Electrical schematic terminal block marking specification

Electrical schematic lines are marked with letters, numbers, symbols, and combinations thereof.

(1) The three-phase AC power supply lead-in line is marked with L1, L2, and L3, the neutral line is marked with N, and the protection line is marked with PE.

(2) The main circuit of the three-phase AC power supply after the power switch is marked in the order of U, V, and W, respectively.

(3) The main circuit of the three-phase AC power supply is marked by adding the Arabic numerals 1, 2, 3, etc. after the three-phase characters U, V, W, such as U1, V1, W1 and U2, V2, W2, and so on.

(4) Each terminal of each motor branch circuit is marked with a three-phase text code followed by a number. The single digit in the number indicates the motor code, and the ten digit indicates the code of each contact of the branch. Press from top to bottom. Number size order mark. For example, U11 represents the code of the first terminal of the first phase of the M1 motor, U21 is the code of the second terminal of the first phase of the motor, and so on.

(5) The first end of the motor winding is marked with U, V, W, and the tail ends are marked with U', V', W', and the points of the double winding are marked with U", V", W".

(6) The control circuit adopts the Arabic numeral numbering, and the labeling method is carried out according to the principle of “equal potential”. In the circuit drawn vertically, the numbers are generally numbered from top to bottom and from left to right. Any terminal that is separated by components such as coils and contacts shall be marked with different numbers. The number 2 between the control buttons SB1 and SB3 indicates the three layers, which are the outlet terminal number of the control button SB1, the connection SB1 and This wire number of the SB3 and the incoming terminal number of the control button SB3.