ISO 14839-1:2018 機械的振動—アクティブ磁気軸受を備えた回転機械の振動—パート1：用語, 語彙 | ページ 5

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.

3.1.4

passive magnetic bearing

means of supporting a rotor, without mechanical contact, using magnetic forces without feedback control

3.1.5

permanent magnetic bearing

PMB

passive magnetic bearing (3.1.4) using one or several pairs of permanent magnets without feedback control

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

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

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_r in Figure 3 for radial AMB, and δ_a in Figure 4 for axial AMB.

3.1.12

clearance centre of a radial AMB

geometric centre of a radial bearing stator

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)

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

3.1.23

effective length of a radial magnetic bearing

pole face axial length of a radial bearing stator for which the radial electromagnet is able to generate an attractive force exerted on the rotor

3.1.24

projection area of a radial AMB

product dL of the radial bearing journal diameter (3.2.3) , d, and the effective bearing length, L

Note 1 to entry: See Figure 3.

3.1.25

area of one magnetic pole

cross-sectional area, A, of a magnetic pole which can generate an attractive force exerted on the rotor

Note 1 to entry: This is different from the projection area as defined in 3.1.24.

Note 2 to entry: See A_r in Figure 3 for radial AMB, and A_a in Figure 4 for axial AMB.

3.1.26

load capacity of an AMB

maximum force that an AMB (3.1.3) can generate on the rotor at its fixed centred position

Note 1 to entry: This is usually limited by the magnetic saturation of the ferromagnetic material of stator and rotor core, the maximum coil current available from the power amplifier (3.5.3) that drives the magnetizing coil (3.3.4) and the maximum driving voltage of the power amplifier.

3.1.26.1

static load capacity of an AMB

F_max

maximum load capacity for constant load over an unlimited time period of continuous operation

3.1.26.2

peak transient load capacity of an AMB

maximum load capacity over a limited time period

3.1.26.3

dynamic load capacity of an AMB

maximum allowed amplitude value for a periodic force generated by an AMB (3.1.3) as a function of frequency

3.1.27

load pressure of a radial AMB

3.1.28

number of control axes of an AMB

number of degrees of freedom of the rotor motion which are controlled by the AMB (3.1.3)

3.1.29

total AMB loss

sum of iron loss due to eddy currents and hysteresis in the rotor and the stator, copper loss (ohmic loss) in coils, windage loss on the bearing rotor surface and circuit loss in the electrical equipment (cable, electronic cabinet)

3.1.30

self-sensing AMB

active magnetic bearing (3.1.3) which includes the function of rotor position detection without the use of direct displacement transducers (3.4.3)

3.1.31

rise time

time required for an AMB (3.1.3) force to change from 10 % to 90 % of the peak transient load capacity (3.1.26.2)

3.1.32

dwell time

time that the peak transient force can remain at the peak level

3.1.33

non-collocation

situation in which radial transducers and electromagnets are not placed at the same axial location

Note 1 to entry: Figures 3 and 4 show the typical cases, and non-collocation often affects the plant dynamics.

3.1.34

coaxiality

geometric line positioning characteristic between AMB (3.1.3) and touch-down bearing (3.6.1) as well as between the AMBs

Note 1 to entry: Coaxiality is explained in ISO 1101.

3.1.35

concentricity

geometric point positioning characteristic between AMB (3.1.3) and touch-down bearing (3.6.1) as well as between the AMBs

Note 1 to entry: Concentricity is explained in ISO 1101.

3.2.1

radial rotor core

radial rotor journal

ferromagnetic portion of the rotating shaft on which the radial magnetic control forces are exerted, which is typically laminated

3.2.2

axial bearing disc

axial disc

axial rotor disc

thrust bearing disc

thrust disc

thrust rotor disc

ferromagnetic portion of the rotating shaft on which the axial magnetic forces are exerted

3.2.3

journal diameter

diameter of the radial magnetic bearing (3.1.9) rotor

Note 1 to entry: See d in Figure 3.

3.2.4

geometrical runout

mechanical runout

measured fictitious displacement of the rotating shaft due to the effect of the non-circularity and non-coaxiality of the shaft shape

3.2.5

electrical runout

position transducer runout

measured fictitious displacement of the rotating shaft due to the magnetic or electrical non-homogeneity of the position transducer target (3.4.6)

3.2.6

DN value

product dN of the diameter d (mm) and the rotor speed N (r/min)

3.3.1

stator core

core of the stationary AMB (3.1.3) components made of ferromagnetic or other magnetically permeable materials

3.3.2

radial stator core

stationary section of the radial magnetic bearing (3.1.9) around which the magnetizing coil (3.3.4) is wound

3.3.3

axial stator core

thrust stator core

stationary section of the axial magnetic bearing (3.1.10) around which the magnetizing coil (3.3.4) is wound

3.3.4

magnetizing coil

coil used to generate the magnetic flux in the core material

3.3.5

radial coil

magnetizing coil (3.3.4) wound around the core of the radial bearing or the radial electromagnetic pole itself

3.3.6

axial coil

thrust coil

magnetizing coil (3.3.4) of an axial AMB (3.1.3)

3.3.7

allowed operating temperature

coil and lamination temperatures which allow for specified normal AMB (3.1.3) operation

3.4.1

position measuring system

composition of devices comprising a sensor that responds to changes in the rotor/stator gap, an amplifier to excite the sensor and apply a gain to the response signal, and a signal post processing unit

3.4.2

shaft displacement

rotor centre displacement in the radial or axial direction measured from the nominal position, indicating a change of rotor position

Note 1 to entry: Shaft displacement is sometimes called shaft vibration, shaft movement or shaft motion.

3.4.3

displacement transducer

position transducer

transducer for the detection of shaft position without any mechanical contact

Note 1 to entry: See Figures 3 and 4.

3.4.4

radial displacement transducer

radial position transducer

transducer for the detection of radial shaft position

Note 1 to entry: See Figures 3 and 5.

3.4.5

axial displacement transducer

axial position transducer

thrust displacement transducer

thrust position transducer

transducer for the detection of axial shaft position

Note 1 to entry: See Figure 4.

3.4.6

transducer target

area of rotating shaft where the position transducer (3.4.3) detects the displacement

Note 1 to entry: See Figures 3 and 4.

3.4.7

radial transducer target

radial target

area of rotating shaft where the radial position transducer (3.4.4) detects the displacement in the radial direction

Note 1 to entry: See Figure 3.

3.4.8

axial transducer target

axial target

area of rotating shaft where the axial position transducer (3.4.5) detects the displacement in the axial direction

Note 1 to entry: See Figure 4.

3.5.1

AMB system

system consisting of a rotor, position transducers (3.4.3) or other means to detect rotor position, controller(s), power amplifiers (3.5.3) and electromagnets to levitate and support the rotor by attractive magnetic forces

Note 1 to entry: See Figures 2 and 11.

3.5.2

AMB controller

device which detects and processes the transducer signal and transfers it to the power amplifier (3.5.3) in order to regulate the magnetic attractive force to levitate the rotor

3.5.3

power amplifier

power output device which generates magnetizing coil (3.3.4) current in order to generate a magnetic control force

3.5.4

AMB current control

method of controlling AMB (3.1.3) using voltage input/current output power amplifiers (3.5.3) for the feedback actuator from power amplifier to electromagnetic current

3.5.5

AMB voltage control

method of controlling AMB (3.1.3) using voltage input/voltage output power amplifiers (3.5.3)

3.5.6

AMB bias current

I₀

fixed d.c. coil current used to linearize the attractive force in relation to the current and the clearance of the AMB (3.1.3)

Note 1 to entry: See formulae in Figure 10.

3.5.7

negative position stiffness

K_s

<in the bias-linearized AMB actuator> position stiffness of the electromagnet due to bias current (3.5.6) at the nominal rotor position without an external load

Note 1 to entry:K_s is negative.

Note 2 to entry: See Figures 10 and 11.

3.5.8

closed-loop dynamic system stiffness

transfer function(s) of the F_d/X ratio of the AMB(s) (3.1.3) closed-loop system with the disturbance input force F_d and output displacement X

Note 1 to entry: See Figure 11.

3.5.9

closed-loop dynamic system compliance

reciprocal of the closed-loop dynamic system stiffness (3.5.8) , i.e. X/F_d

Note 1 to entry: See Figure 11.

3.5.10

open-loop AMB dynamic stiffness

transfer function of the F_b/X ratio of the AMB (3.1.3) open-loop system with the displacement input X and the bearing output force F_b, through the transducer, controller, power amplifier (3.5.3) and electromagnet

Note 1 to entry: The frequency-dependent bearing spring force is obtained by the real part of the complex ratio F_b/X, and the frequency-dependent bearing damping force is obtained by the imaginary part of the complex ratio F_b/X.

Note 2 to entry: See Figure 11.

3.5.11

AMB centralized control

control structure that has internal connections between the controller inputs and controller outputs for different degrees of freedom of the rotor

3.6.1

touch-down bearing

bearing installed in the AMB system (3.5.1) , which is designed to limit the rotor motion and to prevent contact with the AMB stator or rotor surface due to overload, failure or deactivation of the AMB system

Note 1 to entry: Other designations include auxiliary bearing, back-up bearing, catcher bearing, emergency bearing and retainer bearing.

3.6.2

touch-down bearing clearance

half of the difference between the inner diameter of the touch-down radial bearing bore and the outer diameter of the rotor shaft, or the axial clearance between the thrust face of an axial touch-down bearing (3.6.1) and the shaft shoulder

Note 1 to entry: These touch-down bearing clearances need to be smaller than the gap between the rotor and stator in the AMB system (3.5.1) .

Note 2 to entry: For radial clearance of touch-down bearing, see key 3 in Figure 5 or Figure 6.

3.6.3

touch-down test

test where a rotor rotating at the designated speed is dropped intentionally on the touch-down bearings (3.6.1) in order to evaluate their performance

Note 1 to entry: Other designations include drop test, landing test, back-up bearing test.

3.6.4

uninterruptible power supply system

UPS system

source of stored energy that can be used to power the AMB system (3.5.1) during a mains power supply failure

3.6.5

touch-down bearing compliant mount

flexible element which provides a defined stiffness and damping support for a mounted radial touch-down bearing (3.6.1)

Note 1 to entry: This support is required in order to improve vibration response when running on touch-down bearings.

3.6.6

touch-down bearing hard-stop clearance

travel distance to a hard stop which limits the movement of the compliant mount of a radial touch-down bearing (3.6.1)