Centrifugal pump flow rate issues
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A new DFW series centrifugal pump from Shangfang Dongfang has been installed on site. Flow rate: 300 m3/h, head: 20 m, motor power: 45 KW, inlet and outlet diameter: 200 mm. The medium transported is salad oil. Driven by ABB’s ACS series frequency converters. When the frequency is set to 50HZ and the rotational speed is 1480 r/min, the maximum flow rate is only around 150 m3. At this point, the output power of the inverter is approximately 20 KW, with a current of 40–48 A; beyond this, the flow rate cannot be increased any further. The pump inlet is only a little over 1 meter away from the oil tank, and the oil tank is located above the pump inlet. The outlet pipeline is about 5 meters high at its highest point and approximately 300 meters in length. The exit is basically open, leading directly into the cabin.
There must be a problem with the installation or purchase of the inverter; the viscosity of the salad oil is quite high
What is the pump outlet pressure? Are there fluctuations in pressure?
The frequency converter is 55KW, and the maximum pressure at the pump outlet is a little over 2 kilograms.
Is it because the viscosity of your medium is too high, causing the pump to run at a lower speed and thus reducing the centrifugal force generated?
The inverter is now operating at line frequency; could you tell me what the problems are? Why is the current so low? Is it because the load is low and the pump can’t deliver enough flow that you start to suspect the motor inverter? There’s a problem with this logic
Please tell me the logic behind the problem with the inverter
I think it’s still necessary to look for the cause in your system. After doing some calculations regarding the resistance in the outlet pipeline, it seems that a head of 20 meters isn’t sufficient (you should verify this based on the actual conditions at your site); as a result, the pump operates at a point on the left side of its operating range, which prevents an increase in flow rate.