It is necessary to follow scientific diagnostic methods and diagnostic techniques when dealing with the vibration of the motor. Since the actual vibration fault is generally comprehensive and complex, it is difficult to analyze and process it. Therefore, when dealing with vibration faults, it is necessary to clear the mind and find out the specific cause of the vibration so that it can be targeted. Ground handling to minimize equipment downtime or damage caused by vibration.

One,
Harm of motor vibration
For most mechanical equipment, vibration is a common phenomenon in the operation of equipment. The motor is basically the same as some other equipment, and different degrees of vibration occur during operation. After long-term observation by relevant technical personnel, the hazards of motor vibration are obtained, and the hazards can be summarized as follows:
1) The vibration of the motor will consume energy to a certain extent, thereby reducing the efficiency of the motor;
2) The vibration will directly damage the bearing of the motor and accelerate the wear of the motor bearing, so that its normal life is greatly reduced;
3) The rotor of the motor is bent or broken, mainly because the looseness of the magnetic pole of the rotor causes the stator and the rotor to rub each other;
4) Vibration will reduce the insulation resistance to a certain extent, mainly because the vibration of the motor will cause the end of the motor to loosen the wire, causing the end windings to rub against each other;
5) Vibration will cause some parts to loosen, making other mechanical equipment unable to operate normally.
Second, the motor vibration causes and treatment methods 1 motor chassis vibration main causes and treatment methods
The main reason for the vibration of the motor frame in actual work can be summarized as follows:
1) the exciting force generated when the rotor vibrates;
2) The electromagnetic vibration generated by the stator core causes the frequency doubling vibration of the machine base. Relevant research shows that when the single unit capacity increases, the frequency doubling vibration will be more obvious. The conclusions obtained by the skilled person indicate that the bearing form of the bearing seat on the end cover of the stator frame has a much greater influence on the frame than the rotor excitation force in the form of a floor bearing.

The specific damping measures for the vibration of the motor frame are as follows:
1) setting the elastic structure, that is, changing the connection structure between the iron core and the base to the elastic structure, so as to reduce the influence of vibration to a certain extent;
2) Control the natural frequency of the base itself to avoid the frequency doubled vibration frequency of the core and the vibration frequency of the rotor.

2 Vibration caused by rotor imbalance and treatment method
The mechanical imbalance of the rotor in the motor can be roughly divided into three types:
1) Static imbalance, the centrifugal force caused by it will produce equal and identical vibrations on the two supports;
2) Dynamic imbalance, the centrifugal force generated by it will produce equal and opposite phase vibrations on the two supports;
3) Mixing imbalance, which is the most common mechanical imbalance encountered in the actual operation of the motor. The mixed unbalance is a vibration of different sizes and phases produced by the static unbalanced centrifugal couple and the dynamic unbalance couple acting on the two supports.

The treatment methods for the vibration generated by the rotor imbalance are:
1) The basic principle of dynamic balance check is used to process, that is, the vibration position caused by the unbalanced mass when the rotor rotates to find the specific position and size of the rotor imbalance, and then use the method of weighting or weight reduction. Eliminate
2) For the vibration generated by the rotor mass, it is necessary to perform the rotor static balance and low-speed dynamic balance test in advance. During the operation of the motor, if necessary, the high-speed dynamic balance test of the rotor can be performed by using the vibration-measuring balance, so that the rotor mass imbalance factor can be eliminated as much as possible.

3 vibration caused by motor bearings
For different power machines, the form of the motor bearing is different. Generally speaking, for small and medium-sized motors, rolling bearings are often used. For those large motors, sliding bearings are often used. Different types of motor bearings have different causes of vibration. During the working process of the motor, the force acting on the bearing causes two different vibrations: one is the relative vibration of the bearing housing and the rotor, and the other is the absolute vibration of the bearing housing itself.
There are four main factors that cause the vibration of rolling bearings:
1) Machining accuracy of the bearing: the ellipticity of the bearing ring, some gaps in the frame hole, and the waviness of the raceway surface. After a series of studies, the important vibration source of the bearing comes from the gap in the hole of the frame. If the gap is too large or too small, the motor will vibrate violently.
2) The matching precision when mounting the bearing refers to the matching precision between the bearing and the end cover and the bearing and the rotating shaft bearing. Therefore, in order to avoid the vibration of the motor, it is necessary to check the matching precision of the bearing, and the unreasonable matching precision should be timely. change.
3) Grease is often used between the machine and the machine to reduce the friction between each other. The motor bearing is usually coated with a certain amount of grease. Once the grease is too thick, its effect on the vibration damping of the rolling element It will be worse, if it is too thin, it will lead to dry friction. Therefore, in practice, it is necessary to apply a grease of reasonable consistency.
4) In the sliding bearing, the part of the support shaft is the lubricating oil film that is injected by the high-pressure oil pump. If the oil film is unstable, it will cause the whirl and foaming of the lubricating oil to some extent, which may cause the bearing to produce a series of abnormalities. Reaction. There are many factors that cause oil film instability, such as unstable load and incorrect center of the shaft.


4 vibration of the stator winding of the motor
When the motor is in operation, the stator windings are often affected by some forces, causing the system frequency or multiple frequency vibration of the windings. These forces generally include the following:
1) the interaction force between the current in the winding and the leakage flux;
2) rotor magnetic pull;
3) The force generated by thermal expansion and contraction.
When designing a motor, the technician often needs to consider the vibration of the groove and the top of the stator winding caused by the electromagnetic force. In order to avoid the vibration of the groove and the top, the grooved wire rod fastening structure or the end axial rigid support may be adopted. To reduce vibration.
5 to ensure the quality of the various parts of the motor
In order to fundamentally solve the vibration of the motor, the quality of each part of the motor should be guaranteed;
1) If the stator core is displaced, it should be repaired in time;
2) The bearing and bearing bush clearance should be controlled within a reasonable range, which should not be too large or too small;
3) Once the wear consistency of the bearing or the bearing bush is serious, the rolling bearing needs to be replaced, and for the sliding bearing, it must be recast and scraped;
4) If the spherical surface of the bearing in the motor is not well contacted, it should be ground to prevent line or point contact, so as to ensure good surface contact.
Third, the conclusion
The analysis shows that there are many factors that cause the vibration of the motor. The vibration problem of the motor exists at any time when the motor is installed and operated. Once the motor vibrates, it should respond in a timely manner. If you turn a blind eye to the vibration of the motor, it will cause long-term damage or immediate damage to the motor, which will directly lead to production loss. For how to better handle the vibration of the motor, we must distinguish the cause and result of the occurrence.