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The Ultimate Guide to Electrically Insulated Bearings
With the continuous development of modern industrial technology, motors and generators are increasingly used in industrial production. However, the problem of damage caused by current passing through bearings has become increasingly prominent. Bearing damage caused by this current flow is often called galvanic corrosion. Electrical corrosion not only shortens the service life of bearings, but also leads to equipment downtime and increased maintenance costs. In order to effectively prevent damage caused by current passing through the bearings, electrically insulated bearings came into being.
As a specially designed bearing, electrically insulated bearings can effectively prevent the passage of current, thereby protecting the normal operation of the bearing and equipment. This article will introduce in detail the definition, characteristics, advantages, detection methods, classification, installation, and application of electrically insulated bearings, and discuss the advantages of electrically insulated bearing manufacturers, in order to provide you with a comprehensive understanding and application guidance.
Since traditional bearings have no insulating layer, when current passes through, the current will generate arc discharge between the rolling elements and raceways, resulting in local high temperatures, which in turn may cause material melting and damage. An electrically insulated bearing is a bearing whose inner or outer rings are coated with a layer of insulating material, or whose rolling elements are made of ceramic materials to prevent the passage of electric current. This design enables electrically insulated bearings to effectively prevent damage to bearings caused by current in motors, generators and other equipment.
The selection of insulating materials and coating processes are key links in the manufacturing of electrically insulated bearings. Currently commonly used insulation materials include aluminum oxide, silicon nitride, etc. These materials not only have excellent insulation properties, but also have good wear resistance and corrosion resistance. The coating process usually uses plasma spraying technology, which can form a uniform and highly adhesive insulating layer on the bearing surface.
In addition, hybrid bearings are a special type of electrically insulated bearings whose rolling elements are made of ceramic materials, which have higher insulation properties and wear resistance. Ceramic materials, due to their inherently non-conductive nature, are effective at blocking the passage of electrical current, thus providing greater protection.
Advantages of electrically insulating bearings
Electrically insulating bearings have several unique characteristics that make them widely applicable and superior in industrial applications. The following are some of the main features of electrically insulating bearings:
Excellent insulation performance: Electrically insulated bearings can effectively prevent the passage of current and prevent the occurrence of electric corrosion by coating the inner or outer ring with a layer of insulating material, or using ceramic rolling elements. This insulation property makes it particularly suitable for use in equipment such as motors and generators, which can significantly improve the operational reliability of the equipment.
High durability: The insulation layer is usually made of high-performance materials such as aluminum oxide, which has good wear resistance and corrosion resistance and can maintain stable performance in harsh environments. The insulation layer has strong adhesion and is not easy to fall off, providing long-term protection even under high-load and high-speed working conditions.
High voltage resistance: Electrically insulated bearings can withstand voltages up to 1000V or higher, providing reliable electrical insulation protection. This high voltage withstand capability makes it valuable for applications in high voltage motors and generators.
Low maintenance costs: Because electrically insulated bearings can effectively prevent electrical corrosion, the frequency of bearing damage is reduced, thereby reducing equipment maintenance costs and downtime. Its long life and high reliability enable users to enjoy lower maintenance costs and higher equipment utilization.
Wide applicability: The key dimensions and technical parameters of electrically insulated bearings are the same as traditional bearings and can be directly replaced without additional design of surrounding components. This broad applicability enables a wide range of applications in a variety of motor and generator.Electrically insulated bearings are suitable for various motor and generator equipment, and have important application value especially in high-voltage and high-frequency current environments. Its wide applicability makes it an indispensable and important component in many fields such as the power industry, railway industry, machinery and metallurgical industry, mining machinery industry, etc. equipment.
Multiple types to choose from: There are many types of electrically insulating bearings to choose from, including deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, etc., which can meet the needs of different equipment and application scenarios. In addition, hybrid bearings, as a special type of electrically insulating bearings, provide higher insulation and mechanical properties.
To sum up, electrically insulated bearings have become an indispensable part of industrial equipment due to their advantages of improving equipment operation reliability, extending service life, reducing maintenance costs, economy, wide applicability, multiple types of options and environmental friendliness. component. Its unique advantages have made it widely used and recognized in various industries, making important contributions to improving the operating efficiency and economic benefits of equipment.
Inspection of electrically insulated bearings
The testing of electrically insulated bearings is an important step in ensuring their quality and performance. Through a series of scientific and effective testing methods, the insulation performance, mechanical properties and durability of electrically insulated bearings can be evaluated and verified. The following are some commonly used testing methods for electrically insulated bearings:
Insulation resistance measurement
Insulation resistance measurement is a basic method for evaluating the insulation performance of electrically insulating bearings. The insulation resistance of bearings is usually measured using an insulation resistance meter. Specific steps are as follows:
Connect the measuring electrodes of the insulation resistance meter to the inner and outer rings of the bearing respectively.
Measure the insulation resistance to ensure it reaches the specified standard value. Generally, the insulation resistance of electrically insulated bearings should be greater than 50MΩ to ensure good insulation performance.
Record the measurement results and evaluate whether the insulation performance of the bearing meets the requirements.
Shaft voltage and shaft current detection
By measuring shaft voltage and shaft current, the effect of current on the bearing can be judged and the effectiveness of electrically insulated bearings can be ensured. Specific steps are as follows:
While the motor is running, use a voltmeter to measure the voltage at both ends of the shaft to evaluate the voltage difference.
Use an ammeter to measure the current passing through the bearing and evaluate its current value.
Analyze the measurement results of shaft voltage and shaft current to ensure that they are within a safe range to avoid damage to the bearings.
High voltage withstand test
High voltage withstand test is an important method to evaluate the ability of electrically insulated bearings to withstand high voltages. High-voltage testing equipment is usually used to test bearings. The specific steps are as follows:
Connect the electrically insulated bearing to the high-voltage test equipment and gradually increase the applied voltage until the specified test voltage value is reached (such as 1000V or higher).
Maintain high pressure for a period of time and observe whether the bearing can withstand the high pressure without breakdown or damage.
Record the test results and evaluate the high voltage resistance performance of the bearing.
Mechanical performance testing
The mechanical properties of electrically insulated bearings are also important indicators for evaluating their quality. Commonly used mechanical property testing methods include:
Dimensional inspection: Use measuring tools to measure key dimensions such as the inner diameter, outer diameter, and width of the bearing to ensure that it meets the design requirements.
Rotation accuracy testing: Use precision testing equipment to measure the rotation accuracy of the bearing and evaluate its radial runout and axial runout.
Wear resistance testing: Wear resistance testing is performed by simulating actual working conditions to evaluate the wear resistance of bearings under high loads and high speeds.
Environmental adaptability testing
Electrically insulated bearings need to face various complex environmental conditions in practical applications, so environmental adaptability testing needs to be carried out to evaluate their performance stability in high temperature, low temperature, humid and other environments.
Through the above series of testing methods, the insulation performance, mechanical performance and environmental adaptability of electrically insulating bearings can be comprehensively evaluated to ensure that their quality and performance meet the requirements. In practical applications, the detection of electrically insulated bearings can not only ensure the normal operation of equipment, but also extend the service life of bearings, reduce equipment maintenance costs, and improve equipment operating efficiency.
Classification of electrically insulating bearings
There are many types of electrically insulating bearings, which can be divided into many types according to their structure and application scenarios. The following are the main classifications of electrically insulating bearings:
Electrically insulated deep groove ball bearings
Features: Electrically insulated deep groove ball bearings can effectively prevent the passage of current by coating the inner or outer ring with insulating material, or using ceramic rolling elements. Its structure is simple and suitable for bearing radial load and certain axial load.
Application: Widely used in motors, generators and other equipment, especially those requiring high insulation performance and high durability.
Specifications: inner diameter range 40mm-140mm, outer diameter range 80mm-300mm, width range 18mm-62mm.
Electrically insulated angular contact ball bearings
Features: Electrically insulated angular contact ball bearings can withstand combined radial and axial loads and have strong axial load capacity. Reliable insulation protection is provided by coating with insulating materials or using ceramic rolling elements.
Application: Suitable for motors, generators and other equipment that require high speed and high precision.
Specifications: inner diameter range 40mm-140mm, outer diameter range 80mm-300mm, width range 18mm-62mm.
Electrically insulated cylindrical roller bearings
Features: Electrically insulated cylindrical roller bearings can withstand large radial loads and have high rigidity and durability. By coating the inner or outer ring with insulating material, it provides reliable insulation performance.
Application: Widely used in heavy-duty equipment, such as high-power motors, generators, etc.
Specifications: inner diameter range 45mm-140mm, outer diameter range 100mm-300mm, width range 25mm-62mm.
Hybrid ceramic bearings
Features: The rolling elements of hybrid ceramic bearings are made of ceramic materials, which have higher insulation performance and wear resistance. The non-conductive nature of ceramic rolling elements blocks the passage of electrical current effectively.
Application: Especially suitable for motors, generators and other equipment that require high insulation performance and high durability.
Advantages: Provide higher electrical insulation protection and mechanical performance, extending the service life of bearings.
Electrically insulated self-aligning ball bearings
Features: Electrically insulated self-aligning ball bearings have an self-aligning function and can compensate for shaft bending and installation errors. Electrical insulation protection is provided by coating with insulating material or using ceramic rolling elements.
Application: Suitable for motors, generators and other equipment that require alignment function and electrical insulation performance.
Specification: customized according to customer needs.
Electrically insulated spherical roller bearings
Features: Electrically insulated spherical roller bearings have an aligning function and can withstand large radial loads and axial loads. Provide reliable electrical insulation properties by coating with insulating materials.
Application: Widely used in equipment requiring high load capacity and alignment function, such as high-power motors, generators, etc.
Specification: customized according to customer needs.
There are various types of electrically insulating bearings to meet the needs of different equipment and application scenarios. In practical applications, choosing the appropriate type of electrically insulated bearings can not only improve the operational reliability and service life of the equipment, but also effectively prevent electrical corrosion, reduce maintenance costs, and ensure efficient operation of the equipment.
Installation of electrically insulating bearings
The installation of electrically insulated bearings is a key link in ensuring their performance and service life. Correct installation methods can effectively prevent bearing damage and early failure and improve the operational reliability of the equipment. The following are the main installation methods and precautions for electrically insulated bearings:
Cold installation/mechanical method
Features: The cold mounting method is suitable for bearings with loose fits. The bearings are pressed onto the shaft or into the bearing seat through a press. This method is simple and easy, but you need to pay attention to the uniformity and correctness of the installation force.
Steps
Clean bearings and related parts to ensure they are dust-free and dirt-free.
Check the size and processing accuracy of relevant parts to ensure they meet design requirements.
Use a press to press the inner ring or outer ring of the bearing into the shaft or bearing seat. Be careful not to transmit the installation force through the rolling elements.
Use special assembly tools, such as assembly sleeves, to ensure even distribution of installation force.
Note: During installation, avoid using a hammer to directly hit the bearing to prevent damage to the rolling elements and raceways.
Hot installation
Features: Thermal installation is suitable for bearings with large interference. The bearing or bearing seat is heated and expanded before installation. This method can prevent the bearing from bearing unnecessary external forces and ensure installation accuracy.
Steps
Put the bearing or bearing seat into the heating equipment and heat it evenly to 80℃-100℃.
Quickly install the heated bearing or bearing seat into the shaft or bearing seat to ensure that it is installed in place.
After installation is completed, wait for the bearing to cool down and ensure that the inner and outer rings fit tightly with the shaft and bearing seat.
Note: The heating temperature should not exceed 120°C to prevent bearing hardness reduction and coating damage. During the heating process, avoid contact between the bearing and the bottom of the oil tank. You can use a metal grid or hanging device.
Hydraulic installation
Features: The hydraulic method is suitable for occasions where precise control of installation pressure is required, and bearings are installed through hydraulic tools. This method can provide uniform installation force and ensure the installation quality of the bearing.
Steps
1. Prepare hydraulic tools and special assembly tools, such as assembly casings.
2. Use a hydraulic tool to apply even pressure to install the bearing inner or outer ring into the shaft or bearing seat.
3. During the installation process, keep the pressure uniform and stable to avoid excessive impact.
4. After installation is completed, check the bearing fit to ensure correct installation.
Precautions: During the hydraulic installation process, attention should be paid to operational safety and to avoid misoperation and overloading of hydraulic tools.
Installation Precautions
Cleaning work: Before installing the bearing, ensure that the bearing and related parts are clean to prevent dust and impurities from entering the inside of the bearing.
Check the fit: Before installation, the fit of the shaft and bearing seat should be carefully checked to ensure that the dimensions and tolerances meet the requirements.
Correct mounting force: During the installation process, the correct mounting force and tools should be used to avoid transmitting the mounting force through the rolling elements and prevent bearing damage.
Lubrication: During the installation process, lubricants can be used appropriately to reduce friction and installation resistance and ensure smooth installation of the bearings.
Proper installation of electrically insulated bearings is critical to their performance and service life. By adopting appropriate installation methods and precautions, bearing damage and early failure can be effectively prevented, and the operational reliability and economic benefits of the equipment can be improved.
Applications of electrically insulating bearings
Electrically insulated bearings are widely used in multiple industries and application scenarios due to their superior electrical insulation properties and high durability. The following are the main application areas and specific cases of electrically insulating bearings:
Power Industry
Wind Turbine: Electrically insulating bearings play a vital role in wind turbines. The operating environment of wind turbines is complex and often faces harsh conditions such as high humidity, high load and high speed. Electrically insulated bearings can effectively prevent the passage of current, protect the bearings from electrical corrosion, and improve the operational reliability and service life of wind turbines.
Hydraulic generator: In hydroelectric generators, electrically insulated bearings can also prevent electrical corrosion and ensure stable operation of the generator. Its high durability and low maintenance requirements allow hydroelectric equipment to reduce operating costs.
Railway industry
Traction motor: The traction motor of railway vehicles needs to work in a high-load and high-frequency operating environment. Electrically insulated bearings can effectively prevent the passage of current, prevent electrical corrosion, and extend the service life of the motor. Especially in high-speed trains and heavy-duty freight trains, the application of electrically insulated bearings has greatly improved the reliability and safety of the equipment.
Machinery and metallurgical industry
High-power variable frequency motors: In the machinery and metallurgical industries, high-power variable frequency motors are widely used in cranes, textile machines, printing presses, ironmaking equipment, steel rolling equipment and other equipment. Electrically insulated bearings can prevent current from passing through the bearings, reduce electrical corrosion and wear, and improve the operating efficiency and service life of the equipment.
Metallurgical equipment: The application of electrically insulated bearings in metallurgical equipment can effectively prevent bearing damage caused by current, ensure efficient operation of equipment, and reduce the frequency of maintenance and replacement.
Mining machinery industry
High-power equipment: In mining machinery, such as mining machines, coal preparation machines, crushers and other equipment, electrically insulated bearings can prevent electrical corrosion and improve the reliability and service life of the equipment. These devices often operate in harsh environments, and the durability and low maintenance requirements of electrically insulated bearings can significantly reduce operating costs.
Industrial motors and generators
Electric Motors: Electrically insulated bearings are widely used in various types of electric motors, including AC motors and DC motors. Its insulation properties can prevent electric current from passing through the bearings, reduce electrical corrosion, and improve the operating reliability and efficiency of the motor.
Generator: In generators, electrically insulated bearings can prevent the passage of current, protect the bearings and lubricants from electrical corrosion, and improve the stability and service life of the generator. Especially in the fields of wind power and hydropower, the application of electrically insulated bearings has significantly improved the operating efficiency and economic benefits of equipment.
Other application areas
Petrochemical industry: In petrochemical equipment, the application of electrically insulated bearings can prevent bearing damage caused by current and improve the operational reliability and safety of the equipment.
Aerospace: In aerospace equipment, the application of electrically insulated bearings can prevent current from passing through the bearings, protect the stable operation of the equipment, and ensure flight safety.
Electrically insulated bearings are widely used in multiple industries and application scenarios due to their superior insulation properties and high durability. Its significant advantages in improving equipment operation reliability, extending service life and reducing maintenance costs make it an indispensable and important component in modern industrial equipment.
Manufacturer of electrically insulating bearings
The manufacturing of electrically insulated bearings requires a high level of technology and craftsmanship, and high-quality manufacturers can provide high-performance and high-reliability electrically insulated bearings. Here are some famous electrically insulating bearing manufacturers and their advantages:
SKF
There is no doubt that SKF is the most well-known bearing brand in the world. The latest stage that SKF has developed in this area is the ability to handle dielectric breakdown voltages of 1,000V. The insulating coating on the outer ring of INSOCOAT bearings is made of aluminum oxide and uses plasma spray technology.The VL024 and VA309 have a breakdown voltage of 500V, and the VL0241 and VA3091 have a breakdown voltage of up to 1,000V. VA309 and VA3091 are suitable for traction motor bearings.
Technological leadership: SKF uses the most advanced spraying technology and materials to ensure the high quality and reliability of electrically insulated bearings. Its products provide excellent electrical insulation performance and durability in high voltage and high load environments.
Various products: SKF provides a variety of types and specifications of electrically insulated bearings, including deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, etc., to meet the needs of different customers.
Quality service: SKF focuses on customer service and provides comprehensive technical support, consulting and after-sales services to ensure customer satisfaction.
Global supply: SKF’s products are sold all over the world, with extensive market coverage and a good reputation.
NKE Austria GmbH
Advanced technology: NKE uses plasma spraying technology to coat the inner or outer ring of the bearing with an oxide ceramic insulation layer to ensure the high insulation performance and durability of the bearing.
Multiple models: NKE provides multiple models of electrically insulated bearings, including SQ77 with outer ring insulation and SQ77E with inner ring insulation, which can meet the needs of different application scenarios.
Global certifications: NKE’s production plants are ISO 9001:2008, ISO 14001:2004 and OHSAS 18001 certified, ensuring high standards of product quality and environmental management.
Aubearing
Advanced technology: Aubearing uses advanced spraying processes and materials to ensure the high quality and durability of electrically insulated bearings.
Hybrid bearings: Aubearing’s hybrid bearings use ceramic balls as rolling elements, providing excellent electrical insulation and mechanical properties. The non-conductive nature of ceramic balls can effectively prevent the passage of current and increase the service life of the bearing.
High performance: Aubearing’s electrically insulated bearings perform well in high-frequency operating environments and are particularly suitable for demanding applications such as electric motors and generators.
Global trust: Aubearing’s electrically insulated bearings have won the trust of customers around the world with their high performance and high reliability.
Rich experience: As a Chinese bearing manufacturer, Aubearing has than 10 years of experience in the design and research of electrically insulated bearings, and can provide high-performance, cost-effective electrically insulated bearings.
Multiple types: Aubearing provides various types of electrically insulated bearings, including deep groove ball bearings, cylindrical roller bearings, aligning ball bearings, angular contact ball bearings, tapered roller bearings, etc., to meet the needs of different customers.
Jiuxing Bearing Technology Co., Ltd.
High performance: The electrically insulating bearings produced by Jiuxing Bearing Technology Co., Ltd. are coated with aluminum oxide and can withstand voltages up to 1000V DC, providing excellent electrical insulation performance.
Advanced equipment: Jiuxing Bearing Technology Co., Ltd. has advanced bearing production equipment and technology, capable of providing high-quality electrically insulated bearings.
Wide application: Jiuxing Bearing Technology Co., Ltd.’s electrically insulating bearings are widely used in many industries such as electric power, railways, machinery, metallurgy, and mining, and have a good market reputation.
By choosing a suitable electrically insulating bearing manufacturer, customers can obtain high-quality, high-performance electrically insulating bearing products to ensure stable operation and long life of the equipment. These manufacturers have won the trust and recognition of customers around the world with their advanced technology, high-quality products and excellent services.
Conclusion
As an important mechanical basic component, electrically insulated bearings play a vital role in modern industrial equipment. By effectively preventing the passage of electric current, electrically insulating bearings can prevent electrical corrosion, improve the operational reliability and service life of equipment, reduce maintenance costs, and ensure efficient operation of equipment. A detailed introduction to the definition, characteristics, advantages, detection methods, classification, installation and application of electrically insulated bearings provides you with a comprehensive understanding and application guidance. In practical applications, selecting the appropriate type of electrically insulated bearings and using correct installation methods and testing methods can ensure the performance and service life of the bearings.
In addition, by choosing a high-quality electrically insulated bearing manufacturer, customers can obtain high-quality, high-performance electrically insulated bearing products to ensure stable operation and long life of the equipment. Manufacturers such as ubearing, NKE Austria GmbH, CeramicSpeed, CoatMaster and Jiuxing Bearing Technology Co., Ltd. have won the trust and recognition of global customers with their advanced technology, high-quality products and excellent services.
In short, electrically insulated bearings are an indispensable part of modern industrial equipment. Their superior insulation properties and high durability have made important contributions to improving the operating efficiency and economic benefits of equipment. It is hoped that this article can provide readers with valuable information to help them select and use appropriate electrically insulated bearings in practical applications and improve the operational reliability and economic benefits of equipment.
FAQ
What are electrically insulated bearings?
Electrically insulated bearings are bearings that prevent the passage of current by coating insulating materials or using ceramic rolling elements. They are mainly used to prevent electrical corrosion and improve the operational reliability of equipment.
What are the main application areas of electrically insulating bearings?
Electrically insulated bearings are widely used in the power industry, railway industry, machinery and metallurgical industry, mining machinery industry and other fields, especially in motor and generator equipment.
How to detect the insulation performance of electrically insulating bearings?
Evaluate the insulation performance and mechanical performance of electrically insulated bearings by measuring insulation resistance, shaft voltage and shaft current, conducting high-voltage withstand testing and mechanical performance testing.
What are the installation methods for electrically insulated bearings?
The installation methods of electrically insulated bearings include cold installation/mechanical method, hot installation and hydraulic method. The correct installation method can ensure the performance and service life of the bearing.
How to choose the right electrically insulating bearing manufacturer?
Choose manufacturers with advanced technology, quality products and quality services, such as SKF, Aubearing, NKE Austria GmbH, CeramicSpeed, CoatMaster and Jiuxing Bearing Technology Co., Ltd., to ensure high-quality electrically insulating bearing products.