What are the 21 electrical letter symbols?

The form of electrical graphic symbols is divided into 2 main categories:

I. Graphic symbols

1. Basic symbols

2. General symbols

3. Detailed symbols

4. Derived symbols

Two. Textual symbols

1. Basic textual symbols

(1) Single-letter symbol

(2) double-letter symbols

2, auxiliary text symbols

Electrical schematic diagram labeling

Commonly labeled: QS knife switch, FU fuses, KM contactors, KA intermediate relays, KT time relays, KS speed relays, FR thermal relays, SB buttons, SQ Travel switches.

Component technical data

(1) Electrical component breakdown: component name, symbol, function, model, quantity, etc..

(2) Note in small font next to the graphic symbols in its electrical schematic diagram.

Reference: Baidu Encyclopedia-Electrical Schematic Diagram