Abstract: This paper introduces the application of frequency converters in anode multi-functional overhead cranes and conducts a preliminary analysis of the problems encountered in design and use, hoping to provide assistance for future design and maintenance. Keywords : Frequency converter; Multi-functional overhead crane; Variable frequency speed control Anode multi-functional overhead cranes require stable operation, precise positioning, smooth speed control characteristics, flexible operation, and ease of use. This type of equipment was introduced by Japan Light Metals Co., Ltd. in the late 1970s. The speed control method of the equipment adopts a staged coarse adjustment of the rotor series resistance of a wound-rotor motor. The stator uses a thyristor regulating circuit for voltage adjustment, and the two are used together to achieve the purpose of fine speed adjustment. Due to the influence of the operating environment of anode multi-functional overhead cranes, this speed control method has shortcomings such as high failure rate and large maintenance workload. From the speed control principle itself, it can be seen that this speed control method has the disadvantage of large energy loss. At the same time, the speed control characteristics are not ideal, especially the torque characteristics are relatively soft at low speeds. How to solve these shortcomings? Using a variable frequency speed controller is a bold and feasible idea. Through several years of practice and improvement, it has been proven that the use of this technology on large overhead cranes is completely feasible, achieving the final goal and obtaining good economic benefits. 1. Introduction to the Main Circuit of the Variable Frequency Speed ​​Controller The anode multi-functional overhead crane itself weighs 184.5 t, and the total weight reaches nearly 200 t when loaded (feeding, dust collection, and lifting parts). The design uses dual motors to drive the main trolley and one motor to drive the auxiliary trolley, with a total inverter drive power of 75 kW. The main trolley and auxiliary trolley are each controlled by one inverter, with motors powered by 30 x 2 kW and 15 kW respectively. This system utilizes the inverter's external control terminals, with a manual controller installed in the control room to achieve forward and reverse rotation of the main and auxiliary trolleys. The inverter's multi-frequency setting function enables graded speed regulation, and the inverter controller's acceleration/deceleration time characteristics and automatic speed tracking function ensure smooth speed transitions between stages. Because normal equipment start-up, stopping, forward/reverse rotation, and speed regulation are performed directly in the control room, the system achieves stable operation, precise positioning, and convenient operation. Based on the usage and load requirements of the frequency converter, an AC reactor and a braking resistor are also configured around the frequency converter to ensure the operating conditions of the frequency converter and fully meet the requirements of the production process. [b][align=center]For details, please click: Application of Frequency Converters in Anode Multifunctional Overhead Cranes[/align][/b]