Keywords: frequency converter speed regulation flow energy saving analysis At present, many electric drive applications at home and abroad have widely applied vector control frequency converters to stepless speed regulation of AC motors in general machinery, textile, printing and dyeing, papermaking, steel rolling, chemical and other industries. Not only is the automatic speed regulation accuracy getting higher and higher, but it has also achieved obvious energy saving effect. Fan and water pump loads are square torque loads, the control requirements are simple, and the corresponding frequency converter price is also low, but its energy saving effect is particularly obvious. 1 Energy saving principle (1) The frequency converter controls the fan, which is a power saving method to reduce aerodynamics. Compared with the commonly used method of adjusting the damper to control the air volume, it has obvious power saving effect. In Figure 1, curve (1) is the air pressure-air volume (HQ) characteristic of the fan at a constant speed n[sub]1[/sub], and curve (2) is the network air resistance characteristic (damper fully open). Assuming the fan operates at its most efficient point A, the air pressure is H2, the air volume is Q1, and the shaft power N1 is proportional to the product of Q1 and H2, which can be represented by the area H2OQ1 in the diagram. If the production process requires the air volume to be reduced from Q1 to Q2, adjusting the damper is equivalent to increasing the pipe network resistance, causing the pipe network resistance characteristic to change to curve (3), and the system changes from the original operating point A to the new operating point B. As can be seen from the diagram, the air pressure increases instead, and the shaft power is proportional to the area BH1OQ2. Obviously, the shaft power decreases only slightly. [b][align=center]For details, please click: Application and Energy-Saving Analysis of Frequency Converters in Boiler Fans and Water Pumps[/align][/b]