Magnetic bearings support a load using magnetic levitation rather than physical contact, reducing friction and wear. They consist of electromagnets, position sensors, and a controller to levitate the rotating shaft. Active magnetic bearings use electromagnets and external power, while passive ones use permanent magnets without external power. Applications include maglev trains, compressors, and artificial hearts due to their ability to operate at high speeds and in vacuums or high temperatures with minimal friction.

1. Magnetic bearings

2. Bearings
 Bearings are machine elements which constrains
the relative motion to only desired motion and
reduces friction between the moving parts
 The word “bearing” from the word “to bear” is
a machine element that allows one element to
bear another

3. Magnetic bearings
 A magnetic bearing is
a bearing that
supports a load using
magnetic levitation
 These bearings
doesn’t have any
physical contact
with the moving
parts

4. Magnetic bearings
 They levitate the
rotating shaft and
permit relative motion
with very low friction
 They have minimum
mechanical wear and
support highest speeds
when compared with all
other bearings
 They work effectively
than all other bearings
@ vacum and at high
temperatures

5. Parts of a magnetic bearings:
 An electromagnet assembly
 Power amplifiers- supplies current to the
electromagnetic system
 Gap sensors - electronic circuit which provide
required feedback to control the position of
position of rotor within the gap
 A controller – controls the rotor motion within the
gap

6. Parts of magnetic bearing :

8. Types of magnetic bearings :
Active magnetic bearings Passive magnetic bearings
 Uses electro magnets
for magnetic levitation
 Carries varying load
 Requires input power
supply
 Easy to design
 More effective
 Uses permanent magnet
for magnetic levitation
 Carries static load
 Doesn’t require any
input supply
 Difficult to design
 Less effective

9. Applications of magnetic bearings :
Has several industrial applications due to very
low friction and ability to run without
lubrication
Several applications of magnetic bearings are
 watt-hour meters
 Maglev trains
 Centrifugal compressors
 Artificial hearts

10. Synchrony novaglide
 High temperature active magnetic bearings used
for aerospace and defence applications
 Designed for using in next generation gas turbine
engines where high temperature and high
rotational speeds are already prevailing
 They have optimized magnetic structure which
reduces bearing size
 Can operate at a temperature range of -70 F to 500
F

11. Parts of a novaglide system
 Two radial bearings
each with a stator
and a rotor
 One thrust bearing
 Position sensors
 Magnetic bearing
controller
 Uninterruptible
power supply i.e., a
battery backup
 Auxillary bearings
and bushings
 Cables from
controller to the
bearing

12. Applications of novaglide
 High speed
compressors in large
refrigeration systems
 Expansion turbines
 Gas turbines
 High speed
generators
 Motors as a prime
mover

13. Zippe type centrifuges
 A centrifuge designed to enrich the rare fissile
uranium isotope uranium-235 from the
mixuture of nature uranium containing u-238
 This was first designed in Russia after world
war 2
 For isotopic seperation the centrifuge must
rotate at a very high speed at about 90000 rpm
 The shaft of the high speed rotor is supported by
means of an active magnetic bearing

14. Design of zippie type centrifuge
 Hollow cylindrical rotor
filled with gaseous
uranium
 The magnetic field created
at the bottom by means of
supportive magnetic
bearings enables the rotor
to rotate at a high rpm
without any frictional
loss
 The rotor spins in vacum

15. Artificial heart
 A mechanical device
that replaces heart
 Artificial hearts
bridge the time
during heart
transplantation

17. Design and parts of artificial heart :
 A centrifugal pump provided with magnetic
bearings or a similar axial flow pump can be
used as a artificial heart
 Artificial heart uses magnetic bearings as they
have very less mechanical wear
 The pump can regulate both pulmonary and
systemic circulation
 The centrifugal pump can produce continuous
output

18. Material selection for artificial heart
 The material must
be flexible non toxic
and must bear
various stresses
 The most commonly
used material are
silicones