The general way to look at the electrical control circuit diagram is to look at the main circuit first, then at the auxiliary circuit, and use the loop of the auxiliary circuit to study the control program of the main circuit. Electrical control schematic diagram is generally divided into two parts: main circuit and auxiliary circuit. The main circuit is the part of the electrical control circuit where a large current flows, including the electrical components connected to the motor from the power supply. The auxiliary circuit is the circuit except the main circuit in the control circuit, and the current flowing is relatively small. Main circuit analysis: \x0d\ No matter circuit design or circuit analysis, we should start with the main circuit first. The function of main circuit is to ensure the realization of machine tool drag requirements. From the composition of the main circuit, we can analyze the types, working methods, control requirements and protection requirements of starting, steering, speed regulation and braking. \x0d\ Analysis of control circuit: \x0d\ The control requirements of the main circuit are realized by the control circuit. Based on the principles of "breaking the whole into parts" and "tracing to the source", the control loop is divided into several local control loops according to functions. Based on the power supply and command signal, the control flow is written by logical judgment, and the automatic working process of the circuit is expressed simply and clearly. \x0d\ Analysis auxiliary circuit: \x0d\ Auxiliary circuit includes working state display, power supply display, parameter measurement, lighting and fault alarm of actuator. This part of the circuit is relatively independent, plays an auxiliary role and does not affect the main functions. Many parts of the auxiliary circuit are controlled by elements in the control circuit. \x0d\ Interlocking and protection link analysis: \x0d\ Production machinery requires high safety and reliability. In order to achieve these requirements, in addition to the reasonable selection of drag and control scheme, a series of electrical protection and necessary electrical interlocking are also set in the control circuit. In the analysis process of electrical control schematic diagram, electrical interlocking and electrical protection are important contents, which cannot be omitted. \x0d\ Overall inspection: \x0d\ After "breaking the whole into parts", the working principle of each local circuit and the control relationship between each part are gradually analyzed, and the whole control circuit must be inspected by "breaking the whole into parts" to see if there are any omissions. In particular, it is necessary to further check and understand the relationship between control links from a global perspective, so as to correctly understand the functions of various electrical components in the schematic diagram. \x0d\ 1。 Steps to look at the main circuit \x0d\ Step 1: Look at the electrical equipment in the main circuit \x0d\ Electrical equipment refers to electrical appliances or electrical equipment that consume electricity. When looking at pictures, we should first see clearly how many electrical appliances there are, their categories, uses, connection methods and some different requirements. \x0d\ Step 2: Find out what electrical components are used to control electrical equipment. \x0d\ There are many control methods for electrical equipment, some are directly controlled by switches, some are controlled by various starters, and some are controlled by contactors. \x0d\ Step 3: Understand the control and protection appliances used in the main circuit. \x0d\ The former refers to other control elements besides conventional contactors, such as power switches (transfer switches and air and cam switches). The latter refers to the specifications of short-circuit protection devices and overload protection devices, such as electromagnetic release and thermal overload release in air switches, and the uses and specifications of fuses, thermal relays and overcurrent relays. Generally speaking, after analyzing the main circuit as above, you can analyze the auxiliary circuit. \x0d\ Step 4: Look at the power supply \x0d\ and know the power supply voltage level, whether it is 380V or 220V, bus power supply, distribution panel power supply or generator set power supply.