1. Preface 　　 This case comes from the electrical project of the heavy oil catalytic cracking unit of Shandong Chengda New Energy Technology Co., Ltd., which is served by our company. Due to the key role of the main fan unit in the catalytic cracking process, the control and protection of the main fan unit have always been people's attention, especially the large-scale axial flow fan, which has many and strict restrictions on the stable working condition area, and once it fails, economic losses It is so heavy, so the control and protection of the axial flow fan has always been the focus and difficulty in the automatic control design.

The No. 712 Research Institute of China Shipbuilding Industry Corporation is located in Wuhan, which is a thoroughfare of nine provinces. It is the only military research institute specialized in ship electric propulsion equipment in China. It is mainly engaged in the research, development, design, testing and manufacturing of ship electric propulsion systems and equipment. .

Wuhan Nanhua Huanggang Jiangbei Shipbuilding Co., Ltd. was acquired by Wuhan Nanhua Express Ship Engineering Co., Ltd. and invested and transformed into a modern medium-sized shipbuilding enterprise.

This article focuses on the application of GGQ series high-pressure solid-state soft starters in 4 mixers of Lantian Paper. This article researches and combines engineering application practice to analyze the technical principles and characteristics of its GGQ series high-pressure solid-state soft starters. The application results show that, It can meet the individual needs of users for high-voltage soft-start devices, and has very important economic benefits and social value.

1. The role of blowers in petrochemical refining projects. In the petrochemical refining process, the relevant equipment needs air with a certain pressure and temperature for necessary process treatment during operation. To achieve this condition, the blower must be used for compression, so the blower system It is an important equipment component in the petrochemical oil refining production process, and the power of the motor that drives the blower is generally relatively large, and it is also one of the main electrical loads in the petrochemical industry.

AC asynchronous motors have been widely used in my country's coal mines, petroleum, chemical industry, steel, power generation, water supply, cement and building materials due to their simple structure, extremely high operational reliability, extremely strong environmental adaptability and excellent drag performance. . But the fatal disadvantage of AC asynchronous motors is that they have a large starting shock, which will have an adverse effect on the system.