ISO 2953:1999

Mechanical vibration - Balancing machines - Description and evaluation

Vibrations mécaniques — Machines à équilibrer — Description et évaluation

General Information

• Status: Withdrawn
• Publication Date: 21-Apr-1999
• Withdrawal Date: 21-Apr-1999
• ICS: 21.120.40 - Balancing and balancing machines
• Technical Committee: ISO/TC 108/SC 2 - Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures
• Drafting Committee: ISO/TC 108/SC 2/WG 31 - Balancing
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 10-Jul-2012
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 21940-21:2012 - Mechanical vibration - Rotor balancing - Part 21: Description and evaluation of balancing machines
• Effective Date: 08-May-2010
• Revises: ISO 2953:1985 - Balancing machines - Description and evaluation
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 2953
Third edition
1999-04-15
Mechanical vibration — Balancing
machines — Description and evaluation
Vibrations mécaniques — Machines à équilibrer — Description et
évaluation
A
Reference number
Contents Page
1 Scope .1
2 Normative reference .1
3 Definitions .1
4 Capacity and performance data of the machine.1
4.1 Data of horizontal machines.2
4.2 Data of vertical machines.6
5 Machine features.10
5.1 Principle of operation.10
5.2 Arrangement of the machine .10
5.3 Indicating system.11
5.4 Plane separation system.12
5.5 Setting and calibration of indication.12
5.6 Other devices .13
6 Minimum achievable residual unbalance .13
7 Production efficiency .13
7.1 General.13
7.2 Time per measuring run.14
7.3 Unbalance reduction ratio .14
8 Performance qualifying factors.14
9 Installation requirements .15
9.1 General.15
9.2 Electrical and pneumatic requirements.15
9.3 Foundation .15
©  ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
Printed in Switzerland
ii
© ISO
10 Proving rotors and test masses. 15
10.1 General . 15
10.2 Proving rotors . 15
10.3 Test masses . 17
11 Verification tests. 26
11.1 Requirements for performance and parameter verification. 26
11.2 Duties of manufacturer and user . 26
11.3 Requirement for weighing scale . 27
11.4 Test and rechecks . 27
11.5 Test speed . 27
11.6 Test for minimum achievable residual unbalance (U test) . 27
mar
11.7 Test for unbalance reduction ratio (URR test) . 31
11.8 Test for couple unbalance interference on single-plane machines .40
11.9 Compensator test . 40
11.10 Simplified tests . 41
Annex A (normative) Definitions . 42
Annex B (informative) Information to be supplied to the balancing machine manufacturer by the user . 45
Annex C (informative) URR limit diagrams.49
Annex D (informative) Shafts of outboard proving rotors type C . 52
Annex E (informative) Modification of old (ISO 2953:1985) proving rotors to this International Standard . 54
Annex F (informative) Bibliography. 55
iii
© ISO
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 2953 was prepared by Technical Committee ISO/TC 108, Mechanical vibration and
shock, Subcommittee SC 1, Balancing, including balancing machines.
This third edition cancels and replaces the second edition (ISO 2953:1985). It contains revised and more detailed
recommendations for testing the capability of balancing machines, including outboard proving rotors and overhung
test planes. It replaces the previous edition of this document.
Annex A is an integral part of this International Standard. Annexes B to F are for information only.
iv
INTERNATIONAL STANDARD  © ISO ISO 2953:1999(E)
Mechanical vibration — Balancing machines — Description
and evaluation
1 Scope
This International Standard gives requirements for the evaluation of the performance and characteristics of
machines for balancing rotating components. It stresses the importance attached to the form in which the balancing
machine characteristics should be specified by the manufacturers and also outlines criteria and tests for evaluating
balancing machines. Adoption of the format suggested in 4.1 and 4.2 makes it easier for the user to compare
products of the different manufacturers. Guidance as to the manner in which users should state their requirements
is given in annex B.
Details of proving rotors, test masses and performance tests to be employed to ensure compliance with specified
unbalance indicating capability are given. Tests for other machine capacities and performance parameters are not
contained in this International Standard.
Annex E describes recommended modifications of old ISO proving rotors.
This International Standard does not specify balancing criteria; these are specified in ISO 1940-1.
This International Standard is applicable to balancing machines that support and rotate workpieces which are rigid
at balancing speed, and that indicate the amounts and angular locations of required unbalance corrections in one or
more planes. It covers both the machines that measure out-of-balance effects on soft bearings and those that
measure this on hard bearings.
Technical requirements for such balancing machines are included, however, special features, such as those
associated with automatic correction, are excluded.
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the edition indicated was valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 1925:1990, Mechanical vibration — Balancing — Vocabulary.
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 1925 and those given in annex A apply.
4 Capacity and performance data of the machine
The manufacturer shall specify the data listed in 4.1 for horizontal or 4.2 for vertical machines respectively, as
applicable, and in a similar format.
© ISO
4.1 Data of horizontal machines
4.1.1 Rotor mass and unbalance limitations
4.1.1.1  The maximum mass of rotor which can be balanced shall be stated over the range of balancing speeds.
The maximum moment of inertia [(mass · (radius of gyration) ] of a rotor with respect to the shaft axis which the
machine can accelerate in a stated acceleration time shall be given for the range of balancing speeds (n , n , .)
1 2
together with the corresponding cycle rate (see table 1).
Table 1 — Data of horizontal machines
Manufacturer: . Model.
Balancing speeds or speed ranges (see also 4.1.3.1) n n n n n
1 2 3 4 5
Rotor mass kg maximum
(see note 1) minimum
Occasional overload force per support N
(see note 1)
Maximum negative force per support N
(see note 1)
Maximum rotor moment of inertia with respect to the shaft axis
(see note 2) kg·m
Cycle rate (see note 2)
Maximum unbalance g·mm/kg or g·mm measurable
(see note 3) permissible
a) For inboard rotors
Minimum achievable residual specific unbalance, maximum mass
e , g·mm/kg
mar
(see note 4 and clause 6)
0,2 · max. mass
minimum mass
Corresponding deflection of analog amount-of- maximum mass
unbalance indicator, mm
Number of digital units
(see note 4)
0,2 · max. mass
minimum mass
b) For outboard rotors
maximum mass
Minimum achievable residual specific unbalance,
e , g·mm/kg
mar
(see note 4 and clause 6)
0,2 · max. mass
minimum mass
Corresponding deflection of analog amount-of-
unbalance indicator, mm
maximum mass
Number of digital units (see note 4)
0,2 · max. mass
minimum mass
© ISO
4.1.1.2  Production efficiency (see clause 7) shall be stated, as follows.
4.1.1.2.1  Time per measuring run:
a) Time for mechanical adjustment: . s
b) Time for setting indicating system: . s
c) Time for preparation of rotor: . s
d) Average acceleration time: . s
e) Reading time (including time to stabilize): . s
f) Average deceleration time: . s
g) Relating readings to rotor: . s
h) Other necessary time: . s
i) Total time per measuring run [ a) to h) above]: . s
4.1.1.2.2  Unbalance reduction ratio for inboard rotors: . %
4.1.1.2.3  Unbalance reduction ratio for outboard rotors: . %
4.1.2 Rotor dimensions
4.1.2.1  Adequate envelope drawings of the pedestals and of other obstructions, such as belt-drive mechanism,
shroud mounting pads, thrust arms and tie bars, shall be supplied to enable the user to determine the maximum
rotor envelope that can be accommodated and the tooling and/or adaptors required.
A combination of large journal diameter and high balancing speed may result in an excessive journal peripheral
speed. The maximum journal peripheral speed shall be stated.
When belt drive is supplied, balancing speeds shall be stated for both the maximum and minimum diameters over
which the belt can drive, or other convenient diameter.
The manufacturer shall state if the axial position of the drive can be adjusted.
4.1.2.2  Rotor envelope limitations (see figure 1) shall be stated.
4.1.2.3  Rotor diameter:
a) Maximum diameter over bed: . mm
b) Maximum diameter over which belt can drive: . mm
c) Minimum diameter over which belt can drive: . mm
4.1.2.4  Distance between journal centrelines:
a) Maximum: . mm
b) Minimum: . mm
c) Maximum distance from coupling flange to centreline of farthest bearing: . mm
d) Minimum distance from coupling flange to centreline of nearest bearing: . mm
© ISO
Key
1 Shaft
2 Rotor
3 Support
4 Bed
NOTE 1 If the left-hand support is not a mirror image of the right-hand support, separate dimensions shall be shown.
NOTE 2 The profile of the belt-drive equipment shall be shown, if applicable.
Figure 1 — Example of machine support drawing illustrating rotor envelope limitations
© ISO
Journal diameter:
4.1.2.5
a) Maximum: . mm
b) Minimum: . mm
Maximum permissible peripheral journal speed . m/s
4.1.2.6  Correction plane limitations (consistent with the statements in 5.4) shall be stated.
4.1.2.7  Correction plane interference ratios (consistent with the statements in 5.4 and based on the proving rotor)
shall be stated.
4.1.3 Drive
4.1.3.1  Balancing speed Rated torque on workpiece
r/min N·m
n . .
n . .
n . .
n . .
n . .
n . .
n . .
n . .
or or
steplessly variable steplessly variable
from . .
to . .
4.1.3.2  Torque (see note 5):
a) Zero-speed torque: . % rated torque on workpiece
b) Run-up torque adjustable from . to . % rated torque on workpiece
c) Peak torque . % rated torque on workpiece
4.1.3.3  Type of drive to workpiece (see note 6): .
4.1.3.4  Prime mover (type of motor): .
a) Rated power: . kW
b) Motor speed: . r/min
c) Power supply, voltage / frequency / phase: .
4.1.3.5  Brake
a) Type of brake: .
b) Braking torque adjustable from . to . % of rated torque
© ISO
c) Can brake be used as a holding device? Yes / No
4.1.3.6  Motor and controls in accordance with the following standard(s): .
4.1.3.7  Speed regulation provided:
Accurate or constant within . % of . r/min, or . r/min
4.1.4 Couple unbalance interference ratio (g·mm/g·mm ) . % (see note 7)
4.1.5 Air pressure requirements: . Pa; . m /s
NOTE 1 The occasional overload force need only be stated for the lowest balancing speed. It is the maximum force per
support that can be accommodated by the machine without immediate damage.
The negative force is the static upward force resulting from a workpiece having its centre of mass outside the bearing support.
NOTE 2 Cycle rate for a given balancing speed is the number of starts and stops which the machine can perform per hour
without damage to the machine when balancing a rotor of the maximum moment of inertia.
NOTE 3 In general, for rigid rotors with two correction planes, one-half of the stated value pertains to each plane; for disc-
shaped rotors, the full stated value holds for one plane.
NOTE 4 Limits for soft-bearing machines are generally stated in gram millimetres per kilogram (specific unbalance), since
this value represents a measure of rotor displacement and, therefore, motion of the balancing machine bearings. For hard-
bearing machines, the limits are generally stated in gram millimetres, since these machines are usually factory-calibrated to
indicated unbalance in such units (see clause 6). For two-plane machines, this is the result obtained when the minimum
achievable residual unbalance is distributed between the two planes.
NOTE 5 In most cases, maximum torque is required for accelerating a workpiece. However, in the case of a workpiece with
high windage and/or friction loss, maximum torque may be required at balancing speed. When there is axial thrust, it is
necessary that provisions be made to take this into account.
NOTE 6 Examples of the type of drive to the workpiece are:
 end drive by universal joint driver,
 end drive by band,
 belt drive,
 magnetic field,
 driven bearing rollers,
 air jet, etc.
NOTE 7 This value is only applicable for single-plane balancing machines. It describes the influence of couple unbalance in
the rotor on the indication of static unbalance.
4.2 Data of vertical machines
4.2.1 Rotor mass and unbalance limitations
4.2.1.1  The maximum mass of rotor which can be balanced shall be stated over the range of balancing speeds.
The maximum moment of inertia [mass · (radius of gyration) ] of a rotor with respect to the shaft axis which the
machine can accelerate in a stated acceleration time shall be given for the range of balancing speeds (n , n , .)
1 2
together with the corresponding cycle rate (see table 2).
© ISO
Table 2 — Data of vertical machines
Manufacturer: . Model .
Balancing speeds or speed ranges (see also 4.2.3.1) n n n n n
1 2 3 4 5
Rotor mass kg maximum
(see note 1) minimum
Occasional overload force up to (see note 1) N
Maximum rotor moment of inertia with respect to the shaft axis
(see note 2) kg·m
Cycle rate (see note 2)
Maximum unbalance (see note 3)   g·mm/kg or g·mm measurable
permissible
Minimum achievable residual specific unbalance, e ,
mar
maximum mass
(see note 4 and clause 6) g·mm/kg
0,2 · max. mass
minimum mass
Corresponding deflection of analog amount-of-
unbalance indicator                         mm
maximum mass
Number of digital units (see note 4)
0,2 · max. mass
minimum mass
4.2.1.2  Production efficiency (see clause 7) shall be stated, as follows.
4.2.1.2.1  Time per measuring run:
a) Time for mechanical adjustment: . s
b) Time for setting indicating system: . s
c) Time for preparation of rotor: . s
d) Average acceleration time: . s
e) Reading time (including time to stabilize): . s
f) Average deceleration time: . s
g) Relating readings to rotor: . s
h) Other necessary time: . s
i) Total time per measuring run [a) to h) above]: . s
4.2.1.3  Unbalance reduction ratio: . %
4.2.2 Rotor dimensions
4.2.2.1  If the machine is equipped with two or more speeds, this information shall be stated for each speed. If the
machine is equipped with steplessly variable balancing speeds, then the information shall be given in the form of a
table, formula or graph.
© ISO
Adequate drawings of the support surface of the spindle or mounting plate, and of obstructions, such as drill heads,
electrical control cabinets, etc. above the mounting plate, shall be supplied to enable the user to determine the
maximum rotor envelope that can be accommodated and the tooling and/or adaptors required.
4.2.2.2  Maximum diameter: . mm
4.2.2.3  Rotor height:
a) Maximum overall height: . mm
b) Maximum height of centre of gravity: . mm
at 100 % of maximum mass: . mm
at 50 % of maximum mass: . mm
at 25 % of maximum mass: . mm
Rotor envelope limitations, including machine spindle or mounting plate interface (see figure 2) shall be
4.2.2.4
stated.
Key
1 Rotor 6 Centre of mass plane
2 Adapter 7 Lower correction plane
3 Protractor 8 Mounting holes for adapter
4 Spindle
9 Pilot Æ
5 Upper correction plane
Figure 2 — Example of vertical machine mounting interface illustrating rotor envelope limitations
© ISO
4.2.2.5  Correction plane limitations (consistent with the statements in 5.4) shall be stated.
4.2.3 Drive
4.2.3.1  Balancing speed Rated torque on workpiece
r/min N·m
n . .
n . .
n . .
n . .
n . .
n . .
n . .
n . .
4.2.3.2  Torque (see note 5):
a) Zero-speed torque: . % of rated torque on workpiece
b) Run-up torque adjustable from . to . % of rated torque on workpiece
c) Peak torque: . % of rated torque on workpiece
4.2.3.3  Prime mover (type of motor):
a) Rated power: . kW
b) Motor speed: . r/min
c) Power supply, voltage / frequency / phase: . / . / .
4.2.3.4  Brake
a) Type of brake:
b) Braking torque adjustable from . to . % of rated torque
c) Can brake be used as a holding device ? Yes / No
4.2.3.5  Motor and controls in accordance with the following standard(s): .
4.2.3.6  Speed regulation provided:
Accurate or constant within . % of . r/min, or . r/min
4.2.4 Couple unbalance interference ratio, g·mm / g·mm (see note 6)
4.2.5 Air pressure requirements: . Pa; . m /s
NOTE 1 The occasional overload force need only be stated for the lowest balancing speed. It is the maximum force that can
be accommodated by the machine without immediate damage.
NOTE 2 Cycle rate for a given balancing speed is the number of starts and stops which the machine can perform per hour
without damage to the machine when balancing a rotor of the maximum moment of inertia.
© ISO
NOTE 3 In general, for rigid rotors with two correction planes, one-half of the state value pertains to each plane; for disc-
shaped rotors, the full stated value holds for one plane.
NOTE 4 Limits for soft-bearing machines are generally stated in gram millimetres per kilogram (specific unbalance), since
this value represents a measure of rotor displacement and, therefore, motion of the balancing machine bearings. For hard-
bearing machines, the limits are generally stated in gram millimetres, since these machines are usually factory-calibrated to
indicate unbalance in such unit. (See also clause 6.) For two-plane-machines, this is the result obtained when the minimum
achievable residual unbalance is distributed between the two planes.
NOTE 5 In most cases, maximum torque is required for accelerating a workpiece. However, in the case of workpieces with
high windage and/or friction loss, maximum torque may be required at balancing speed.
NOTE 6 This value is only applicable for single-plane balancing machines. It describes the influence of couple unbalance in
the rotor on the indication of static unbalance.
5 Machine features
5.1 Principle of operation
An adequate description of the principle of operation of the balancing machine shall be given; for example, motion
measuring, force measuring, resonance, compensation.
5.2 Arrangement of the machine
5.2.1  The manufacturer shall describe the general configuration of this machine and the principal features of
design, for example:
 horizontal or vertical axis of rotation;
 soft- or hard-bearing suspension system;
 resonance-type machine with mechanical compensator.
5.2.2  The manufacturer shall provide details of the following, as applicable.
Components designed to support the rotor, for example:
5.2.2.1
 vee blocks;
 open rollers;
 plain half-bearings;
 closed-ball, roller or plain bearings;
 devices to accommodate rotors in their service bearings;
 devices to accommodate complete units.
NOTE Details of bearing lubrication requirements shall be given, where applicable.
5.2.2.2  The mechanical adjustment and functioning of the means provided to take up axial thrust from the rotor
(horizontal machines only).
Type(s) of transducers used to sense unbalance effects.
5.2.2.3
5.2.2.4  The drive and its control.
© ISO
5.3 Indicating system
5.3.1 General
A balancing machine shall have means to determine the amount of unbalance and its angular location; such means
shall be described, for example:
 wattmetric indicating system;
 voltmetric indicating system with phase-sensitive rectifier (including systems with frequency conversion);
 voltmetric system with stroboscope and filter;
 voltmetric indicating system with marking of angular position on the rotor itself;
 compensator with mechanical or electrical indication.
5.3.2 Amount indicators
The manufacturer shall describe the means of amount indication provided, for example:
 wattmetric or voltmetric component meters;
 wattmetric or voltmetric amount meters;
 wattmetric or voltmetric vector meters;
 mechanical or optical indicators;
 analog or digital readout.
5.3.3 Angle indicators
The manufacturer shall describe the means of angle indication provided, for example:
 wattmetric or voltmetric component meters;
 wattmetric or voltmetric vector meters;
 direct angle indication in degrees on a scale meter;
 oscilloscope, stroboscopic indicators;
 mechanical or optical indicators;
 analog or digital readout.
5.3.4 Operation of the indicating system
The manufacturer shall describe the procedure by which readings are obtained, taking into account at least the
following points.
a) How many measuring runs are required to obtain:
 the two readings for single-plane balancing?
 the four readings for two-plane balancing?
b) Is an indicator provided for each reading or is it necessary to switch over for each reading?
c) Are readings retained after the end of the measuring run?
d) Is an individual plus-and-minus switch provided for each plane which permits the indication of a heavy or light
spot?
© ISO
5.4 Plane separation system
This subclause is not applicable to single-plane machines; see.5.4.2.
5.4.1
The manufacturer shall state whether plane separation is provided. If it is provided, at least the following details
shall be given.
a) How is it operated for single rotors of a type not previously balanced?
b) How is it operated for single rotors in a series, with identical dimensions and mass?
c) The limits of workpiece geometry over which plane separation is effective shall be defined with the
effectiveness stated on the basis of the correction plane interference ratio, stating the following:
 the ratio of bearing distance to plane distance for which plane separation is effective;
 whether either or both correction planes can be between or outside the bearings;
 whether the centre of mass can be between or outside the two selected correction planes and/or bearings.
d) Whether the indicator system can also be used to measure directly static unbalance and couple unbalance.
5.4.2  On single-plane horizontal or vertical machines, the manufacturer shall state to what extent the machine is
able to suppress effects of couple unbalance (see 11.8).
5.5 Setting and calibration of indication
5.5.1 General
The manufacturer shall describe the means of setting and calibration and the means provided for checking these.
The manufacturer shall state whether setting is possible for indication in any desired unit, whether practical
correction units and/or standard weight or unbalance units.
The manufacturer shall state the number of runs required for calibrating the machine:
 for single-plane balancing;
 for two-plane balancing.
The manufacturer shall state the maximum permissible change, in percentage terms, in repeatability of speed
during calibration and operation.
5.5.2 Soft-bearing machines
The manufacturer shall state how calibration is accomplished on the first rotor of a particular mass and
configuration, for example, does the rotor have to be balanced by a trial-and-error procedure or is a compensator
provided, are calibration masses required, etc., and whether total or partial re-calibration is required when changing
the balancing speed.
If a compensator is provided, the limits of initial unbalance, of rotor geometry and speed for which compensation is
effective shall be stated.
5.5.3 Hard-bearing machines
The manufacturer shall state whether the machine is permanently calibrated and can be set according to the
workpiece or shall be calibrated by the user for different balancing speeds, rotor masses and/or dimensions.
© ISO
5.6 Other devices
Special devices which influence the efficient functioning of the balancing machine shall be described in detail, for
example:
 indication in components of an arbitrary coordinate system;
 indication of unbalance resolved into components located in limited sectors in more than two correction planes;
 correction devices;
 devices to correlate the measured angle and/or amount of unbalance with the rotor;
 suitable output for connection to a computer printer or other peripherals.
6 Minimum achievable residual unbalance
The minimum residual unbalance that can be achieved with a balancing machine shall be specified in terms of
specific unbalance in gram millimetres per kilogram (see definition in annex A) together with the corresponding
deflection of the amount-of-unbalance indicator.
This minimum achievable residual specific unbalance shall be stated for the full range of workpiece masses and
balancing speeds of the machine.
In achieving the stated residual unbalance, the manufacturer shall consider whether the accuracy of the following is
adequate for the purpose:
 amount indication,
 angle indication,
 plane separation,
 scale multiplier,
 drive, bearings, etc.
It should be noted that the stated minimum achievable residual unbalance value applies to the machine as
delivered, but if out-of-round journals, excessively heavy or loose adaptors or other tooling are employed by the
user, the minimum achievable residual unbalance may be affected.
7 Production efficiency
7.1 General
Production efficiency is the ability of the machine to assist the operator in balancing a rotor to a given residual
unbalance in the shortest possible time. It shall be assessed by using a proving rotor or, alternatively, a test rotor to
be specified by the user.
To find the production rate for a specific rotor (number of pieces per time unit or the reciprocal of the floor-to-floor
time), the time per measuring run, the necessary number of runs, the time for loading, unbalance correction and
unloading have to be taken into consideration. The necessary number of measuring runs depends on the average
initial unbalance, the tolerance and the unbalance reduction ratio (URR).
© ISO
7.2 Time per measuring run
For the proving rotor or rotors specified by the user, the manufacturer shall describe the procedure in detail and
state the average time for each of the operations listed under a) to h):
a) mechanical adjustment of the machine, including the drive, tooling and/or adaptor;
b) setting of the indicating system;
c) preparation of the rotor for the measuring run;
d) average acceleration time;
e) the reading time, i.e. the normal total time between the end of the acceleration run and the start of the
deceleration run;
f) average deceleration time;
g) any further operations necessary to relate the readings obtained to the actual rotor being balanced;
h) time for all other required operations, for example, safety measures.
NOTE 1 Items a) and b) are of primary interest for single rotor balancing.
NOTE 2 The time per measuring run is the total time required for steps a) to h) for the first run, but for subsequent measuring
runs on the same rotor, only steps d) to h) are required. In the case of mass production rotors, only steps c) to h) are required.
If special tools, not supplied as part of the standard equipment, are necessary to accommodate a rotor, this shall be
specified; for example, bearing inserts, couplings for drive shafts, shrouds, etc.
7.3 Unbalance reduction ratio
The manufacturer shall state the unbalance reduction ratio (see definition in annex A). It shall be assumed that the
addition or subtraction of mass is made without error and that normal skill and care are exercised in the operation of
the machine.
Where indicator systems that rely heavily on operator judgement are used, for example, stroboscopes, mechanical
indicators, etc., realistic values based on experience and related to the rotor to be balanced shall be given.
8 Performance qualifying factors
The manufacturer shall state the range of the following factors within which the machine is capable of achieving the
guaranteed performance, for example:
 temperature,
 humidity,
 balancing speed variation,
 line voltage and frequency fluctuations.
The manufacturer shall also state whether the performance of the machine is significantly changed by the use of
ball bearings on the rotor journals.
In addition, the manufacturer shall state whether the unbalance indication of the rotor is significantly affected if the
rotor bearing thrust face is not square to the axis.
© ISO
9 Installation requirements
9.1 General
In considering the siting of a balancing machine, the manufacturer shall state what precautions shall be observed to
obtain satisfactory performance in the presence of the following environmental factors:
 extraneous vibration,
 electromagnetic radiation,
 condensation, fungus and other factors, such as those referred to in clause 8.
9.2 Electrical and pneumatic requirements
Balancing machines shall be provided with standard input connections that are plainly marked with the required
supply voltage and frequency, air pressure, hydraulic pressure, etc.
9.3 Foundation
The manufacturer shall state the overall dimensions and mass of the machine, and the type and size of foundation
required for the machine under which its specified performance is assured; for example, concrete blocks,
workbench, etc.
10 Proving rotors and test masses
10.1 General
This clause specifies technical requirements for a range of proving rotors for use in testing balancing machines. It
specifies rotor masses, materials. dimensions, limits, tapped hole dimensions, rotor balancing requirements and
details of test masses. The extent and costs of tests and the rotor size(s) may be negotiated between the
manufacturer and the user.
10.2 Proving rotors
10.2.1  Three types of proving rotors are defined, named A, B and C (Figure 3). Typical workpieces, which are
intended to be represented by the proving rotors, are characterized as follows.
1)
 Type A: Rotors without journals, balanced on a vertical machine , in one or two correction planes.
Service bearing planes may be anywhere; i.e. one on each side, or both on one side of the main
rotor body. For the tests it is assumed that one bearing is on each side of the rotor.
 Type B: Inboard rotors with journals, balanced on a horizontal machine, mostly with two correction planes
between the bearings.
Service bearings are positioned on either side of the rotor.
 Type C: Outboard rotors with journals, balanced on a horizontal machine, with two overhung correction
planes.
Service bearing positions are similar to those on the proving rotor.
NOTE 1 Type C proving rotor is composed of a shaft and a proving rotor type A.
NOTE 2 Calculations for U for type C proving rotor are based on the total mass (shaft and proving rotor type A).
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1)
They may be balanced on a horizontal machine with integrated spindle.
© ISO
a)  Vertical balancing machine
b)  Horizontal balancing machines
NOTE 1 Mass centre position is inboard in Types A and B but outboard in Type C (shaft plus type A rotor).
Figure 3 — Proving rotors type A, B, C with test planes 1, 2, 3 and assumed bearing planes I, II
Each type of proving rotor has three planes for attachment of test masses.
The same proving rotor and test masses will be used for tests in one or two planes.
10.2.2  The manufacturer shall state whether or not a proving rotor is supplied with the machine.
10.2.3  Proving rotors shall be manufactured of steel and shall be similar to those shown in figure 4 and table 3 for
vertical machines, figure 5 and table 4 for horizontal machines (inboard rotor), and figure 6 and table 5 for outboard
rotors (see 10.2.5).
10.2.4  For machines covered by this International Standard, the manufacturer shall have available proving rotors
that may be used to confirm the performance of each machine prior to shipment from the plant.
10.2.5  If a horizontal machine is to be used for balancing outboard rotors (or inboard rotors with correction planes
overhanging on one side), additional tests have to be agreed upon (see 11.1). These require a proving rotor type C.
NOTE 1 Older style rotors with only eight holes per plane may be modified to this International Standard (see annex E).
NOTE 2 The shipment of proving rotors to the user is the subject of individual negotiation.
10.2.6  Clear and permanent angle markings shall be provided on every proving rotor every 10° and enumerated at
intervals of 30°. Two such scales with a clockwise and anticlockwise enumeration may be provided.
For testing stroboscopic machines, the proving rotor shall be equipped with a numbered standard band
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