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Why we use electrically insulated bearing?

Views: 812     Author: Site Editor     Publish Time: 2021-04-12      Origin: Site

Insulated angular contact ball bearings

Electrically Insulated bearings are mainly used in motor products. Its use is determined according to the power state of the motor. Normal grid power supply has no high-frequency voltage and current components. Generally, insulated bearings are not used. Only high-voltage motors and large motors such as 400 and above are used.

But now the variable frequency power supply power supply, because the quality of the power supply contains a lot of high-frequency components, which causes the motor shaft current to increase, so this issue should be considered for specifications above 400KW, and even the smaller specifications should also consider installing insulation Bearings according to the usage conditions. such as the main motors used in electric vehicles and electric rail locomotives, are generally about 100KW, and electrical insulated bearings must be used (or other insulation structures are used to ensure that the shaft current does not flow).


With the development of society and the progress of industrial technology, more and more equipment and application scenarios have stricter  requirements on the service life, noise level, and stability of bearings. As the most widely used power output device in industry, the motor is the most widely used power output device. Stability and service life play a particularly critical role in the application of equipment.

Motors are the source of power in the industrial field. They are used in machinery and equipment, automotive, aerospace, trains and other industries. There are many types of motors:

1. Servo motor

2. Stepping motor

3. Torque motor

4. Switched reluctance motor

5. Brushless DC motor

6. DC motor

7. Asynchronous motor

8. Synchronous motor


Motor bearings play an important role in the efficient operation of the motor. Even if the production is strictly controlled during the manufacturing process of the motor, it is difficult to completely avoid the magnetic asymmetry of the armature and the rotor. This asymmetry will generate voltage between the stators. The current that passes through the bearing is more serious, especially in AC motors. This current produces corrosion pits, melt marks, electric erosion marks, discoloration, wear and other damage on the surface of bearing raceways and rolling elements. Of course, motors using inverter and frequency conversion technology can also produce this phenomenon. In order to block the current flowing through the bearing, it is necessary to cut off the circuit, so that the insulated bearing and the insulated bearing housing came into being. The insulated bearing housing is made of insulating material with a certain hardness in the bore and end face of the bearing chamber.


Insulated bearing for motor

Electrically insulated bearing have very high cost than the normall deep groove ball bearing, cylindrical roller bearings, spherical roller bearings, thrust roller bearings, linear motion bearings, tapered roller bearings and so on. The function of insulation can make the bearing free from current corrosion, so as to improve the service life of the bearing, protect the safety of the equipment, reduce the downtime of the equipment, and create more value, which is far more than the cost of purchasing the insulated bearing, so the insulated bearing will be more and more used in the market


Electrically insulated bearings use a special spraying process to spray high-quality coating on the outer surface of the bearing. The coating has a strong bond with the substrate and has good insulation performance. It can avoid the electric corrosion effect of the induced current on the bearing and prevent the current from affecting the grease and rolling elements. , The damage caused by the raceway can improve the service life of the bearing. The process has been continuously improved. for insulated bearings, a layer of 100μm thick coating is provided on the surface of the outer ring or inner ring, which can withstand a voltage of up to 1000 V DC. The special spraying process can form a layer of uniform thickness, strong and uniform coating, and then further processed to make it not affected by moisture and humidity.

structure of insulated bearing in motor

Where the electrically insulated bearing used in?

Electric power industry:

insulated cylindrical roller bearing for generator, wind power generator, hydro generator, thermal generator,

applicable to motor, generator, especially used in frequency conversion motor.


Railway Industry:

Insulated cylindrical roller bearing for diesel locomotive traction motor:

applied to locomotive, etc


Mechanical and metallurgical industry:

insulated bearings for high-power frequency conversion motors:

applied to cranes, textile machines, printing machines, iron making equipment, steel-making equipment, rolling equipment, cutting equipment, coking equipment, smelting complete equipment, etc


Mining machinery industry:

insulated bearing for high-power high-voltage motor,

applied to mining machine, coal preparation machine, coal washing machine, crusher, ball mill, grinder, sand mill


Petrochemical Industry:

insulated bearings for high-power explosion-proof motors:

applied to compressors, etc


High voltage motors can be used to drive various machines. Such as compressor, water pump, crusher, cutting machine, transport machinery and other equipment, for mining, machinery industry, petrochemical industry, generator and other industries as prime mover. The motors used to drive the blowers, coal mills, rolling mills and hoists shall indicate the purpose and technical requirements when ordering, and special design shall be adopted to ensure reliable operation, electrically insulated bearing can save your time and support your machine More efficient.

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