This presentation describes about the basic working and application of magnetic Bearing.

1. MAGNETIC LEVITATION
PRECAP…………
• Introduction
• Summary
• Theorem related to its principle
• Uses and its Practical Application
Prepared By:
13BEE110 SHETHNA VASAV
13BBEE111 SHINGALA
TUSHAR
Guided by:
Prof. Hormaz
Amrolia

2. Magnetic levitation, maglev
or magnetic suspension is
a method by which an
object is suspended with
no support other than
magnetic fields
Magnetic Levitation

3. Levitation and
Suspension
Levitation:
Force of
Repulsion
Suspension:
Force of
Attraction

4. APPLICATION OF MAGLEV
• Magnetic Bearing
• Maglev Train
• Maglev wind turbine
• Maglev Fan
• StartRam
• Flying Car
• Flywheels

5. Area of Attraction
As a means of
eliminating
friction or
physical contact
Frictionless
bearings
High speed
Ground
Transportation

6. Magnetic
Bearing

7. MEANING OF BEARING
• A bearing is a device that is used to enable
linear or rotational motion of the shaft
while reducing friction.
• It provides stability to the rotating shaft
and frictionless rotation of the same.
• The contacting surfaces in a bearing may
be partially or completely separated by a
film of oil or any other liquid in order to
reduce friction.

8. TYPES OF BEARING
 Plain or slider bearing : -
 In which the rotating shaft has a sliding contact with the bearing which
is held stationary . Due to large contact area friction between mating
parts is high requiring greater lubrication.
 Rolling or anti-friction bearing : -
 Due to less contact area rolling friction is much lesser than the sliding
friction , hence these bearings are also known as antifriction
bearing.

9. MAGNETIC BEARING
• A magnetic bearing system supports a
rotating shaft, without any physical contact
by suspending the rotor in the air, with an
electrically controlled magnetic force.
• It works on the basic principle of Magnetic
Levitation and Electromagnetism.
• We can call it as the future for upcoming
generation of motors.

10. CONTINUE….
• Hence we can say Magnetic bearings
are designed to support rotating and
linear moving machinery elements
without contact with rotor, this is
accomplished by Electro-magnet
(bearing) which attracts a
Ferromagnetic material (rotor) , using
this principle rotor can be suspended in
magnetic field which is generated by
bearing.
• Main components of magnetic bearing
are Actuators, Sensors and Control
Mechanism.

11. Classification of
Magnetic Bearing
Based
on
Control
action
Based on
Forcing
action
Based on
Load
supported
Based on
Magnetic
Effect

12. ACTIVE MAGNETIC BEARING (AMB)
• Because of Earnshaw’s Theorem it is not
possible to use permanent magnets in
magnetic bearing. Even techniques that
deal with diamagnets are under-developed.
• Hence electromagnets are used for
magnetic bearing. Hence magnetic bearing
requires a continuous power input &
control system to stable the load. Even
back-up powering is required in case of
power failure.

13. An Active Magnetic Bearing (AMB)
consists of an electromagnet
assembly, a set of power
amplifiers which supply current
to the electromagnets, a
controller, and gap sensors with
associated electronics to
provide the feedback required to
control the position of the rotor
within the gap.
The power amplifiers supply equal
bias current to two pairs of
electromagnets on opposite
sides of a rotor.
OPERATION
Gap

14. • The controller offsets the required bias current by equal
but opposite perturbations of current as the rotor
deviates by a small amount from its center position.
• The gap sensors are usually inductive in nature and
continuously sensing the gap between rotor and the
bearing.
• The sensor measures the position of the body. The
control electronics then calculates the right current to
suspend the ball.
• This current is set by the amplifier. The resulting force is
within limits proportional to the square of the current
and inversely proportional to the square of the position.
• F = (𝐼/𝑋)^2
• Controller uses Microprocessor to allow the whole
system function in a stable manner.

15. Digital Control System:
A-D Convertor
Control Algorithm
Processor
D-A Convertor
e.g. the position, is sampled. The data
serves as input of the control algorithm,
which runs on the processor. Then the
calculated desired value is converted into
an analog form. According to the
application the data width lies between
10 and 64 bits.

16. APPLICATION
• Turbo-blower: cooling gas
compressor (CO2) for a power laser,
cutting metal sheets up to 25 mm.
The laser needs uncontaminated gas.
• The speed is 54000 rpm, the rotor
mass 3.6 kg, the motor power 12 kW.

17. CONTINUE………..
• Gas-turbine/Generator for power
generation: 4 radial bearings and 1
thrust bearing, 6010 rpm, 9000 kW,
bearing diameter 400 mm.

18.  Magnetic Bearings are free of contact and can be
utilized in vacuum techniques, clean and sterile
rooms, transportation of aggressive media or pure
media.
 Highest speeds are possible even till the ultimate
strength of the rotor.
 Absence of lubrication seals allows the larger and
stiffer rotor shafts.
 Absence of mechanical wear results in lower
maintenance costs and longer life of the system.
ADVANTAGES

19. DISADVANTAGES
High Cost
Relatively
Large
Size

20. PASSIVE MAGNETIC BEARING
(PMB)
• Passive Magnetic Bearing differs
from AMB in terms of magnets
and electronic system.
• The rotor is stabilized only by
permanent uncontrolled
magnetic fields.
• Because of this PMB are less
expensive then AMB.

21. BACKGROUND
• PMB can be constructed using:
 Permanent magnets
 Ferrofuilds(A liquid that gets strongly
energized under magnetic field)
 Diamagnetic materials eg copper, gold,
quartz, mercury, water, alcohol.
• Shown Prototype is built at GLENN
RESEARCH CENTER.

22. PROTOTYPE
• A prototype has been realized. Levitation is
assured by a 7 cm graphite disc and a 2D
array assembled of 5mm cubic NdFeB
magnets. Weight compensation uses a
cylindrical magnet of Ø 5 mm placed on the
rotor and a ferromagnetic counterpiece on
the stator (2).
• The rotor mass is 92 grams and it levitates
at 300μm.

23. PROTOTYPE FIGURE

25. • As far as the application is
concerned it is limited as the
diamagnetic or the permanent
magnets can be damaged easily.
• It can only be used in application of
flywheels.
• First PMB bearing was prepared at
GLENN RESEARCH CENTER at the
speed of 5500rpm.
Application of PMB

26. Disadvantages
Permanent
Magnets are
used
Hence not
economical
Gets Damaged
Easily Due to heat
or some other
Factor

27. • Used in industrial machines like compressors,
turbines, pumps, motors and generators.
• Can be used in Watt-Hour Meter to measure home
power consumption.
• Useful in high precision equipment & to support
equipment in a vacuum.
• To support Maglev Trains for smooth & noise free
ride.
• Useful in ARTIFICAL HEART.
• Anywhere where ROTATING part is used……………
APPLICATIONS Of
MAGNETIC BEARING

28. REFERENCES
• Introduction to magnetic bearing by JAGU
SRINIVASA RAO (Pdf)
• Magnetic Bearings by HILLYARD (Pdf)
• Design and Control of Active Magnetic Bearing
Systems for High Speed Rotation by RENE
LARSONNEUR (Pdf)
• PMB by Gerhard Schweitzer (PDF)
• Optimization of Repulsive Passive Magnetic
Bearings Roland Moser, Jan Sandtner, and
Hannes Bleule1.