In-depth understanding of the factors of motor overload during the use of corrosion-resistant pumps!
In the daily chemical industry, the use of corrosion-resistant pumps will present different problems and phenomena. We need to analyze and compare the different situations, and use the correct method to deal with them. Can the pump run at a reasonable operating point and the centrifugal pump run at a high efficiency point for a long time
In the daily chemical industry, the use of corrosion-resistant pumps will present different problems and phenomena. We need to analyze and compare the different situations, and use the correct method to deal with them. Only in this way can the pump run at a reasonable operating point and the centrifugal pump
run at a high efficiency point for a long time.
editor of the green ring
is here today to analyze the cause of motor overload (overcurrent) when using corrosion-resistant pumps;
The first thing to explain is that overcurrent is normal when the pump is started, and the current will drop to a normal level after the pump is running normally, no further treatment is required. In addition, if the outlet valve is fully opened when the pump starts, the motor will also overcurrent, so it is recommended to slowly open the outlet valve after turning on the power. Generally, the starting current of the motor can reach 5 to 6 times the rated current, which will not cause damage to the motor.
There are many reasons for the overload of the corrosion-resistant pump motor, and the treatment methods are different. The different reasons and their solutions are described in detail below:
(1). Pump selection problems: The pump has too much head lift and increased flow, which may cause the motor to be overloaded, the design parameters do not match the actual operating parameters, and the calculated shaft power does not take into account the specific gravity of the medium. Replace the pump or cutting impeller again, and replace the bigger motor;
(2) Bending of pump shaft: The pump shaft is bent or the rotor's radial runout is too large, the pump shaft or its sleeve and the guide vane friction, the impeller and the seal ring friction, causing excessive operating load. Straighten the bending of the shaft or replace the pump shaft;
(3). The outlet valve is fully opened when starting, the resistance in the outlet pipe is too small, the pump load is too large, and the small outlet valve is closed. Reduce the pump flow, which can ensure the head while reducing the current;
(4). The packing is too tight or the mechanical seal is skewed, the clearance of the sliding bearing is too small, and the compression is too large. Adjust the tightness of the packing and increase the clearance of the sliding bearing;
(5). The pump shaft is not concentric with the motor shaft. Readjust the concentricity between the pump and the motor shaft;
(6). The assembly is not good, friction, jamming or bearing burnout will cause serious damage. Replace bearings and reassemble;
(7). The motor speed is too large. Adjust the motor speed;
(8). The gap between the impeller and the pump casing is too small to produce friction. Adjust the clearance between the impeller and the casing to eliminate friction;
(9). The coupling clearance is too small. Adjust the clearance;
(10). The suction pipe is not smooth and the axial force is too large. Adjust the pipeline
(11). Liquid viscosity is higher than specified value. Change the viscosity of the pump or diluted liquid again, which meets the requirements of process transportation;
(12). The liquid is crystallized and the impeller is stuck. Clean up the foreign body in the pump cavity;
Sometimes maintenance workers can have problems when changing parts. In order to meet different flow rates, head parameters, and industrial and mining conditions, the same type of pump is usually equipped with multiple specifications of impellers and pump covers. When the small impeller is replaced with a large impeller, the motor will also cause overcurrent.
If you suspect that there is a quality problem with the motor itself, you can remove the motor and run it away from the pump head to see if the operation is normal. Or use a spare motor for replacement or find an electrician to test with professional equipment.
In summary, there are many reasons for the motor overload in the use of corrosion-resistant centrifugal pumps. To avoid motor overload, not only must it be reasonably selected during design, but also rely on the joint efforts of production units and users to avoid the above problems. This requires us to accumulate more experience in actual work. If an overload occurs, we should deal with it in time to ensure the safe and reliable operation of the centrifugal pump.
If all the above problems are ruled out and have not been resolved yet, please go to Green Ring Pump Industry and we will send professionals to help you solve them on the spot.