Abstract : This article takes the Mitsubishi FR-S500 frequency converter as an example to introduce its application in a refrigerator production line. Specifically, based on the basic principles of motor speed control, a brief introduction to the engineering design of an automated production test line in a refrigerator factory is given. Practice shows that the use of the FR-S500 frequency converter is effective and can achieve certain economic benefits. Keywords : Frequency converter, Mitsubishi FR-S500 1 Introduction With the advancement of science and technology and the improvement of production efficiency, China's production technology has long since developed from small-scale workshop-style manual labor to mechanization, automation, and intelligence. Starting in the 1960s, due to the development of light industry, mechanized and automated production lines first appeared in the bicycle manufacturing industry. Now, assembly line production technology is applied in many fields. Taking Xingxing Refrigeration Equipment as an example, with the development of the company, its refrigerator production line has also gone through the development process from fully manual production to semi-automated assembly line production and the current fully automated assembly line production. The author participated in the design and construction of an automated assembly line. Below, we briefly introduce the application of Mitsubishi frequency converters in motor speed control of assembly lines. 2. Project Overview As shown in Figure 1, this automated production line is a circular structure. 100 trolleys are placed on the circular guide rail, and the trolleys move along the rail via a traction chain. The requirement is that the trolleys complete one rotation in 45 minutes to 2 hours, which must be manually and continuously operable. This necessitates consideration of production line speed control. After consideration, it was decided to use an electric motor as the power source for the production line's movement. In the field of electric motor speed control, there are two commonly used methods: DC motor manufacturing and AC variable frequency speed control. DC motor speed control has long held a dominant position in the traditional speed control field due to its advantages of rapid forward and reverse rotation, large starting torque, fast braking, accurate stopping, wide speed range, high precision, and fast response. However, its large size and weight, and the significant maintenance work, also bring many inconveniences to its use. With the development of power electronics technology, computer technology, and automatic control technology, and the reduction in the cost of AC variable frequency speed control, AC variable frequency speed control has become the main development direction of modern electrical drives, replacing DC speed control. [b][align=center]For details, please click: Application of Frequency Converters in Refrigerator Production Lines[/align][/b]