Joint Advanced Student School2006
Jeff Hillyard
Technische Universität München
ic Bearings
Overview ic Bearings
Introduction
ism Review
Active ic Bearings
Passive ic Bearings
Industry Applications
Introduction ic Bearing Types
Active/passive ic bearings
electrically controlled
no control system
Radial/axial ic bearings
Introduction Motivations
Advantages of ic bearings:
contact-free
no lubricant
(no) maintenance
tolerable against heat, cold, vacuum, chemicals
low losses
very high rotational speeds
Disadvantages:
complexity
high initial cost
Minimum Equipment for AMB
Source: Betschon
Introduction Survey of ic Bearings
Source: Schweitzer
ism ic Field
north pole
south pole
ic field line
iron filings
Pole Transition
ism ic Field
ic field, H, is found around a or a current carrying body.
(for one current loop)
H
i
ism ic Flux Density
B = ic flux density
= ic permeability
H = ic field
m0 = permeability of free space
mr = relative permeability
ic
ic
ic
multiple loops of wire, n
Meissner-Ochsenfeld Effect
ism B-H Diagram
H
B
area within loop represents hysteresis loss
ic saturation
ic: a material that can be ized
Coercivity, Hc
Remanence, Br
ism Lorentz Force
f = force
Q = electric charge
E = electric field
V = velocity of charge Q
B = ic flux density
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