ISO 21940-21:2022

Mechanical vibration — Rotor balancing — Part 21: Description and evaluation of balancing machines

This document sets out the requirements for evaluating hard and soft bearing balancing machines that support and rotate: a) rotors with rigid behaviour at balancing speed (as described in ISO21940-11); b) rotors with shaft elastic behaviour and balanced in accordance with low speed balancing procedures (as described in ISO21940-12).

Vibrations mécaniques — Équilibrage des rotors — Partie 21: Description et évaluation des machines à équilibrer

General Information

• Status: Published
• Publication Date: 06-Nov-2022
• 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: 6060 - International Standard published
• Start Date: 07-Nov-2022
• Due Date: 22-Mar-2022
• Completion Date: 07-Nov-2022

Relations

• Revises: ISO 21940-21:2012 - Mechanical vibration — Rotor balancing — Part 21: Description and evaluation of balancing machines
• Effective Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21940-21
Second edition
2022-11
Mechanical vibration — Rotor
balancing —
Part 21:
Description and evaluation of
balancing machines
Vibrations mécaniques — Équilibrage des rotors —
Partie 21: Description et évaluation des machines à équilibrer
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword . vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Capacity and performance data of the balancing machine . 1
4.1 General . 1
4.2 Data for horizontal balancing machines . 1
4.2.1 Rotor mass and unbalance limitations . 1
4.2.2 Production efficiency . 2
4.2.3 Rotor dimensions . 3
4.2.4 Balancing machine drive data . 4
4.2.5 Torque . 4
4.2.6 Type of rotor drive . 5
4.2.7 Brake . 5
4.2.8 Motor and controls . 5
4.2.9 Speed regulation . . 5
4.2.10 Couple moment interference ratio, I . 5
sc
4.2.11 Air pressure requirements . 5
4.3 Data for vertical balancing machines . 5
4.3.1 Rotor mass and unbalance limitations . 5
4.3.2 Production efficiency . 6
4.3.3 Rotor dimensions . 6
4.3.4 Balancing machine drive data . 8
4.3.5 Torque . 8
4.3.6 Type of drive to rotor . 8
4.3.7 Brake . 8
4.3.8 Motor and controls . 8
4.3.9 Speed regulation . 8
4.3.10 Couple moment interference ratio . 8
4.3.11 Air pressure requirements . 8
5 Machine features . 8
5.1 Principle of operation . 8
5.2 Machine arrangement . 8
5.3 Measuring system . 9
5.3.1 General . 9
5.3.2 Unbalance indicators . 9
5.3.3 Additional features . 9
5.3.4 Operation of the indicating system . . 10
5.4 Plane separation system . 10
5.4.1 Multi-plane balancing machines. 10
5.4.2 Single-plane horizontal or vertical balancing machines . 10
5.5 Setting and calibration of the measuring system . 10
5.5.1 General . 10
5.5.2 Soft-bearing machines . 11
5.5.3 Hard-bearing machines . 11
6 Production efficiency .11
6.1 General . 11
6.2 Time per balance cycle .12
6.3 Unbalance reduction ratio, R . 13
UR
7 Performance qualifying factors . .14
iii
8 Installation requirements .14
8.1 General . 14
8.2 Supply requirements . 14
8.3 Foundation . 15
9 Proving rotors and test masses . .15
9.1 General . 15
9.2 Standardized proving rotors . 15
9.3 User defined proving rotors . 17
9.4 Test masses . 17
9.4.1 General . 17
9.4.2 U test masses . 24
mar
9.4.3 R test masses . 25
UR
9.4.4 Permissible test mass errors . 26
9.4.5 Material. 27
10 Balance machine verification tests .27
10.1 General . 27
10.2 Requirements for evaluating balance machine performance .28
10.3 Test speed .29
10.4 Test for establishing the minimum achievable residual unbalance, U .29
mar
10.4.1 General .29
10.4.2 Initial balancing machine setting .29
10.4.3 Unbalance added . 31
10.4.4 Readings .
...