Analyze shielded pump failures
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This post was last edited by WQC on 2015-7-27 at 11:38. Today, a centrifugal pump was started up; the medium transported by this pump is phenol. When the pump is first started, the pressure at its outlet reaches normal levels, but within a few seconds the pressure drops to zero. The voltage display in the MCC room’s distribution panel shows overvoltage and imbalance alarms. Could an expert analyze the possible reasons? 、
Possible reasons: 1. Bearing wear. 2. Motor reverses direction. 3. High motor load. 4. There are impurities inside the pump
There are many reasons, and the situations you mentioned are generally caused by the following factors: 1. The inlet filter is clogged, causing the material to vaporize inside the pump; this leads to an imbalance in axial forces, resulting in overload of the pump； 2. Incomplete filling of the pump, air present inside the pump, and unbalanced axial forces lead to pump overload ； 3. Bearing wear, causing the pump to overload ； 4. Ultimately, it is caused by an imbalance in axial forces. Please refer to the original poster.
The analysis makes sense, but our company simply replaced the pump.
That means there must be a problem with the pump; check whether any of its components are damaged.
The main issues I encountered were a loose impeller lock nut, the entry of contaminants (I wonder if phenol itself can crystallize at low temperatures), and bearing wear. The person who posted this question should check these aspects; once they’ve made the repairs, they should let me know the reasons
Phenol will clump at low temperatures; high temperatures in summer rule out this possibility. It’s bearing wear.
Check the bearings and thrust discs! ! ! ! ! ! ! ! ! ! !
The last edit to this post was made by zxf760718 on 2016-3-4 at 09:32. The three resistances of the motor are definitely unbalanced, which means the motor is damaged; replacing the motor coils will solve the problem