ICS 87.040                          MED 28

(Superseding IS 14280 : 1995)

Reaffirmed 2019

NATIONAL FOREWORD

This Indian Standard (Part 32) which is identical with ISO 21940-32 : 2012 ‘Mechanical vibration - Rotor balancing - Part 32: Shaft and fitment key convention’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Mechanical Vibration and Shock Sectional Committee and approval of the Mechanical Engineering Division Council.

This standard supersedes IS 14280 : 1995 ‘Mechanical vibration - Balancing - Shaft and fitment key convention’. After publication of this standard, shall be treated as withdrawn.

It is often impossible or economically unreasonable to balance rotors with fitments after they have been assembled: the rotor components which also may originate from different suppliers are therefore balanced separately. An appropriate balance tolerance is applied to each component so that, when shaft and fitment(s) are coupled together, the rotor assembly meets the require balance tolerance and/or vibration limit. For coupling the fitment(s) to the shaft, different methods are applied, a very common one uses keys. If, however, a different key convection has been used when balancing the shaft then that one used for balancing the fitment(s), it is quite likely that the rotor assembly has a balance error influencing its residual unbalance.

There are three methods, or key convections, for balancing shaft and fitments coupled together with keys:

- full-key convection

- half-key convection

- no-key convection

Under the general title ‘Mechanical vibration - Rotor balancing’, the standard is in ten parts, other parts areas 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 21 Description and evaluation of balancing machines

Part 23 Enclosures and other protective measures for balancing machines

Part 31 Susceptibility and sensitivity of machines to unbalance

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are however not identical to those used in Indian Standards. 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’.

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.