Compared with low-voltage motors, high-voltage motors, especially high-voltage asynchronous motors, are mostly based on cage-type rotor structures. During the manufacturing and operation of the motors, due to improper matching of mechanical structural parts, the motors may cause severe vibrations, which may be radial vibrations or axial vibrations.
The uneven air gap between the stator and the rotor is a key factor in motor vibration. During the production process, when the motor base, stator core and rotor are not aligned, the uneven air gap will be directly caused. After the motor is powered on, the unilateral magnetic pull will cause electromagnetic vibration of the motor. In addition to mechanical vibration, the vibration caused by this reason is also accompanied by low-frequency electromagnetic sound.
For motors in operation, especially those that have been repaired, due to long-term operation, the motor bearings, bearing chambers, and bearing seat diameters may have some dimensional deviations, resulting in unreasonable matching relationships and motor vibration problems. For the matching parts of the inner and outer rings of the bearings, when there is a serious loosening problem, the bearings will heat up and burn out in a short period of time due to the running of the bearings, which is a fatal quality failure.
As for the rotor part of the motor, due to the deformation of the rotor bars and the failure of the original balance state during the operation of the motor, the rotor body loses balance. This is a common cause of failure during the operation of high and low voltage motors.
For high-voltage motors, especially those using sliding bearings, the misalignment of the magnetic centerline is the fundamental cause of the motor’s axial vibration. This is the key that must be controlled during the installation and use of high-voltage motors.
In order to prevent similar problems from occurring, starting process control is particularly important for cage-type high-voltage motors to prevent motor starting difficulties caused by insufficient power capacity.
In the analysis and inspection of motor vibration problems, necessary items should be checked to find out the root cause of the vibration. Some motor repair units prefer to replace bearings. Objectively speaking, bearing non-conformity will cause motor vibration problems, but bearing conformity may not necessarily solve the motor vibration problem. Therefore, a deep and comprehensive analysis is more conducive to solving the problem.
As for electromagnetic reasons, winding asymmetry and electrical quality failure of winding will lead to uneven magnetic field of the motor, and also cause electromagnetic vibration of the motor. This vibration is more likely to manifest as violent shaking accompanied by severe dull sound, which is different from mechanical vibration and can be clearly distinguished during the analysis process.
Post time: Feb-14-2025