1、Designation:B53902(Reapproved 2013)Standard Test Methods forMeasuring Resistance of Electrical Connections(StaticContacts)1This standard is issued under the fixed designation B539;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the y
2、ear 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 These test methods cover equipment and techniques formeasuring the resistance of static electrical connections such
3、aswire terminations or splices,friction connectors,solderedjoints,and wrapped-wire connections.1.2 Measurements under two distinct levels of electricalloading are described.These levels are:(1)dry circuit,(2)andrated current.One or both of these levels of loading may berequired in specific cases.1.3
4、 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 appropriateMaterial Safety Data Sheet(MSDS)for this product/materialas provide
5、d by the manufacturer,to establish appropriatesafety and health practices,and determine the applicability ofregulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B542 Terminology Relating to Electrical Contacts and TheirUseE122 Practice for Calculating Sample Size to Estimate
6、,WithSpecified Precision,the Average for a Characteristic of aLot or Process3.Terminology3.1 Definitions:3.1.1 See Terminology B542 for definitions of contactresistance,film resistance,and constriction resistance.3.1.2 bulk resistance,nthe resistance a contact assemblywould have if it were solid met
7、al of an identical geometry sothat the nominal contact area offered zero resistance.Whenmeasuring contact resistance one attempts to include as littlebulk resistance as possible in the measurement,by placingmeasuring probes as close to the contact interface as practical.3.1.3 connection resistance,n
8、the resistance from the ter-mination point on one end of a device containing staticcontacts,through the contacts to the termination point on theother end of the device.The termination point is the location ona terminal of a device where a wire or printed circuit pathelectrically connects to the term
9、inal.This resistance is thevalue of resistance displayed by the device in a circuitapplication.3.1.3.1 DiscussionThe term contact resistance is oftenused in commercial literature to indicate the connection resis-tance displayed by the device in a standard application.In themore rigorous usage of con
10、tact resistance,the connectionresistance is the sum of the contact resistance plus the bulkresistance of leads within the device that go to the staticcontacts from the point that the leads are connected to theexternal circuitry.Measurement of contact resistance indepen-dent of all bulk resistance is
11、 very difficult for most commercialdevices.3.1.4 dry circuit,na circuit in which the open-circuitvoltage is less than or equal to 20 mV.Current is usually lowin a dry circuit,but a low-current circuit is not necessarily adry circuit.When the applied voltage(open-circuit voltage)istoo low to cause an
12、y physical changes in the contact junction,such as break-down of thin insulating films or softening ofcontact asperities,the circuit is said to be a dry circuit.3.1.5 open-circuit voltage,nthe steady-state voltagewhich would appear across the contacts if they were opened.3.1.6 static contacts,nelect
13、ric junctions designed forinfrequent separation and connection,and intended to performtheir function only when contacting members are stationaryrelative to each other.This definition includes crimped,welded,brazed,riveted,or soldered joints;friction connectionssuch as pin and socket connectors or ta
14、per pins,twisted-wiresplices;and connections made with screws,or bolts and nutsbetween electrical wiring and components.The definitionexcludes relay contacts,slip rings and commutators,andswitches and circuit breakers.1These test methods are under the jurisdiction of ASTM Committee B02 onNonferrous
15、Metals and Alloys and are the direct responsibility of SubcommitteeB02.11 on Electrical Contact Test Methods.Current edition approved Aug.1,2013.Published August 2013.Originallyapproved in 1970.Last previous edition approved in 2008 as B539 02(2008).DOI:10.1520/B0539-02R13.2For referenced ASTM stand
16、ards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2 Descriptions of Terms for Levels of Electrical Loading:3.2.1 dry circuit,nThis method provides for measurementof contact resistance under very low levels of electricalexcitation,
