1. “DESIGN OF ACTIVE MAGNETIC BEARING”
Presented By
JADHAV MANORANJAN A.
Guided By
Prof . S. B. BELKAR

2. Introduction
Magnetism Magnetic field

3. Magnetism Magnetic Flux Density
multiple loops of wire, n
B = magnetic flux density
= magnetic permeability
H = magnetic field
m0 = permeability of free space
mr = relative permeability
diamagnetic
paramagnetic
ferromagnetic

4. Magnetism Magnetic Field
Magnetic field, H, is found around a magnet or a current carrying body. H i
(for one current loop)

5. Magnetism Lorentz Force
f = force
Q = electric charge
E = electric field
V = velocity of charge Q
B = magnetic flux density

6. Magnetism Lorentz Force
Simplification:
Source: MIT Physics Dept. website

7. Magnetism Lorentz Force
Analogous Wire
Further simplification: B i f
force perpendicular to flux!

8. MAGNETIC BEARING
Bearing which supports a load using magnetic levitation
Advantages of magnetic bearings:
contact-free
no lubricant
(no) maintenance
tolerable against heat, cold, vacuum, chemicals
low losses
very high rotational speeds
Disadvantages:
complexity
high initial cost

9. MAGNETIC BEARING TYPES
PASSIVE MAGNETIC BEARING
Not electrically controlled,
Permanent magnets
ACTIVE MAGNETIC BEARING
Electrically controlled,
Electromagnets

10. Model of Active Magnetic Bearing
Principle of operation: Magnetic Levitation

11. Active Magnetic Bearings Elements of System
Electromagnet
Rotor
Stator
Position Sensor
Controller
Amplifier

12. Radial Bearing Configuration:
for radial force balancing
Axial Bearing Configuration:
for axial force balancing
Position Transducers:

13. Auxiliary Bearing System

14. Control system:
Sensors
Controller
Power Amplifiers

15. Principle of radial and axial force  
Where ,

16. magnetic flux in the air gap

17. permeances of bias & axial control fluxes Pb & Px
The axial force

18. Analysis of AMB system using Finite Element Method

19. Performance relative to hydrodynamic bearing
REQUIREMENTS
MAGNETIC BEARING
HYDRODYNAMIC BEARING
High loads
low
high
Speed
Sealing
Not required
required
Unbalance no
yes
Losses
Very low

20. ADVANTAGES OF AMB NON CONTACT MOTION HIGH ROTATING SPEED
NO LUBRICATION
INCREASE IN OPERATING TEMPERATURE RANGE
ACTIVE NATURE

21. DISADVANTAGES OF AMB
NO LINEARITY
ROTOR HEATING
LARGER SIZE
HIGH COST

22. APPLICATIONS OF AMB Image display unit High precision lathe
Turbo expander
Turbo compressor
High speed milling
Machine tool spindle
Maglev Trains

23. Applications Maglev Trains
Maglev = Magnetic Levitation
150 mm levitation over guideway track
undisturbed from small obstacles (snow, debris, etc.)
typical ave. speed of 350 km/h (max 500 km/h)
what if? Paris-Moscow in 7 hr 10 min (2495 km)!
stator: track, rotor: magnets on train
Source: DiscoveryChannel.com

24. Applications Maglev Trains
Maglev in Shanghai
- complete in 2004
- airport to financial district (30 km)
- world‘s fastest maglev in commercial operation (501 km/h)
- service speed of 430 km/h
Source:

25. THANK YOU