Advances in magnetic material, control have contributed to the realization of completely non-contacting relating systems employing magnetic bearings to eliminate the last remaining wear out prone element. Current efforts are being directed more towards reducing the size, weight and complexity of these devices to achieve complete acceptance.The AMB technology has been briefly reviewed including its advantages, components, working principles, cost and performance. Some design and Implementation issues have been also discussed.
The taking into consideration the above advantages, the adoption of magnetic bearings in industry will be more economical, efficient and environment friendly compared to the conventional bearings. The authors believe that AMB systems are still relatively more expensive than conventional mechanical bearings; therefore the massive used of AMB in industries is still prohibitive despite of the many benefits offered. The AMBs will still not completely replace conventional bearings in rotating machinery in the near future. However, AMB can find its place well in a limited volume of high performance rotating machines.
4. TYPES OF MAGNETIC BEARINGS
MAGNETIC
BEARINGS
ACTIVE
MAGNETIC
BEARINGS.
1. Radial AMB
2. Thrust AMB.
3. Cone AMB
PASSIVE
MAGNETIC
BEARING.
ALL ACTIVE
MAGNETIC
BEARINGS
11. LOSSES IN AMBS
COPPER Losses - Stationary parts
IRON Losses - Rotating parts
• Hysteresis Losses
• Eddy Current Losses
RESISTANCE Losses
AMPLIFICATION Losses
12. ADVANTAGES
No wear due to contactless operation.
No lubrication & Contaminants.
Pollution free.
Extremely high speed.
Wide range of operating temp.
(– 2500 deg C to 2200 deg C)
Less vibrations due to precise control.
14. APPLICATIONS
High precision position stages.
100,000 rpm milling spindle
Pulp refiner
Smart Aero Engines.
Turbo machines.
Gears, Chains, Conveyors etc.
Energy Storage Flywheels.
Variable speed spindles.
Refrigeration compressor
15. CONCLUSION
The taking into consideration the above advantages, Magnetic
bearings in industry will be more economical, efficient and
environment friendly compared to the conventional bearings. But AMB
systems are still relatively more expensive, therefore the massive use of
AMB in industries is still prohibitive despite of the many benefits
offered.
The AMBs will still not completely replace conventional
bearings in rotating machineries in the near future. However, AMB can
find its place well in a limited volume of high performance rotating
machines.
16. REFERENCES
• “G. van Schoor, A.C. Niemann, C.P. du Rand”, “Evaluation of demodulation
algorithms for robust self-sensing active magnetic bearings”, “147 August 2012’
• “M. Aenis, E. Knopf, R. Nordmann”, “Active magnetic bearings for the
identification and fault diagnosis in turbomachinary” “year 2002”
• “S.C. Mukhopadhyay, C. Gooneratne and G. Sen Gupta”, “Magnetic Bearing: An
Integrated Platform for Teaching and Learning”, “2nd International Conference on
Autonomous Robots and Agents December 13-15, 2004”
• “Gerhard Schweitzer” “Applications and Research Topics for Active Magnetic
Bearings” “Proc. IUTAM-Symp. on Emerging Trends in Rotor Dynamics, March
23-26, 2009, Indian Institute of Technology, Delhi, India. Springer-Verlag”
• Mechanical Engineering – Volume111/No.12 – Eisenberg B.