In the rotor systems of high-speed centrifugal compressors, magnetic bearings support rotors at speeds of tens of thousands of rpm with non-contact magnetic suspension——no contact, no friction, no wear and no lubricating oil. In the vacuum chambers of flywheel energy storage systems, magnetic bearings suspend rotors in vacuum, minimizing energy losses for long-term high-efficiency energy storage and release. In the ultra-high vacuum environments of turbomolecular pumps, magnetic bearings support rotors at high speeds without oil contamination, ensuring cleanliness for semiconductor and vacuum coating processes. In high-speed motorized spindles, magnetic bearings achieve micron-level machining accuracy and nanometer-level surface quality with extremely high rigidity and damping characteristics. In every cutting-edge rotating device requiring ultra-high speed, non-contact operation, wear-free operation and maintenance-free performance, magnetic bearings are the revolutionary precision components achieving breakthrough performance limits.

 

Magnetic bearings (also known as magnetic suspension bearings) are a type of bearing that uses magnetic field forces to suspend rotors in space, achieving non-contact support. Unlike traditional rolling bearings and plain bearings, magnetic bearings have no mechanical contact between rotors and stators, relying on electromagnetic forces to balance rotor weight and external loads, maintaining stable suspension in the air gap. By eliminating mechanical contact, magnetic bearings fundamentally eliminate friction, wear and lubricant use, achieving truly wear-free, maintenance-free and oil-free operation. Magnetic bearings can operate long-term at extremely high speeds (up to 100,000 rpm and above), with unparalleled advantages in extreme environments such as vacuum, cleanroom, high temperature and low temperature.

 

Magnetic bearings are classified into active magnetic bearings (AMB), passive magnetic bearings (PMB) and permanent magnetic suspension bearings based on operating principles. Active magnetic bearings use controllable electromagnetic forces generated by electromagnets to suspend rotors, with closed-loop control systems consisting of displacement sensors, controllers and power amplifiers providing real-time electromagnetic force adjustment for stable suspension and precise position control. Active magnetic bearings offer adjustable stiffness and damping, strong adaptability and high control precision, making them the most widely used type in industrial applications. Passive magnetic bearings use repulsive or attractive forces between permanent magnets for suspension, with simple structures and no external power requirement, but with low damping and poor stability, typically used in combination with active magnetic bearings or auxiliary bearings. Magnetic bearings are widely used in high-speed motors, centrifugal compressors, turbomolecular pumps, flywheel energy storage systems, high-speed spindles, spacecraft attitude control flywheels, artificial heart blood pumps and various cutting-edge equipment with ultra-high speed, contamination-free and maintenance-free requirements.

 

NMT Magnetic Bearing Technology Solutions

 

Japan NMT magnetic bearings are revolutionary product series developed specifically for the stringent requirements of ultra-high-speed non-contact rotating equipment——non-contact, wear-free, maintenance-free and high reliability.

 

Active Magnetic Suspension Control System——The core of active magnetic bearings lies in their closed-loop control systems. NMT magnetic bearing systems consist of displacement sensors, controllers, power amplifiers and electromagnet actuators. Displacement sensors (eddy current sensors or inductive sensors) monitor rotor position deviations in X, Y and Z axes at extremely high sampling rates, feeding displacement signals back to digital controllers. Controllers calculate required electromagnetic force adjustments based on preset suspension positions and PID control algorithms, outputting control signals to power amplifiers. Power amplifiers convert control signals to drive currents, driving electromagnets to generate precise electromagnetic forces that return rotors to target suspension positions. This closed-loop control cycle operates at tens of thousands of times per second, ensuring stable rotor suspension during high-speed rotation and external disturbances. NMT digital controllers utilize high-performance DSP and FPGA architectures with optimized control algorithms, fast response, strong anti-interference capability and support for multiple communication interfaces and remote monitoring functions.

 

High Stiffness and High Damping Characteristics——Compared to traditional bearings, active magnetic bearing stiffness and damping are “programmable”——PID parameter adjustment allows online tuning of bearing stiffness and damping characteristics for different speeds, loads and operating conditions. NMT magnetic bearing control systems support multi-degree-of-freedom independent control and cross-coupling control, providing independent stiffness and damping adjustment in radial and axial directions. High stiffness characteristics maintain precise rotor axis position under external disturbances such as cutting forces and aerodynamic loads, with positioning accuracy reaching micron levels. High damping characteristics effectively suppress rotor vibration and instability near critical speeds, ensuring stable operation across the full speed range. Validated through rigorous rotor dynamics matching and control system optimization, NMT magnetic bearings maintain sub-micron rotational accuracy at ultra-high speeds of 50,000-100,000 rpm.

 

Non-Contact, Wear-Free, Maintenance-Free——The fundamental advantage of magnetic bearings lies in their non-contact operating mode. Rotors and stators are separated by air gaps (typically 0.2-1.0mm) with no mechanical contact, fundamentally eliminating friction, wear and mechanical fatigue. Magnetic bearings require no lubricating oil or grease, eliminating lubricant loss, aging and contamination issues, particularly suitable for cleanrooms, vacuum environments and applications where lubricant contamination is prohibited. No periodic lubricant replacement, no wear condition monitoring and no maintenance downtime for bearing wear——magnetic bearing theoretical service life under normal conditions is limited only by electronic component life, far exceeding any mechanical contact bearing. For applications requiring long-term continuous operation with difficult maintenance access (such as space equipment, deep-sea equipment and remote unmanned stations), magnetic bearing maintenance-free characteristics have decisive strategic significance.

 

Ultra-High-Speed Adaptability and Heat Generation Control——Magnetic bearing speed limits are not constrained by rolling element centrifugal forces or cage strength, limited only by rotor material strength and electromagnetic system response speed. NMT magnetic bearings support ultra-high-speed operation above 100,000 rpm——several times the speed limits of rolling bearings. During ultra-high-speed operation, magnetic bearing heat generation primarily comes from electromagnet iron losses and copper losses (electromagnetic losses), rather than mechanical friction heat. NMT magnetic bearing electromagnets use laminated cores (silicon steel sheets) to reduce eddy current losses, with coils using high-conductivity copper to reduce copper losses. Cooling systems (water-cooling or air-cooling) effectively remove electromagnet heat, maintaining temperature rise within reasonable limits. Validated through rigorous ultra-high-speed thermal balance testing, NMT magnetic bearings maintain stable suspension performance and acceptable temperature rise levels during sustained 100,000 rpm operation.

 

Auxiliary Bearings and Emergency Protection System——Although magnetic bearings operate without contact under normal conditions, rotors may drop and contact auxiliary bearings during system power loss, control failure or overload conditions. NMT magnetic bearings feature high-performance auxiliary bearings (mechanical ball bearings or plain bearings) that temporarily support rotors under abnormal conditions, preventing direct contact damage between electromagnets and rotors. Auxiliary bearings have sufficient strength and impact resistance to absorb impact energy during rotor drops, supporting rotor re-suspension after fault clearance. Auxiliary bearings use high-temperature, long-life materials with wear detection devices that provide early warning when approaching life limits. NMT magnetic bearing systems also feature uninterruptible power supplies (UPS) and backup capacitors, providing sufficient power to maintain rotor suspension during sudden power loss until safe shutdown, preventing equipment damage from rotor drops.

 

High-Precision Displacement Sensing and Position Control——Magnetic bearing suspension precision depends on displacement sensor precision and control system response speed. NMT magnetic bearings use high-resolution eddy current displacement sensors or inductive displacement sensors with resolution up to 0.1μm and sampling frequencies above 50kHz. Sensors and controllers use high-speed digital communication with minimal transmission delay. Controllers support multiple control algorithms——PID, robust control, adaptive control, sliding mode control, etc., with optimal selection based on specific operating conditions. NMT provides complete system calibration and commissioning services to ensure optimal suspension precision and dynamic response on-site. Validated through rigorous precision testing, NMT magnetic bearings maintain rotor orbit control within ±2μm at rated speeds and loads, providing a solid foundation for ultra-precision machining and high-precision measurement.

 

Vacuum and Clean Environment Adaptability——Magnetic bearings require no lubricating oil, have no mechanical wear and generate no particulate contamination, making them ideal for vacuum and clean environments. NMT magnetic bearing electromagnet coils use vacuum-compatible insulating materials, with sensors and connecting cables vacuum-degassed to meet 10⁻⁶Pa ultra-high vacuum requirements. Heat generation in vacuum environments can only dissipate through radiation and conduction, with NMT providing optimized thermal management designs——water cooling channels, thermal radiation shielding and low-power designs for long-term stable operation in vacuum. The oil-free and particle-free characteristics of magnetic bearings make them the preferred bearing solution for semiconductor manufacturing, vacuum coating, space science and other applications.

 

Why Choose NMT Magnetic Bearings?

 

Compared to conventional rolling bearings and industry-standard magnetic bearings, NMT magnetic bearings offer distinct advantages:

 

Active magnetic suspension closed-loop control for non-contact rotor-stator suspension

 

Displacement sensors + digital controllers + power amplifiers + electromagnet actuators

 

Control cycle frequency tens of thousands of times/second for real-time stable suspension

 

Programmable stiffness and damping with online adjustment for different conditions

 

Non-contact wear-free operation with theoretical life limited only by electronic components

 

No lubricating oil or grease required for oil-free, particle-free, contamination-free operation

 

Supports ultra-high-speed operation above 100,000 rpm

 

Laminated cores and high-conductivity coils for optimized electromagnetic losses

 

Auxiliary bearings + UPS + backup capacitors for emergency power loss protection

 

Displacement sensor resolution 0.1μm with rotor orbit ±2μm

 

Vacuum-compatible design (10⁻⁶Pa) with vacuum degassing

 

Water-cooled/air-cooled heat dissipation for controlled temperature rise

 

Suitable for high-speed motors, centrifugal compressors, turbomolecular pumps, flywheel energy storage, spacecraft attitude flywheels, artificial heart blood pumps

 

Passed ultra-high-speed, precision, vacuum and reliability testing

 

These revolutionary performance advantages establish NMT magnetic bearings as the core precision components for high-speed motors, centrifugal compressors, turbomolecular pumps, flywheel energy storage systems, spacecraft attitude flywheels, artificial heart blood pumps and various ultra-high-speed non-contact rotating equipment.

 

Application Scenarios

 

High-speed centrifugal compressor magnetic bearings

 

Flywheel energy storage system magnetic bearings

 

Turbomolecular pump magnetic bearings

 

High-speed motorized spindle magnetic bearings

 

Spacecraft attitude control flywheel magnetic bearings

 

Artificial heart blood pump magnetic bearings

 

High-speed generators and motors magnetic bearings

 

Semiconductor manufacturing vacuum equipment magnetic bearings

 

Precision Manufacturing

 

Produced strictly according to ISO precision standards and magnetic bearing manufacturing specifications, with zero-defect quality execution, NMT magnetic bearings utilize high-permeability silicon steel sheets and high-conductivity copper materials, processed through precision laminated core manufacturing, precision coil winding and vacuum impregnation, precision displacement sensor assembly, digital controller hardware and software development, precision power amplifier tuning, precision auxiliary bearing assembly, system integration and calibration, suspension precision testing, ultra-high-speed operation testing, vacuum environment adaptability testing and power loss protection testing. Every magnetic bearing system is assembled, tuned and inspected in temperature-controlled ultra-clean workshops, with system precision and reliability strictly controlled—ensuring non-contact, wear-free and maintenance-free reliability.

 

Product Range

 

Radial active magnetic bearings

 

Axial active magnetic bearings

 

Radial-axial combined magnetic bearings

 

Five-degree-of-freedom active magnetic bearings

 

High-speed magnetic bearings

 

Vacuum environment magnetic bearings

 

Custom non-standard magnetic bearing systems

 

Global Industrial Service

 

Japan NMT supplies high-quality magnetic bearings and system solutions to global high-speed rotating equipment manufacturers, vacuum equipment companies, aerospace industry and cutting-edge research institutions. With non-contact wear-free revolutionary precision engineering and long-term stable reliable performance, NMT continuously empowers breakthrough performance limits and maintenance-free operation of global ultra-high-speed non-contact rotating machinery.