ISO 14839-1:2018

INTERNATIONAL ISO
STANDARD 14839-1
Second edition
2018-10
Mechanical vibration — Vibration of
rotating machinery equipped with
active magnetic bearings —
Part 1:
Vocabulary
Vibrations mécaniques — Vibrations de machines rotatives équipées
de paliers magnétiques actifs —
Partie 1: Vocabulaire
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms . 1
3.2 Terms relating to rotors .10
3.3 Terms relating to stators .10
3.4 Terms relating to position transducers .11
3.5 Terms relating to dynamics, control and electronics .13
3.6 Terms relating to auxiliary equipment .17
Bibliography .19
Alphabetical index .20
Foreword
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This document was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and
condition monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock
as applied to machines, vehicles and structures.
This second edition cancels and replaces the first edition (ISO 14839-1:2002), which has been technically
revised. It also incorporates the Amendment ISO 14839-1:2002/Amd. 1:2010.
The main change compared to the previous edition is as follows:
— the terms have been updated and revised to reflect how they are used in practice.
A list of all parts in the ISO 14839 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 14839-1:2018(E)
Mechanical vibration — Vibration of rotating machinery
equipped with active magnetic bearings —
Part 1:
Vocabulary
1 Scope
This document defines terms relating to rotating machinery equipped with active magnetic bearings.
NOTE General terms and definitions of mechanical vibration are given in ISO 2041; those relating to
balancing are given in ISO 21940-2; those relating to geometric characteristics such as coaxiality, concentricity
and runout are explained in ISO 1101.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1 General terms
3.1.1
levitation
maintaining the position of a rotor by attractive or repulsive magnetic forces without mechanical contact
3.1.2
magnetic bearing
bearing which utilizes either attractive or repulsive magnetic forces for the levitation (3.1.1) and
dynamic stabilization of a rotor
3.1.3
active magnetic bearing
AMB
means of supporting a rotor, without mechanical contact, using only attractive magnetic forces based
upon servo feedback technology which normally consists of transducers, electromagnets, power
amplifiers (3.5.3), power supplies and controllers
Note 1 to entry: For rotating machinery equipped with active magnetic bearings, the graphical symbols for
bearings are shown in Figure 1.
Note 2 to entry: The principle of an active magnetic bearing is shown in Figure 2.
Key
1 angular ball bearing 5 thrust bushing
2 deep groove ball bearing 6 radial active magnetic bearing
3 thrust ball bearing 7 axial active magnetic bearing
4 radial bushing
a
With transducer.
Figure 1 — Graphical symbols for bearings
Key
1 controller 4 power supply
2 power amplifier 5 rotor
3 electromagnet 6 displacement transducer
Figure 2 — Principle of active magnetic bearing
3.1.4
passive magnetic bearing
means of supporting a rotor, without mechanical contact, using magnetic forces without feedback control
EXAMPLE Permanent magnetic bearing (3.1.5), super-conducting magnetic bearing (3.1.6).
3.1.5
permanent magnetic bearing
PMB
passive magnetic bearing (3.1.4) using one or several pairs of permanent magnets without feedback control
2 © ISO 2018 – All rights reserved

3.1.6
super-conducting magnetic bearing
SMB
passive magnetic bearing (3.1.4) using a pair of (high-temperature) super conductors and permanent
magnets without feedback control, utilizing the so-called pinning force (attractive and repulsive forces)
3.1.7
hybrid magnetic bearing
HMB
bearing consisting of any combination of an active magnetic bearing (3.1.3) and passive magnetic
bearing (3.1.4)
3.1.8
permanent-magnet-biased AMB
active magnetic bearing (3.1.3) in which the nominal (non-zero) or bias magnetic fluxes are established
by one or more permanent magnets
3.1.9
radial magnetic bearing
magnetic bearing (3.1.2) which levitates a rotor in the radial direction and supports it against
disturbances in the radial direction, such as unbalance forces, fluid forces or gravity
Note 1 to entry: See Figure 3.
Key
1 radial coil D inner diameter of radial stator core
2 radial transducer d outer diameter of radial rotor core
3 radial transducer target δ nominal magnetic gap (D − d)/2
r
4 radial rotor core L total bearing length (including coil windings)
t
5 axial centre of radial AMB L effective length of radial bearing
6 radial stator core W width of a magnetic pole
7 shaft A area of magnetic pole (A = WL)
r r
Figure 3 — Radial AMB assembly
3.1.10
axial magnetic bearing
thrust magnetic bearing
magnetic bearing (3.1.2) which levitates a rotor in the axial direction and supports it against
disturbances in the axial direction, such as fluid forces or gravity
Note 1 to entry: See Figure 4.
Key
1 rotor d outer diameter of axial rotor disc
a
2 axial transducer target D outer diameter of outer pole of axial stator
o
3 axial transducer d inner diameter of outer pole of axial stator
o
4 axial stator core d outer diameter of inner pole of axial stator
i
5 axial coil D inner diameter of inner pole of axial stator
i
6 (clearance) centre of axial AMB δ nominal magnetic gap
a
7 axial rotor disc A area of the magnetic pole pair
a
π
22 22
AD=−dd+−D
()
ao oi i
Figure 4 — Axial AMB assembly
3.1.11
nominal magnetic gap
distance between the magnetic materials of the rotor and the stator inside the AMB (3.1.3) when the
journal centre of the rotor is located in the clearance centre of the bearing stator
Note 1 to entry: See δ in Figure 3 for radial AMB, and δ in Figure 4 for axial AMB.
r a
3.1.12
clearance centre of a radial AMB
geometric centre of a radial bearing stator
Note 1 to entry: See Figure 5.
4 © ISO 2018 – All rights reserved

Key
1 axial centre of radial AMB 7 radial transducer target
2 magnetic gap of radial AMB 8 touch-down bearing
3 radial clearance of touch-down bearing 9 radial centre offset between radial touch-down
bearing and AMB centre
4 journal (rotor) centreline of radial AMB
5 clearance centreline of radial AMB 10 radial centre of radial touch-down bearing
6 radial transducer
NOTE Similar consideration applies to a radial homopolar AMB.
Figure 5 — Centres and centrelines of radial heteropolar AMB
3.1.13
magnetic centre of a radial AMB
position of a rotor in a radial AMB (3.1.3) at which the net radial attractive forces exerted on the rotor
go to zero for nominal currents or fluxes, and without any magnetic excitation or compensation forces
3.1.14
axial centre of a radial AMB
axial directional position of geometric centre of stator core (3.3.1)
Note 1 to entry: See Figure 5.
3.1.15
clearance centre of an axial AMB
clearance centre of a thrust AMB
axial position of the geometric centre of an (axial) thrust AMB (3.1.3) stator
Note 1 to entry: See Figure 4.
3.1.16
axial magnetic centre of an axial AMB
position of an axial rotor disc (3.2.2) in an axial AMB (3.1.3) at which the net axial attractive forces
exerted on the rotor disc go to zero for nominal currents or fluxes, and without any magnetic excitation
or compensation forces
3.1.17
clearance centreline of a radial AMB
line between the clearance centres of two radial AMBs (3.1.3) specified by the bearing stator
configuration
Note 1 to entry: See Figure 5.
3.1.18
journal centreline of a radial AMB
geometric centreline between the journal centres of a radial AMB (3.1.3) rotor
Note 1 to entry: See Figure 5.
3.1.19
bearing span between radial AMBs
axial distance between the axial centres of two radial AMBs (3.1.3)
Note 1 to entry: See Figure 6.
Key
1 bearing span between radial AMBs
2 magnetic radial clearance of radial AMB
3 radial clearance of touch-down bearing
4 axial clearance of touch-down bearing
Figure 6 — Heteropolar-type radial AMB
3.1.20
number of poles
sum of the south and north magnetic gap poles of an AMB (3.1.3)
Note 1 to entry: See Figure 7.
3.1.21
heteropolar-type radial AMB
radial AMB (3.1.3) in which the electromagnetic cross section has poles of different polarity, and the
poles may have different polarity arrangements
Note 1 to entry: Polarity arrangements can be (N, S, N, S, .), (N, S, S, N, .), etc.
Note 2 to entry: See Figure 7 a).
3.1.22
homopolar-type radial AMB
radial AMB (3.1.3) whose electromagnet has more than one axial cross section, each having poles of a
single polarity
Note 1 to entry: See Figure 7 b).
6 © ISO 2018 – All rights reserved

a)  Heteropolar type (8 poles) b)  Homopolar type (8 poles)
Key
X, Y control axes
Figure 7 — Number of poles of radial AMB
3.1.23
effective length of a radial magnetic bearing
pole face axial length of a radial bearing stator for whi
...