Although the structure of an electric motor may seem relatively simple, it is also very prone to causing serious losses in terms of mechanical failures. Among the mechanical failures of the entire motor structure, the most common one is the bearing failure of the motor, most of which is caused by motor bearing heating. Once the motor bearing experiences a heating fault, it can cause the motor lubricating grease to dissolve and overflow, while in severe cases, it can cause the lubricating grease to burn, directly leading to the burning of the motor bearing.

The maintenance of motor bearings is one of the important aspects of overall motor maintenance, and it is also the most important type of motor maintenance. Regardless of the type of bearing used in the motor, if the bearing is damaged, it is highly likely to cause the stator and rotor of the motor to sweep the bore, and through the uninterrupted operation of the motor, cause the insulation of the motor coil to burn out. At the same time, due to the heating of the bearings, the leakage of lubricating oil may occur. Although the motor can operate normally, the leaked grease is highly likely to accumulate on the motor coil, causing dust and other debris to accumulate on the coil and burn the motor insulation.

1. The main reason for this fault caused by the mutual friction between the motor bearing and the bearing cover is that the motor did not have tight machining during the processing of the bearing cover or friction scratches appeared during assembly, resulting in local friction phenomena during the rotation of the motor bearing. If there is slight friction, the bearing will generate heat, but there will be no smoke. Opening the motor cover for inspection will reveal black friction marks at the friction point. If it is due to eccentricity of the inner circle of the motor bearing cover or scratches during assembly, it can cause severe friction of the motor bearing and emit smoke.

2. The problem of oil filling method for motor bearings generally involves oiling the outer side of the bearing to prevent excessive oiling and facilitate it. If the motor does not operate for a sufficient length of time, it is difficult for lubricating oil to be distributed inside the bearing. For high-speed or large motors, this often causes the bearings of the motor to heat up.

3. Damage to motor bearings

The steel balls of the motor bearings are not round or broken, and after maintenance, they are not strictly inspected, as well as the corrosion and fracture of the outer ring of the motor bearings caused by the absence of waterproof rings during assembly, all of which can cause friction loss and heat generation in the motor bearings.

4. If the motor belt is too tight or the coupling installation is not standardized, as well as the uneven installation of the motor coupling, the bearing temperature of the motor bearing will rise sharply due to an increase in load. During the operation of the motor, if it is found that the motor does not generate heat during idle operation, but generates a lot of heat under load, it is necessary to check whether the motor belt is too tight and whether the coupling is uneven.

5. The most common type of improper assembly of motor bearings is improper assembly of motor bearings, such as bearing wear caused by uneven tapping of the inner ring during the bearing cold assembly process, which leads to the loss of the original interference or reduction of the interference between the inner ring and the bearing, resulting in the phenomenon of running the inner ring; During the assembly process of the motor's cover end, the lack of uniform tapping caused the loose fit between the cover end bearing chamber and the outer ring of the bearing, resulting in the phenomenon of the bearing running out of the outer ring.

6. The presence of foreign objects or impure grease in the motor bearing compartment, such as small rigid substances in the bearing cage, can cause damage to the bearing raceway during motor operation and increase temperature, leading to the burning of the motor bearings.

7. There are some quality issues with the motor bearings themselves, such as rust on the raceway, excessive clearance, deformation of the cage, and inflexibility in rotation.