| Two-pole automatic switch | SA | ||||||||||||
| Relay winding | TO | ||||||||||||
| Relay make contact | TO | Dimensions see item 1 | |||||||||||
| Relay break contact | TO | Dimensions see item 2 | |||||||||||
| Plug-in contact (pin) | X | ||||||||||||
| Plug-in contact (female) | X | ||||||||||||
| Inductors, transformers GOST 2.723-68 | |||||||||||||
| Inductor | L | ||||||||||||
| core transformer | T | See dimensions p.1 | |||||||||||
| coreless transformer | T | See dimensions p.1 | |||||||||||
| Resistors, capacitors, fuses GOST 2.728-74 | |||||||||||||
| Resistor | R | ||||||||||||
| variable resistor | R | See dimensions p.1 | |||||||||||
| Capacitor | WITH | ||||||||||||
| electrolytic capacitor | WITH | See dimensions p.3 | |||||||||||
| variable capacitor | WITH | See dimensions p.3 | |||||||||||
| fuse | F | See dimensions p.1 | |||||||||||
| Electrochemical current sources GOST 2.742-68 | |||||||||||||
| Element galvanic or accumulator | G | ||||||||||||
| Battery of galvanic or rechargeable cells | GB | See dimensions p.1 | |||||||||||
| Light sources GOST 2.732-68 | |||||||||||||
| incandescent lighting | EL | ||||||||||||
| Incandescent signal lamp | HL | See dimensions p.1 | |||||||||||
| Photosensitive and light-emitting semiconductor devices GOST 2.730-73 | |||||||||||||
| photoresistor | IN | See dimensions p.4 and GOST 2.728-74 | |||||||||||
| Photodiode | VD | ||||||||||||
| Light-emitting diode | VD | See dimensions p.4 and table p.2 | |||||||||||
| Luminous flux (symbol dimensions) | |||||||||||||
Wiring diagram- this is a text that describes with certain symbols the content and operation of an electrical device or a complex of devices, which makes it possible to express this text in a short form.
In order to read any text, you need to know the alphabet and reading rules. So, to read the schemes, you should know the symbols - symbols and the rules for decoding their combinations.
The basis of any electrical circuit is conventional graphic symbols various elements and devices, as well as connections between them. The language of modern diagrams emphasizes in symbols the main functions that the depicted element performs in the diagram. All the correct conventional graphic designations of the elements of electrical circuits and their individual parts are given in the form of tables in the standards.
Conditional graphic symbols are formed from simple geometric shapes: squares, rectangles, circles, as well as from solid and dashed lines and dots. Their combination according to a special system, which is provided by the standard, makes it possible to easily depict everything that is required: various electrical devices, appliances, electrical machines, mechanical and electrical connection lines, types of winding connections, type of current, nature and methods of regulation, etc.
In addition, special signs are additionally used in the conventional graphic symbols on electrical circuit diagrams to explain the features of the operation of one or another element of the circuit.
So, for example, there are three types of contacts - closing, opening and switching. The symbols reflect only the main function of the contact - closing and opening the circuit. To indicate the additional functionality of a particular contact, the standard provides for the use of special signs applied to the image of the moving part of the contact. Additional signs allow you to find contacts, time relays, limit switches, etc. on the diagram.
Individual elements on electrical diagrams have not one, but several designations on the diagrams. So, for example, there are several equivalent options for designating changeover contacts, as well as several standard designations for transformer windings. Each of the designations can be used in certain cases.
If the standard does not contain the required designation, then it is compiled based on the principle of operation of the element, designations adopted for similar types of apparatus, instruments, machines in compliance with the construction principles stipulated by the standard.
Standards. Conventional graphic symbols on electrical and automation diagrams:
GOST 2.710-81 Alphanumeric designations in electrical circuits:
