Questions about a variable frequency pump
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This is an actual problem I'm having: The pump is a slurry pump with a variable frequency motor. The parameters marked on the pump's nameplate are consistent with the selection parameters. The water test is now being carried out. When the motor speed is adjusted to 70%, the current has reached the rated current. It is checked that there is no fault in the electrical part and the pump cranking is easy. Please tell me what causes this? I personally think it is possible that the impeller was mismatched during assembly by the manufacturer. But I think this is unlikely. Take it out and discuss it with everyone
If the current has reached the rated current, it means that the load has increased, so there should be no problem with the electrical appliances. However, I would like to ask whether you see the current on the inverter or on the ammeter. Only by ensuring that the two are consistent can it mean there is no error. If you read it correctly, ask the equipment whether the slurry pump can be tested with water.
The reason for the large current may be that the head of the pump is selected to be high. 2
1. The density of slurry is much smaller than that of water, 2. The diameter of the impeller is too large, 3. The motor and pump do not match, and a small horse pulls a large cart.
Because the medium is water, the density increases, which increases the motor current.
It may be because the head is small and the flow rate is too large.
The most likely reason is that the density of water is greater than the density of the actual medium, and the water test requirements were not considered when selecting the pump.