Electrical control system principle of graphics, symbols and graphics

Graphic symbol graphic symbol is usually used in the drawings or other documents, to the concept of a device or graphics, tag, or character. Text text symbols are divided into basic text symbols and auxiliary words symbols. Text symbols applied to electrical technology in the field of technical documents, can also be said on the electrical equipment, devices and components or its nearby to indicate their name, the function, status and characteristics. Main circuit of each contact tag three-phase ac power supply lead in using L1, L2, L3 tag. After the power switch of the three-phase ac power main circuit respectively according to the U, V, W tag sequence. Classification of three-phase ac power main circuit adopts three-phase writing code in front of U, V, W and Arabic numerals, 1, 2, 3, etc. To tag, such as 1 U, V, 1 W; 2 u, v, 2 w, etc. Second, the drawing principle of electrical control system diagram including electrical schematic diagram, electrical installation drawing ( Electrical installation drawing, interconnection network) And the block diagram, etc. All sorts of figure drawing size generally choose 297 x 210, 297 * 420, 297 by 630, 297 * 840 ( 毫米) Four kinds of wide, special needs can press GB126 - 74 'mechanical drawing' national standard to choose other size.