ASTM_B_615_-_79_2017.pdf

Designation:B61579(Reapproved 2017)Standard Practice forMeasuring Electrical Contact Noise in Sliding ElectricalContacts1This standard is issued under the fixed designation B615;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes the practices and factors consid-ered to be most important in the measurement of electricalcontact noise of sliding contacts.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateSafety Data Sheet(SDS)for this product/material as providedby the manufacturer,to establish appropriate safety and healthpractices,and determine the applicability of regulatory limi-tations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Terminology2.1 Definitions:2.1.1 contact noise,nthe varying voltage across a pair ofelectric contacts due to conditions at their interface.It is to bedistinguished from the variation of signal due to its transmis-sion through electrical conductors(that is,induced voltagesdue to adjacent sources).It is also to be distinguished fromacoustic noise which may be generated by the contact action.2.1.1.1 DiscussionStepwise change of resistance of awirewound potentiometer due to the definite resistance of asingle turn is not electrical contact noise.2.1.2 switching or edge noise,nthe electrical contactnoise occurring during the period of transition from conductionto non-conduction(or vice versa)of a switching device.3.Significance and Use3.1 Resistance or voltage values alone do not providesufficient detail for an engineering evaluation of contact noise.This practice lists the test conditions that should be reportedwith noise measurements and indicates some conditions(opencircuit voltages,currents,etc.)that have been used for qualitycontrol and research studies.The use of these practices shouldprovide sufficient detail for an engineering interpretation of thenoise data and allow the tests to be repeated by anotherlaboratory.4.Types of Testing4.1 Type IQualification and acceptance testing of electro-mechanical devices when low electrical contact noise isimportant for proper functioning.4.1.1 Electrical and mechanical parameters should closelysimulate the end use of the device.4.1.2 Since the procedure is used as a method of qualitycontrol,the test parameters must be duplicated each time thetest is conducted.4.2 Type IIMeasurement of contact voltage variation as amethod of studying tribological phenomena.4.2.1 Tests are designed with specific diagnostic or researchgoals.4.2.2 Electrical and mechanical parameters are based onconsiderations of basic contact physics and not the engineeringrequirements of the device.Selected parameters may be variedas part of the test.For example,rotational rate of a slip ringmay be varied to determine the surface velocity at whichhydrodynamic lift becomes important.5.Test Conditions5.1 The following test conditions should be controlled orknown to enable adequate evaluation of test results:5.1.1 Electrical Parameters:5.1.1.1 CurrentContact current and waveform should bespecified.The limitations of the instrument(s)being used tomeasure the noise and adequacy of shielding from extraneousnoise sources must be considered when current level is chosen.Type I tests may be made either at current levels chosen tosimulate those required in actual use or may be at highercurrent levels in order to enhance test sensitivity provided any1This practice is under the jurisdiction of ASTM Committee B02 on NonferrousMetals and Alloys and is the direct responsibility of Subcommittee B02.11 onElectrical Contact Test Methods.Current edition approved April 1,2017.Published April 2017.Originallyapproved in 1979.Last previous edition approved in 2011 as B615 79(2011).DOI:10.1520/B0615-79R17.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 such higher current magnitude shall be agreed upon betweenthe device user and producer(Note 1).5.1.1.2 Source VoltageThe maximum open-circuit vol