In China's economic and social development and people's daily life, the use of electromagnetic energy is becoming more and more common. Electrification is even more indispensable for the completion of intelligent industrial production, agriculture and animal husbandry, national defense security, and scientific and technological progress. In order to better safety and reliable application of electromagnetic energy, the power supply circuit must be equipped with a variety of electrical equipment. This kind of electrical equipment is commonly known as electrical appliances, which are divided into high-voltage electrical appliances and bottom-voltage electrical appliances according to the working standard voltage and M. Electrical appliances with power supply circuits above 5kV are commonly known as high-voltage electrical appliances. The bottom voltage electrical appliance is used to communicate with the electrical appliances in the power supply circuit of 50H or 60Hz, with a rated current of 1200V and below, or a direct current of 1500V and below. It plays the function of maintenance, operation, adjustment, conversion and conduction in the power supply system, and there are various types of under-voltage electrical appliances, according to the main purpose of its structure and the target of the operation, there can be different classification methods.

(1) According to the main purpose and operation target, the main use and operation target are different, and the bottom voltage electrical appliance can be divided into power distribution equipment electrical appliances and control electrical appliances. Power distribution equipment and electrical appliances used for bottom voltage power grids, including knife switches, transfer switches, air circuit breakers and circuit breakers, etc. The key technical standards for electrical appliances for power distribution equipment are strong ability to cut off the current, good practical effect of overcurrent protection, ensure correct posture when the system software produces common faults, reliable work, sufficient heat resistance and dynamic reliability.

The key to manipulating electrical appliances is to power drag and fully automatic automatic control systems. The key ones are AC contactors, drivers, master appliances, and various operating relays. The key technical standards for the operation of electrical appliances are moderate conversion work ability, high actual operation frequency, electrical service life and long life of mechanical equipment. The control appliances used for electric traction and automatic control systems include AC contactors, drives, master appliances and various control relays. The key technical standards for the operation of electrical appliances are the actual operation frequency quotient, long service life and corresponding transformation work ability.

DC circuit breaker DC power supply network power supply circuit, DC circuit breaker has the role of load long delay maintenance, short circuit fault instantaneous maintenance, DC circuit breaker is used to distribute electromagnetic energy and maintenance routes and power supply equipment to avoid load, short circuit fault and other common faults.

DC circuit breaker can also be used in solar power station system software, which can quickly break the common fault current of DC power distribution system, and maintain the key component in the solar power station system software - solar power generation control module to avoid the damage of the communication side feedback current caused by the reverse current amount of DC side and the common fault of inverter power supply, and the reliable operation of DC circuit breaker photovoltaic power generation system software. The actual operation organization of DC circuit breaker has the effect of rapid closing and rapid breaking, compact structure, small size, and easy to use.

(2) According to the posture method, the low-luck electrical appliances can be divided into automatic electrical appliances and manual electrical appliances. Fully automatic electrical appliances refer to electrical appliances that are connected, interrupted, operated, reversed and terminated. It was created by its own main parameters, rather than by human beings immediately and practically. Common automatic conversion appliances include control switches, AC contactors, etc.