The cause of the axial vibration failure of the motor and how to deal with it
The electric motor is one of the commonly used equipments in the production of the enterprise, and the reliability and stability of its operation have a great influence on the normal operation of the production device. If the fault caused by the abnormal axial matching of the motor is not solved in time, it will affect the production. Therefore, how to judge and deal with this problem is very important.
1. Reasons for motor axial vibration failure
According to the production practice experience, the causes of axial vibration of the motor usually have the following aspects:
(1) The bearing or bearing bush of the motor is seriously worn, and the gap is too large, resulting in a "shaft lift" phenomenon.
(2) The motor air gap is not uniform or the motor winding is faulty.
(3) The rotor of the motor is unbalanced, or the balance block moves after the rotor is balanced, and the fan blades are damaged.
(4) The motor shaft is bent or the journal is severely worn.
(5) The axial positioning offset of the motor rotor.
(6) The installation base of the motor is not level, or the rigidity is not enough, or the anchor bolts are not fixed.
The motor is disassembled and examined one by one. The axial vibration of the motor is caused by improper selection of the motor bearing (the original bearing is a normal bearing). However, after replacing the non-load end bearing (positioning end) with the C3 series, it was found that the axial vibration was still too large when the vehicle was re-commissioned. Once again, the motor was disassembled, re-examined, the rotor volume was re-measured, the depth of the end cap of the inner and outer oil caps of the positioning end, and the bearing size were found: The inner and outer oil cap end caps are not deep enough, and there is a gap of 2.7 mm between the end face of the bearing and the outer ring of the bearing.
Analysis: It is for this reason that the axial positioning of the rotor is caused. During operation, the motor generates axial vibration under the action of electromagnetic force.
2. Treatment of motor axial vibration fault
(1) Processing method
a. According to the measured gap value between the end face of the oil cap and the outer ring of the bearing, the 2.7mm thick bakelite adjustment pad is made.
b. Place the rotor of the motor in the center of the magnetic field of the motor, and install the bakelite adjustment pad between the non-load end oil cap and the outer ring of the bearing, and then reload the motor.
(2) Axis adjustment effect
After the bearing pad is installed with the adjusting pad, the motor is tested and the boring phenomenon is eliminated. The horizontal vibration speed of the motor was measured to be 1.9 mm/s, the vertical vibration speed was 2.2 mm/s, and the axial vibration speed was 2.0 mm/s. That is, the rotor vibration meets the standard requirements and the test is qualified.
3. Summary analysis
Axial positioning of the motor is very important. Due to the positioning problem, the motor rotor is deviated from the center of the magnetic field or the axial amount is too large, which will cause the motor shaft and bearing to heat or even damage. Therefore, the maintenance of the motor should be carefully analyzed before the inspection to determine the cause of the failure. Secondly, when it is found that the bearing end is worn or renewed, the axial fit size should be thoroughly checked and adjusted. (Motors with ball bearings on both sides should also consider the cooperation with non-locating bearings) to ensure good positioning of the rotor of the motor, thus avoiding the occurrence of axial vibration of the rotor.
1. Reasons for motor axial vibration failure
According to the production practice experience, the causes of axial vibration of the motor usually have the following aspects:
(1) The bearing or bearing bush of the motor is seriously worn, and the gap is too large, resulting in a "shaft lift" phenomenon.
(2) The motor air gap is not uniform or the motor winding is faulty.
(3) The rotor of the motor is unbalanced, or the balance block moves after the rotor is balanced, and the fan blades are damaged.
(4) The motor shaft is bent or the journal is severely worn.
(5) The axial positioning offset of the motor rotor.
(6) The installation base of the motor is not level, or the rigidity is not enough, or the anchor bolts are not fixed.
The motor is disassembled and examined one by one. The axial vibration of the motor is caused by improper selection of the motor bearing (the original bearing is a normal bearing). However, after replacing the non-load end bearing (positioning end) with the C3 series, it was found that the axial vibration was still too large when the vehicle was re-commissioned. Once again, the motor was disassembled, re-examined, the rotor volume was re-measured, the depth of the end cap of the inner and outer oil caps of the positioning end, and the bearing size were found: The inner and outer oil cap end caps are not deep enough, and there is a gap of 2.7 mm between the end face of the bearing and the outer ring of the bearing.
Analysis: It is for this reason that the axial positioning of the rotor is caused. During operation, the motor generates axial vibration under the action of electromagnetic force.
2. Treatment of motor axial vibration fault
(1) Processing method
a. According to the measured gap value between the end face of the oil cap and the outer ring of the bearing, the 2.7mm thick bakelite adjustment pad is made.
b. Place the rotor of the motor in the center of the magnetic field of the motor, and install the bakelite adjustment pad between the non-load end oil cap and the outer ring of the bearing, and then reload the motor.
(2) Axis adjustment effect
After the bearing pad is installed with the adjusting pad, the motor is tested and the boring phenomenon is eliminated. The horizontal vibration speed of the motor was measured to be 1.9 mm/s, the vertical vibration speed was 2.2 mm/s, and the axial vibration speed was 2.0 mm/s. That is, the rotor vibration meets the standard requirements and the test is qualified.
3. Summary analysis
Axial positioning of the motor is very important. Due to the positioning problem, the motor rotor is deviated from the center of the magnetic field or the axial amount is too large, which will cause the motor shaft and bearing to heat or even damage. Therefore, the maintenance of the motor should be carefully analyzed before the inspection to determine the cause of the failure. Secondly, when it is found that the bearing end is worn or renewed, the axial fit size should be thoroughly checked and adjusted. (Motors with ball bearings on both sides should also consider the cooperation with non-locating bearings) to ensure good positioning of the rotor of the motor, thus avoiding the occurrence of axial vibration of the rotor.
