Power saving with the inverter
Some literature claims that the frequency converter is a power-saving control product, giving the impression that power can be saved by using the inverter.
In fact, the reason why the inverter can save electricity is because it can regulate the motor. If the inverter is a power-saving control product, then all the speed control equipment can also be said to be a power-saving control product. The inverter is only slightly higher in efficiency and power factor than other speed control devices.
Whether the inverter can achieve power saving is determined by the speed regulation characteristics of its load. For loads such as centrifugal fans and centrifugal pumps, the torque is proportional to the square of the speed, and the power is proportional to the cube of the speed. As long as the original valve is used to control the flow, and it is not working at full load, it can be saved to speed control. When the speed drops to 80% of the original, the power is only 51.2% of the original. It can be seen that the application of the frequency converter in this type of load has the most obvious power saving effect.
For loads such as Roots blowers, the torque is independent of the magnitude of the speed, ie the constant torque load. If the air volume is adjusted by using the venting valve to remove the excess air volume, and the speed control operation is changed, the power saving can also be realized. When the speed drops to 80% of the original, the power is 80% of the original. It is much less efficient than the application in centrifugal fans and centrifugal pumps. For constant power loads, the power is independent of the magnitude of the speed.
