Motor vibration is an important index to evaluate the reliability of the operation of the alkali liquid transfer pump unit. So what harm will the motor vibration bring to the lye transfer pump, and how to solve it?
The vibration of the motor will shorten the life of the winding edge and the bearing, and affect the normal lubrication of the sliding bearing. The vibration force promotes the expansion of the edge gap, so that external dust and moisture invade it, resulting in a decrease in edge resistance and an increase in leakage current, and even edge breakdown Wait for the accident. In addition, the vibration of the motor will easily cause the water pipe of the cooler to vibrate, and the welding point will vibrate. At the same time, it will cause damage to the load machinery, reduce the accuracy of the workpiece, cause fatigue of all mechanical parts subject to vibration, and loosen the anchor screws. Or broken, the motor will cause abnormal wear of the carbon brushes and slip rings, and even serious brushing and burning of the green side of the collector ring. The motor will produce a lot of noise. This situation usually occurs in DC motors. occur.
There are many reasons for motor vibration. Motors with more than 8 poles and large number of poles will not cause vibration due to quality problems in motor manufacturing. Vibration is common in 2--6 pole motors. GB10068-2000, "Rotating Motor Vibration Limits and Test Methods" stipulates the vibration limits, measurement methods and rigid foundation criteria for motors with different center heights on the basis of rigidity. Standard can judge whether the motor meets the standard
1. Rotor, coupler, coupling, transmission wheel (brake wheel) caused by imbalance
2. The iron core bracket is loose, the oblique key, the pin is invalid and loose, and the rotor is not tightly bound will cause the rotating part to be unbalanced.
3. The shaft system of the linkage part is not centered, the center line does not coincide, and the centering is incorrect. This kind of failure is mainly caused by poor alignment and improper installation during the installation process.
4. The center line of the linkage part coincides in the cold state, but after a period of operation, due to the deformation of the rotor fulcrum and foundation, the center line is destroyed again, and vibration occurs.
5. The gears and couplings connected to the motor are faulty, the gears are badly engaged, the gear teeth are worn out, the lubrication of the gears is not good, the coupling is skewed, misaligned, the gear coupling tooth profile, tooth pitch is wrong, the gap is too large Large or severe wear will cause certain vibration (public account: pump housekeeper).
6. Defects in the structure of the motor itself, the shaft journal is elliptical, the rotating shaft is bent, the gap between the shaft and the bearing bush is too large or too small, the rigidity of the bearing seat, foundation plate, certain part of the foundation and even the entire motor installation foundation is insufficient.
7. Installation problems, the motor and the base plate are not firmly fixed, the foot bolts are loose, and the bearing seat and the base plate are loose.
8. The gap between the shaft and the bearing bush is too large or too small can not only cause vibration, but also cause the lubrication and temperature of the bearing bush to produce abnormal motor-driven load conduction vibration, for example
9. The fan and the lye transfer pump driven by the motor vibrate, causing the motor to vibrate.
10. Stator wiring error of AC motor, short circuit of rotor winding of winding type asynchronous motor, short circuit of excitation winding of synchronous motor, wrong connection of excitation coil of synchronous motor, broken bar of cage asynchronous motor, rotor core deformation, resulting in the air gap between stator and rotor Averaging, resulting in unbalanced air gap magnetic flux and causing vibration
plan to overhaul the cause of the failure
1. The maintenance of electrical reasons is to determine whether the three-phase DC resistance of the stator is balanced. If it is unbalanced, it means that there is open welding in the welding part of the stator connection. Disconnect the winding phase to find out. In addition, whether there is a short circuit between the windings. If the fault is obvious, you can see the burnt marks from the edge surface, or measure the stator winding with an instrument, confirm the short circuit between the turns, and then re-off the motor winding
For example: an alkali-resistant pump motor. The motor not only vibrates during operation, but the bearing temperature is too high. A minor repair test found that the DC resistance of the motor is unqualified, and the stator winding of the motor is open welding. After the fault is found and eliminated, the motor runs normally.
2. Maintenance of mechanical causes
Check whether the air gap is uniform, if the measured value exceeds the standard, readjust the air gap. Check the bearing, measure the bearing clearance, if it is unqualified, replace with a new bearing, check the deformation and looseness of the iron core, the loose iron core can be glued and filled with epoxy resin, check the shaft, repair the curved shaft, re-work or directly Straight shaft, and then do a balance test on the rotor. During the trial operation after the blower motor was overhauled, the motor not only vibrated greatly, but the temperature of the bearing bush exceeded the standard. After several days of continuous treatment, the fault remained unresolved. My team members found that the air gap of the motor was very large and the tile seat level was not up to standard. After finding the cause of the fault, after re-adjusting the gaps of various parts, the motor was successfully tested.
3. The inspection of the load mechanical part is normal, and the motor itself has no problem. The cause of the failure is the connection part. At this time, check the basic horizontal plane, inclination, strength, center alignment of the motor and whether the coupling is damaged. Whether the motor shaft extension winding meets the requirements, etc.
