The first step: See the electrical equipment in the main circuit. Electrical equipment refers to the consumption of electrical appliances or electrical equipment, the drawing must first see how many electrical appliances, their categories, uses, wiring methods and some different requirements.
Step 2: Find out what electrical components are used to control the electrical equipment. There are many ways to control electrical equipment, some are controlled directly by switches, some are controlled by various starters, and some are controlled by contactors.
Step 3: Understand the control and protection appliances used in the main circuit. The former refers to other control components other than conventional contactors, such as power switches (transfer switches and air circuit breakers) and universal transfer switches. The latter refers to the short circuit protection devices and overload protection devices, such as the specifications of the electromagnetic release device and the thermal overload release device in the air circuit breaker, the uses and specifications of the components such as fuses, thermal relays and overcurrent relays. In general, after the analysis of the main circuit as above, the auxiliary circuit can be analyzed.
Step 4: Look at the power supply. To understand the power supply voltage level, is 380V or 220V, from the bus bus power supply or distribution panel power supply, or from the generator group.
