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Steps to deal with motor vibration

1. Disconnect the motor from the load, test the motor empty, and check the vibration value.

 

2.Check the vibration value of the motor foot.According to the national standard GB10068-2006, the vibration value of the foot plate should not be greater than 25% of the corresponding position of the bearing. If it exceeds this value, the motor foundation is not a rigid foundation.

 

3. If there is only one or two diagonal vibrations exceeding the standard on the four feet, loosen the anchor bolts, the vibration will be qualified, indicating that the foot pads are not solid enough, and the anchor bolts will cause the machine base to deform and vibrate after tightening. Cushion the feet firmly, re-align them, and tighten the anchor bolts.

 

4. Fully tighten the four anchor bolts on the foundation, and the vibration value of the motor still exceeds the standard. At this time, check whether the coupling on the shaft extension is level with the shaft shoulder. If it is not flat, the excess key on the shaft extension is caused Exciting force will cause the motor's horizontal vibration to exceed the standard.

 

In this case, the vibration value will not exceed too much, and the vibration value can often decrease after docking with the host. The user should be persuaded to use it. The two-pole motor is installed in the shaft extension keyway according to GB10068-2006 in the half key during the factory test. The extra keys will not increase the excitation force. If you need to deal with it, just cut off the extra keys to make them longer.

 

5. If the air test vibration of the motor does not exceed the standard, and will vibrate & exceed the standard when loading.There are two reasons: one is that the alignment deviation is large;

The other is that the residual unbalance of the rotating parts (rotor) of the main engine overlaps with the residual unbalance of the motor rotor. After docking, the residual unbalance of the entire shaft system at the same position is large, and the generated vibration force is large, causing vibration . At this time, you can disengage the coupling, rotate either of the two couplings by 180°C, and then dock the test machine, the vibration will decrease.

 

6. The vibration speed (intensity) does not exceed the standard, and the vibration acceleration exceeds the standard. Only the bearing can be replaced.

 

7. Due to the poor rigidity of the rotor of the two-pole motor, the rotor will be deformed when it is not used for a long time, and it may vibrate when it is turned again. This is the reason for the improper storage of the motor. Under normal circumstances, the two-pole motor is in storage. The motor should be cranked every 15 days, and the motor should be rotated at least 8 laps each time.

 

8. The motor vibration of the sliding bearing is related to the assembly quality of the bearing bush. Check whether the bearing bush has a high point, whether the bearing bush has enough oil, the bearing bush tightness, the bearing bush clearance, and the magnetic center line are suitable.

 

9. Under normal circumstances, the cause of motor vibration can be simply judged from the vibration values in three directions. The horizontal vibration is large, the rotor is unbalanced; the vertical vibration is large, and the installation foundation is not good; the axial vibration is large, and the bearing assembly is with low quality.

 

This is just a simple judgment. It is necessary to find the true cause of the vibration based on the site conditions and the above-mentioned factors.

 

10. Special attention should be paid to the axial vibration of the Y series box-type motor. If the axial vibration is greater than the radial vibration, it will cause great harm to the motor bearing and cause a shaft holding accident.

 

Pay attention to the bearing temperature. If the locating bearing heats up faster than the non-locating bearing, the machine should be shut down immediately. This is because of axial vibration caused by insufficient axial rigidity of the machine base, so the machine base should be reinforced.

 

11. After the rotor is dynamically balanced, the residual imbalance of the rotor has been solidified on the rotor and will not change. The vibration of the motor itself will not change with the change of location and working conditions. The vibration problem can be dealt with at the user site. of.

 

Under normal circumstances, it is not necessary to perform dynamic balance verification on the motor for maintenance. Except for very special conditions, such as flexible foundation and rotor deformation, etc., it must be dynamically balanced or returned to the factory to check.

 

Reported by Jessica


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