Reasons for excessive current in mechanical pumps.
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This post was last edited by David3kkk on 2019-4-13 at 14:20. There is a pump with a rated flow rate of 219 m3/h; the density of the fluid it handles is around 0.85–0.87 g/cm3. The actual flow rate is about 130 T/h, and the pump often experiences overcurrent. What could be the reason for this?
Can the reason be analyzed by expressing it this way? What if the medium transported by this pump originally had a specific gravity of around 0.5? Please send the parameters of the pump, such as head, pump efficiency, motor power, etc
Does the vibration not exceed the limit? Vibration overcurrent over
Head: 113 m, inlet pressure: 0.3 MPa, outlet pressure: 1.2 MPa, operating temperature: 120 degrees Celsius, motor rated power: 90 KW, speed: 2950 rpm, rated current: 161.7 A
The rated flow rate is 200 cubic meters; with a sealing efficiency of 0.8, the output is 160 tons per hour. The head is 110 meters, and with an inlet pressure of 3 kilograms per square meter, the pressure reaches 140 meters. The current outlet pressure is 12 kilograms per square meter, so the current level should not exceed the normal limit. If there is an overcurrent at this time, three pieces of data need to be checked: first, whether your traffic is ready. Second is whether the pressure is accurate. Third, which company manufactured the pump, what is its model, and what is its efficiency? This of yours might be related to the pump.
Specific gravity is 0.85; there is no issue with the pressure difference between inlet and outlet
If there is no mechanical friction, then it points to the pump’s efficiency – perhaps the gap around the mouth ring is too large, resulting in excessive backflow and thus a decrease in the pump’s efficiency.
The selection of a pump is very important. If, for your parameters, the pump is already operating at a low head and high flow rate, resulting in low efficiency, then if the pressure at the pump’s outlet should be 14 kilograms but it is actually 12 kilograms, this represents a severe deviation from the optimal operating conditions. It is normal for the pump efficiency to decline and for the motor to experience overcurrent. If I wasn’t clear, we can chat privately.
P = density × g × H = 850 * 9.81 * 113 = 0.94 MPa; adding the inlet pressure of 0.3 gives around 1.2
Is the head of a water pump generated by centrifugal force, and is it also related to density? This is beyond my knowledge.