Can changing the frequency of a computerized pump save electricity, and by how much?

If it can’t be calculated, why? What other data is needed?

The design institute advises that once the pump’s head and flow rate are determined, its efficiency is generally also fixed. Once all these parameters are set, the shaft power is determined as well; and once the shaft power is known, no changes can be made to save energy. P=QgHρ/efficiency; P=1.732*UICOSφ, and it can be seen that the two formulas are identical. The main purpose of up-converting the frequency is that, if the operating conditions of the pump change frequently – for example, when a higher head or flow rate isn’t required – it is possible to reduce the frequency. The shaft power at the new flow rate and head obtained by using frequency reduction methods is more energy-efficient than when there is no frequency conversion, as in the case of using a throttle valve. Summary: I’m not sure if you understand with this explanation. Frequency conversion is only applicable to variable operating conditions.

Whether frequency conversion is needed mainly depends on your usage conditions. If the production load needs to be changed, variable frequency drive is the preferred option. If constant production conditions require it, a suitable matching pump must be replaced. No calculation is needed for this.

Agree with what was said above: unless your operating conditions are complex and variable, and the load can handle it, it’s not advisable to make changes just because you think it will save electricity. Learn about grid disturbances and phase differences – it would be interesting if a large chemical plant lost power all at once and ended up in MFT mode. The medium inside the reaction vessels would be wasted, and the owner might even consider throwing you into those vessels as punishment.

Under the same actual operating conditions, 22 cubic meters are still required. It is recommended to use a cut impeller whenever it is possible to reduce the head; by changing the diameter of the impeller, the head can be lowered along with the flow rate. According to the impeller cutting principle, given the minimum head you are willing to accept, the diameter of the impeller after cutting can be calculated. With this diameter known, the flow rate at that head level can be determined using the same principle, and the shaft power required for that impeller diameter can also be calculated in this way. Then, the power of the motor required is calculated based on its safety factor. In this way, the maximum power consumption after cutting is determined. By using Ohm’s law and the actual operating current, the actual power consumption can be calculated; by comparing this with the previous operating current, it is possible to determine how much power has been saved. Don’t buy an inverter, and don’t switch to Xincheng either; it’s better to keep that money to buy meat. This is just for reference.

The pump you’re using is inefficient in itself; it doesn’t matter what motor you replace it with. Replace the pump; for this kind of water pumping operation, an 18.5kw motor is sufficient

The pump you’re using is inefficient in itself; it doesn’t matter what motor you replace it with. Replace the pump; for this kind of water pumping operation, an 18.5kw motor is sufficient

It is recommended to replace the pump in order to improve its efficiency; on this basis, frequency conversion can be applied, with further adjustments made according to the actual production requirements. Using a low-efficiency pump for frequency upconversion is merely a form of psychological comfort, and it is not a viable approach. Try a different pump; maybe 15 kilowatts will be enough.