Reasons for high current in the forced circulation pump
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When the secondary forced circulation pump in the evaporation section of our plant is shut down, the current is 120A; however, after it was started up today, the current rose to 150A. The sound of the pump is normal, and its operation parameters are also normal. We asked an electrician to check the motor, and he replaced the motor’s bearings, but the current remained at 150A even after that. Could everyone help analyze what could be the cause? Thank you! The pump model is ZW600-80 (Xinda Pump Factory)
1. If the current value is read from the ammeter on the field control panel, it may be that the gauge there is faulty; it is best to verify this value with the current reading in the substation. 2. Check whether the outlet flow control valve has operated; as the flow rate increases according to the flow curve, the current also increases. 3. If possible, remove the coupling and rotate the motor alone to check its no-load current; if it exceeds 30% of the rated current, the motor should be repaired.
Minor cavitation may occur; this has also happened with one of the boiler feed pumps in our facility. Additionally, the current also depends on the pump’s flow rate and the work performed.
1. Check the ammeter； 2. Check whether the circulation return valve is opened wide when the pump is started ；
Thank you all for your help. I used a bearing film tester to check, and it seems there’s a problem with the bearing.