Abstract : This paper briefly describes the operation status of the gas blower, focuses on analyzing the causes and handling methods of frequency converter failure, and proposes suggestions for strengthening daily maintenance. Keywords : Producer gas; Frequency converter; Automatic shutdown; Rated voltage; Power grid fluctuation. The gas plant of Aluminum Corporation of China (Shanxi Branch) is a gas production unit that mainly produces producer gas and supplements it with coke oven gas. The producer gas and coke oven gas are mixed and supplied to the alumina roasting furnace of Shanxi Branch and for residential use. Residential gas is pressurized and delivered by a centrifugal blower of model D110-12 (30kW motor). In March 2003, the blower underwent frequency conversion speed regulation, with a JD-BP430 frequency converter controlling the gas blower to allow for reasonable adjustment during peak and off-peak periods of residential gas consumption, ensuring both meeting residential gas needs and saving energy. I. Fault Analysis and Handling At the end of 2003, the frequency converter experienced several automatic shutdown failures. Figure 1 shows the main circuit schematic diagram of the gas blower motor. When the gas blower first failed to shut down, an inspection of the main circuit revealed that the contactor supplying power to the frequency converter had disconnected, causing the frequency converter to lose power. Information from the plant's 6kV high-voltage substation indicated a significant fluctuation in the power grid at the time, which also caused several blowers and pumps without frequency converter speed control to automatically stop. Therefore, it was determined that the power grid fluctuation caused the frequency converter to lose power, leading to the blower shutdown. After restarting, the blower operated normally. A few days later, another automatic shutdown fault occurred. Investigation revealed that the contactor was closed, and the frequency converter displayed a low-voltage protection signal. At that time, no blowers or pumps in the entire plant were shut down. The low-voltage protection setting of the frequency converter was checked and found to be 85% of the rated voltage. Since the contactor's holding voltage is generally around 70% of the rated voltage, the initial judgment was that the power grid fluctuation, with the fluctuation value between 70% and 85% of the rated voltage, caused the frequency converter's protection to activate even though the contactor was not de-energized. After restarting, it operated normally. [b][align=center]For more details, please click: Analysis and Handling of Frequency Converter Blower Shutdown Faults[/align][/b]