Abstract: Circulating water pump motors often adopt a fixed speed design, and their design flow rates often do not match actual demand,making it difficult for them to dynamically adapt to load or seasonal temperature changes. This is particularly true for circulating water pump motors in thermal power plants in Northeast China, due to significant seasonal temperature differences, operate for extended periods at conditions below the design water supply capacity, often resulting in deviations from the high-efficiency zone and significant energy waste. A double-speed transformation was conducted on a circulating water pump motor in a large thermal power plant in Northeast China. The reasons for choosing a double-speed transformation for the circulating water pump motor were analyzed, and the equipment operation mode and design parameters were elaborated. The key points and measures of the retrofit were provided, and the number of poles of the motor was changed to adjust the revolutions of the circulating water pump according to seasonal temperature changes. Practical application shows that the retrofitted circulating water pump motor now has dual options for speed selection, further enhancing the diversity and flexibility of the regulation mode of the entire circulating water system. Compared to before the retrofit, significant energy-saving effects have been achieved.

    Key words: electric motor; circulating water pump; thermal power plant; double-speed transformation; energy saving