1. Motor over current
Causes
(1)The head of pump is higher than the actual head of pipe.
(2) Friction between the impeller and the backplate.
(3) Low efficiency of motor
(4) Bearing broke down
(5) Non-concentricity of shaft and motor
Solutions:
(1) Make the head low of pump or turn down the valve of outlet.
(2) Adjust the direction of the impeller to make it well.
(3) Replace with a high one.
(4) Replace with a new bearing.
(5) Adjust the concentricity of the two shafts.
2. No-work when pump-start
Causes
(1) Non-remove the air in pump
(2) Suction piping system intakes.
(3) Air inflow into the shaft seal.
(4) Blocked of suction piping system or impeller
Solutions
(1). Increase breathing measurement.
(2). Overcome intake reason.
(3). Adjust the performance of packing seal to ensure the yield and pressure of the water seal.
(4). Eliminate the block.
3. Low head of pump
Causes
(1) Lower head of pump than the actual head of pipe
(2) Lower NPSH of pipe than the must NPSH of pump.
(3) The inlet valve of pump is not open or the valve is broke down
(4) Suction piping system intakes
(5) Suction piping system or the impeller blocked.
(6) High density of slurry.
Solutions
(1) Improve the head of the pump.
(2) Adjust the pipe equipment and make the Pipe NPSH is bigger than the pumps. Or to replace with a pump which can meet the NPSH requirement of pipe.
(3) Open the valve and replace with a new one.
(4) Overcome the intake reason.
(5) Eliminate the block.
(6) Make the density low or replace with a big pump of large bore.
4. Oscillation and the loud noise
Causes
(1) Unstable install of the pump or the pipe.
(2) Pump is working under the cavitations condition.
(3) Non-concentricity of pump and motor
(4) Unbalance of the impeller and the coupler is out of tolerance..
(5) Coupler elastic cushion broke.
(6) Bearing broke.
(7) Short supply of slurry
(8) Mismatching of pipe and pump
(9) Block of suction pipe or the impeller,
(10) Air pocket in some part.
Solutions
(1) Make it tight.
(2) Adjust the performance of pump and pipe to make the NPSH is bigger than the must one of pump.
(3) Adjust the concentricity of the two shafts.
(4) Make them balance
(5) Replace with a new one.
(6) Replace a new one.
(7) Increase the quantity of slurry or turn down the valve of outlet.
(8) Adjust the pump to match the pipe.
(9) Get rid of block.
(10) Add air evacuation value where the air pocket exists.
(11) There are many reasons to cause the shake or noise, please solve according to the actual working condition.
5. Slurry leak of shaft seal
Causes
(1) No seal water or the small pressure of seal water.
(2) Packing is not tight or installed incorrectly.
(3) Packing broken.
(4) Worn down heavily of shaft sleeve
(5) Unqualified machinery seal
Solutions
(1) Increase seal water or its pressure.
(2) Adjust the packing to meet the sealing property, and install the packing with 4-5 pieces.
(3) Replace it.
(4) Replace it.
(5) Reinstall.
6. Grease leak of bearing assembly
Cause
(1) Too much oil.
(2) Uninstalled well of bear gland seal.
(3) Oil leak of the pointer.
Solutions
(1) Add oil to the position of indication.
(2) Install it correct.
(3) Install the oil pointer.
7. Over hot of bearing
Causes
(1) Mismatching of pump and pipe and shake, evacuation or cavitations.
(2) Non-concentricity of shaft and motor
(3) Coupler elastic cushion broke
(4) Dirty grease or chamber intake slurry
(5) Bearing assembly broke or abrasive heavy
Solutions
(1) Adjust the pump and pipe
(2) Adjust the concentricity of the two shafts.
(3) Replace with a new one.
(4) Replace with new grease and keep the slurry form the chamber.
(5) Replace with a new bearing or wash the chamber.
