ASTM_F_1662_-_10.pdf

Designation:F166210Standard Test Method forVerifying the Specified Dielectric Withstand Voltage andDetermining the Dielectric Breakdown Voltage of aMembrane Switch1This standard is issued under the fixed designation F1662;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 test method covers the verification of a specifieddielectric withstand voltage or dielectric breakdown voltage ofa membrane switch.2.Referenced Documents2.1 ASTM Standards:2F1680 Test Method for Determining Circuit Resistance of aMembrane SwitchF1663 Test Method for Determining the Capacitance of aMembrane Switch3.Terminology3.1 Definitions:3.1.1 dielectric withstand voltagea voltage,above ratedvoltage,applied for a specific time between mutually insulatedtest points or between an insulated test point and ground,whichresults in no visual change or specified leakage current.3.1.2 dielectric breakdown voltagethe voltage at which adisruptive discharge or excessive leakage current occurs.3.1.3 disruptive dischargeflashover(surface discharge),spark over(air discharge),or breakdown(puncture discharge).3.1.4 leakage currentcurrent between mutually insulatedtest points when a voltage is applied.3.1.5 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.3.1.6 test pointstwo preselected mutually insulated loca-tions on switch assembly.4.Significance and Use4.1 Dielectric withstand voltage testing is useful for designverification,quality control of materials,and workmanship.4.2 This test method is used to verify that the membraneswitch can operate safely at its rated voltage,and withstandmomentary overpotentials due to switching,surges and othersimilar electrical phenomena.4.3 Specific areas of testing are,but not limited to:4.3.1 Conductor/dielectric/conductor crossing point,4.3.2 Close proximity of conductors,and4.3.3 Any other conductive surface such as shielding ormetal backing panel.4.4 Dielectric withstand voltage testing may be destructiveand units that have been tested should be considered unreliablefor future use.4.5 Testing using ac voltage may be useful for switchesintended for control circuits powered by ac voltages.5.Interferences5.1 The following parameters may affect the results of thistest:5.1.1 Humidity,5.1.2 Contamination,and5.1.3 Temperature.6.Apparatus6.1 Electric Device,suitable to provide a controlled dc or acvoltage,leakage current measurement.7.Procedure7.1 Dielectric Withstand Test Method:7.1.1 Measure and record the following characteristics priorto performing test:7.1.1.1 Open and closed circuit resistance of the test pointsin accordance with Test Method F1680.7.1.1.2 Capacitance of the test point in accordance withF1663.7.1.2 Connect two test points on the switch assembly,eachto a separate polarity,on the voltage source.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved May 1,2010.Published June 2010.Originallyapproved in 1995.Last previous edition approved in 2004 as F1662-04.DOI:10.1520/F1662-10.2For referenced ASTM standards,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 7.1.3 Select test voltage from Table 1.7.1.4 Apply the test voltage from zero to specified value asuniformly as possible,at a rate of approximately12of the testvoltage per second(V/s),unless otherwise specified.Forexample,Level 2 in Table 1,the ramp rate is 250 V/s for a testvoltage of 500 V dc.7.1.5 Apply test voltage to switch assembly for 60 s.7.1.6 Record visual changes or leakage current,or both,ifany.7.1.7 Dissipate all charges to ground using appropriatemethods prior to continuing test to next test voltage(repeat7.1.3 to 7.1.7 as needed).7.1.8 Repeat measurements recorded in 7.1.1.7.2 Dielectric Breakdown Method:7.2.1 Connect two test points on the switch assembly,eachto a separate polarity,on the voltage source.7.2.2 Apply the voltage incrementally from zero to break-down as uniformly as possible,at a rate of 250 V/s unlessotherwise specified.7.2.2.1 Apply test voltage to switch assembly for 60 s ateach incremental test voltage.7.2.3 Record visual changes and magnitude of breakdownvoltage,if any.7.2.4 Dissipate all charges to ground using appropriatemethods prior to continuing test to additional test points(repeat7.2.1 to 7.2.4).8.Report8.1 Report the following information:8.1.1 Temperature,8.1.2 Relative humidity,8.1.3 Specified dielectric withsta