How to read electrical drawings

Electrical drawings are indispensable tools in the design, construction and maintenance of electrical engineering. It not only records the layout, wiring and control logic of electrical equipment, but also is an important basis for technicians to install, debug and troubleshoot. Therefore, it is very important for people engaged in electrical work to master the correct reading method of electrical drawings.

First, understand the basic types of electrical drawings

There are many kinds of electrical drawings, and the common ones are as follows:

1. Electrical system diagram: It reflects the overall structure of the whole electrical system and the relationship between various parts, and is a macro-level design drawing.
2. Electrical schematic diagram: It shows the control relationship and working principle between electrical devices, and is often used to analyze circuit functions.
3. Electrical wiring diagram: shows the actual wiring mode between devices in detail, which is used to guide the field wiring operation.
4. Layout plan: shows the specific installation location of electrical equipment on site, such as distribution box, lamps and sockets.
5. Secondary circuit diagram: used to describe the connection of auxiliary circuits such as relay protection and automatic control.

Second, familiar with electrical graphic symbols and text symbols.

A large number of graphic symbols and text labels are used in electrical drawings, which are the basis of reading drawings. Common electrical components, such as circuit breakers (QF), contactors (KM), relays (KA), fuses (FU), buttons (SB) and indicator lights (HL), all have their standard graphic symbols. In addition, it is necessary to master the meaning of text symbols, such as "L" for live wire, "N" for neutral wire and "PE" for ground wire.

Third, master the general steps of reading drawings

1. Look at the drawing description first: The drawing description usually contains important information such as the purpose, design basis and equipment parameters of the drawing, which is helpful to understand the overall content of the drawing.
2. First the whole and then the part: first, start with the system diagram or schematic diagram to understand the overall structure and working principle of the system; Then go deep into the wiring diagram and floor plan to see the specific wiring mode and equipment location.
3. Combined with the equipment manual: For complex components or control systems appearing in drawings, we should understand them in combination with the equipment manual to ensure the accuracy of reading.
4. Pay attention to the marking and legend of the drawings: the marking and legend in the drawings are the key to understanding the drawings, especially the information such as line number, equipment number and control logic, which must be carefully checked.

Fourth, practical application and experience accumulation

Theoretical knowledge can only be truly mastered through practice. Beginners can improve their ability to read drawings by analyzing actual engineering drawings, participating in on-site construction and equipment debugging. At the same time, we should be good at summing up experience, accumulating common circuit reading methods, and gradually improve our professional level.

In a word, electrical drawings are the "language" of electrical engineering. To read electrical drawings, it is necessary not only to master basic knowledge, but also to improve skills through continuous study and practice. Only by truly understanding the contents of the drawings can we be handy in practical work and ensure the quality and safety of the project.