Application of frequency converters in fans and water pumps

Why can frequency converters save power when applied to fans and water pumps

The relationship between the air volume, air pressure, shaft power of the fan and the flow rate, head, and shaft power of the water pump follows the following formula:

               Q ∝ N

               H ∝ N²

               P ∝ N³

Q: Air volume, flow rate

H: wind pressure, head

P: shaft power

N: rotational speed

Taking a water pump as an example, according to the similarity law of the water pump, it can be concluded that:
 

               Q1 / Q = N1 / N              （1）

               H1 / H = （ N 1 / N ）²       （2）

               P1 / P = （ N 1 / N ）³       （3）

               P1 = P（N1 / N ）³            （4）

For example, when the frequency drops from 50 Hz to 45 Hz, the power decreases
              ［1－（45/50）³］=27.1 %
When the frequency drops from 50 Hz to 40 Hz, the power decreases
              [1－（40/50）³]=48.8 %

From this, it can be seen that the energy-saving effect of frequency converters used on fans and water pumps is very significant. Generally, the power saving rate can reach over 30%. 

The benefits of applying frequency converters to fans and water pumps

The application of frequency converters in fans and water pumps not only significantly saves electricity, but also has direct economic benefits and obvious indirect benefits:
① The lifespan of the pump is extended, and the amount of maintenance is reduced.
After adopting frequency conversion speed regulation, the speed of the pump generally decreases, the wear of mechanical components such as bearings is reduced, the phenomenon of pump suction can be avoided, the seal of the pump end face is not easily damaged, the number of pump failures is reduced, the service life is extended, and the maintenance amount is correspondingly reduced.
② Fast response speed, high accuracy, and easy control.
The acceleration and deceleration time of variable frequency speed regulation can be adjusted according to process requirements at any time, with a wide speed regulation range, high accuracy, hard mechanical characteristics, good speed regulation performance, and can meet strict process requirements. The control quality is higher than that of regulating valves.
③ Reduced starting current and improved electrical protection quality.
After using the frequency converter, the motor can be soft started, and the starting current can be reduced from about 6 times to below 1.7 times, while the starting torque does not decrease, and can even be increased. Therefore, the impact on the motor and power grid has significantly decreased, the start-up voltage drop has decreased, and the capacity requirements for the power grid have decreased.
④ Easy installation and maintenance
The frequency converter has a small volume, fewer vulnerable parts, and is easy to maintain.

Conclusion

Recommended selection for fan and water pump frequency converters: FST-500 series, FST-610 series, FST-650L series/FST-650S series. If you have any questions, please contact our online customer service, and we will be happy to serve you