IS/ISO 21940-21 : 2022 Mechanical Vibration - Rotor Balancing - Part 21 Description and Evaluation of Balancing Machines

ICS 21.120.40

MED 28

NATIONAL FOREWORD

This Indian Standard (Part 21) (First Revision) which is identical to ISO 21940-21 : 2022 'Mechanical vibration - Rotor balancing - Part 21: Description and evaluation of balancing machines' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on recommendation of the Mechanical Vibration and Shock Condition Monitoring Sectional Committee and approval of the Mechanical Engineering Division Council.

This standard was first published in 2017 as IS/ISO 21940-21 : 2012 'Mechanical vibration - Rotor balancing: Part 21 Description and evaluation of balancing machines'. This revision has been undertaken to align it with the latest version of ISO 21940-21 : 2022.

The main changes are as follows:

a) The introduction of new computer based technology into balance machine indication systems;

b) The introduction of additional tests for repeatability and speed range (see Annex F and Annex G); and

c) The introduction of greater clarification for use with automated and special purpose machines.

Under the general title 'Mechanical vibration - Rotor balancing', the standard is in ten parts, other parts are as following:

Part 1 Introduction

Part 2 Vocabulary

Part 11 Procedures and tolerances for rotors with the rigid behavior

Part 12 Procedures and tolerances for rotors with flexible behavior

Part 13 Criteria and safeguards for the in-situ balancing of medium and large rotors

Part 14 Procedures for assessing balance errors

Part 23 Enclosures and other protective measures for balancing machines

Part 31 Susceptibility and sensitivity of machines to unbalance

Part 32 Shaft and fitment key convection

The text of ISO standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standard. Attention is particularly drawn to the following:

a) Wherever the words 'International Standard' appear, referring to this standard, they should be read as 'Indian Standard'; and

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.