Abstract : A C6141 lathe was assembled using a Siemens SINUMERIK 802S CNC system and frequency converter, and twenty common fault points were set. The structure of the CNC system, the design of the electrical control system, and the setting of electrical fault points are introduced. Keywords : lathe, frequency converter, electrical fault point [b]1 Introduction[/b] With economic development and accelerated industrialization, the manufacturing industry is gradually shifting from labor-intensive to technology-intensive. Its main characteristics are a large increase in imported advanced equipment and the vigorous development of modern basic machinery represented by CNC machine tools. The research, development, and application of CNC machine tools play an extremely important role in improving labor productivity and product quality, enhancing adaptability and competitiveness in a dynamic and ever-changing market, and changing the backward state of China's manufacturing technology. Vigorously developing advanced manufacturing technology with CNC technology as its core has become an important way for countries around the world to accelerate economic development, improve comprehensive national strength, and enhance national status. Nantong Textile Vocational and Technical College, as a higher vocational and technical college, is employment-oriented and cultivates technical application-oriented talents for production, construction, management, and service. To adapt to the adjustment of the manufacturing industry structure and meet the social demand for CNC machining and CNC technology applications, the college established a CNC Technology Application major in 2002. The curriculum for this major includes courses such as "CNC Technology," "CNC Machine Tool Fault Diagnosis and Repair," and "CNC Machine Tool Electrical Control," along with two weeks of practical training in CNC machine tool fault diagnosis. The college's existing CNC equipment is either dedicated to teaching, limited to operation and programming instruction with some restricted functions, or general-purpose production equipment lacking the ability to diagnose and repair common faults. The dual-purpose production and teaching CNC lathe, based on a standard CNC lathe, incorporates common electrical fault points; the electrical box and control box are semi-transparent (with glass windows). The open structure allows students to observe the entire CNC device safely (with the electrical box door and control panel back cover closed) and understand the interconnections. During fault diagnosis training, observing the energizing and de-energizing states of contactors and relays through the glass window greatly aids in fault diagnosis and troubleshooting. Therefore, this dual-purpose production and teaching CNC lathe organically combines practical training with production. During training, it can be used for understanding and training in CNC machine tool structure, CNC system composition, CNC machine tool operation, programming, CNC machining processes, and common electrical fault diagnosis and repair. During production, it is suitable for single-piece or small-batch turning of external diameters, internal diameters, end faces, threads, and shaped surfaces, offering high production efficiency, high machining accuracy, and stable and reliable quality. The development of this dual-purpose production and teaching CNC lathe not only improves CNC technology training conditions but also allows for turning operations outside of training, creating certain economic benefits. [b][align=center]For more details, please click: Application of Frequency Converters in the Development of Dual-Purpose Production and Teaching CNC Lathe[/align][/b]