ISO INTERNATIONAL STANDARD 21250-4 First edition 2020-07 Rolling bearings Noise testing of rolling bearing greases - Part 4: Test and evaluation method NQ Roulements -Essais de bruit de graisse pour roulement- Partie4:Meéthoded'essaiet interpretationNQ Reference number IS021250-4:2020(E) ISO @IS02020 IS021250-4:2020(E) COPYRIGHTPROTECTEDDOCUMENT IS02020 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 below or Iso's member body in the country of the requester. ISo copyright office CP 40i: Ch.de Blandonnet 8 CH-1214 Vernier,Geneva Phone: +4122749 0111 Email: copyright@iso.org Website: www.iso.org Published in Switzerland i @ IS0 2020 - All rights reserved IS021250-4:2020(E) Contents Page Foreword iv Introduction. .V 1 Scope. 1 2 Normative references 1 3 Terms and definitions 1 4 Symbols, abbreviated terms and subscripts .2 5 Calculation method .2 5.1 Signal processing 2 5.2 Peak detection. 2 6 Test method NQ .4 6.1 Measuring principle .4 6.2 Testing procedure. .4 7 Evaluation of results .5 Annex A (informative) Test machine 6 AnnexB(informative)Calibration .9 Bibliography 10 @IS0 2020 - All rights reserved iii