Centrifugal pump with Freq. converter

[Fritzfrederix]

Hi,

We've have a discussion about a centrifugal pump which is driven by an Frequency converter. I believe that your frequency converter only can use a small part of your pumpcurve. My collegue is saying that you can use the full scale off the pump. In other words you can use from 10 to 60 Hz of your frequency converter.
Anyone who can slove our discussion?

Thanks Rudi

 

[DesignerMike]

Actually, I have used an Inverter to overspeed the pump (say 70hz) extending the curve and increase pressure....Not EVERY pump will handle this, so make sure you check with the factory before you break something.

You can easily use 10-60 hz, BUT since a centrifugal is not positive displacement, the flow and pressure will not be a linear relationship to the frequency. Depending on the pump, I doubt you would get very much flow at all if you run below 25 hz.
Typically my customers have used an inverter to help control line velocity in a loop where they have variable use points. If there is heavy usage, the control system increases pump speed (and adjusts control valves) to keep the recirculating velocity up and pressure constant.