XITRON XT2640 - Compliance Tests Performed by the XT2640 During Assessment

XT2640OperatingManual 13July2016 Page92of187
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Phaseshiftandfrequencyresponse.Ifthedevicehasapoorphaseshiftspecificationat50/60Hzthenitusuallyhasapoor
frequencyresponseat2kHz.Thedifferencebetweentheinput:outputratioat2kHztothatat50/60Hzshouldbe<1%.
18.1.6 COMPLIANCETESTSPERFORMEDBY THEXT2640DURINGASSESSMENT
ThefollowingtestsareperformedbytheXT2640toensurethatEUTassessmentisperformedinamannercompliantwiththe
standards.
18.1.6.1 TESTINGTHESUPPLYVOLTAGEFORCOMPLIANCE
WiththeXT2640,youmayuseanyvoltagesourcehavingsuitablepowersourcingcapabilities.Howeveritshouldbenotedthatthe
localmainssupplyisoftennotsuitable,particularlyforEN61000‐3‐2assessments.
InaccordancewiththerequirementsofEN61000‐3‐2and‐12thesupplyvoltageiscontinuouslycheckedbytheXT2640throughout
theassessmentoftheEUTasfollows.NotethatalthoughsometestsarenotrequiredforsomeEUTclassifications,theXT2640
alwaysperformsallofthetests,theEUTclassificationonlyaffectswhethertheresultsofthesetestsarevisibletoyou.
Voltage:Eachvoltageischeckedthatitremainscontinuouslywithina±2%rangeoftheuserspecifiednominalvoltage
(Unom)asspecifiedbyEN61000‐3‐2clauseA.2aand‐12clause7.2b.
Frequency:Thesupplyfrequencyischeckedthatitremainscontinuouslywithina±0.5%rangeoftheuserspecified
nominalfrequency(Fnom)asspecifiedbyEN61000‐3‐2clauseA.2aand‐12clause7.2b.
FrequencyLock:Short‐termvariationsinthesupplyfrequencyarecontinuouslycheckedthattheyremainwithinthe
±0.03%limitwithinevery200msmeasurementperiodasspecifiedbyEN61000‐4‐7clause4.4.1soisapplicabletoboth
EN61000‐3‐2and‐12assessments.
Inmostcountriesthelocalmainssupplydoesnotmeetthisrequirement.InadditionsomeACsourcesmayhave
cycle‐to‐cyclejitterinexcessofthisrequirement.
VoltageHarmonics:EachvoltageischeckedthatitremainscontinuouslywithinthespecificationsofEN61000‐3‐2clause
A.2c.ForEN61000‐3‐12itisyourresponsibilitytocheckthevoltageharmonicsofeachsupplyphasevoltagewhenthe
supplyisunloadedperclause7.2d.
ForEN61000‐3‐12thiscanbeperformedusingtheXT2640HARMONICSscreenbutitisnotpartofthe
assessmentprocess.
VoltageCrestFactor:Eachvoltageischeckedthatitscrestfactorremainscontinuouslywithinamodificationoftherange
specifiedbyEN61000‐3‐2clauseA.2d,seebelowforadescriptionofthemodificationtoEN61000‐3‐2requirementsused
bytheXT2640inthisregard.EN61000‐3‐12containsnosuchrequirementandcrestfactorisnotcheckedwhenassessing
aEUTtothatstandard.
Thecrestfactorofapure,noiseless,sinewaveis1.414214(=√2to7significantfigures)andiftheEN61000‐3‐2
statedallowablerangeof1.40to1.42istakenstrictly(assumingthatallunstateddigitsarezeroes)thenthis
statedrangeonlyallows0.4%forthetotalnoise(alwaysincreasesCF)+amplitudemodulation(alwaysincreases
CF)+anydistortioncontentwhichresultsinanincreaseinthecrestfactor,thismaybeoverlyrestrictivein
practice.IntheXT2640itisassumedthattheintentionofthestandardistodefinea±0.01rangecenteredonthe
nominalvalueforapuresinewave(insteadofthe1.41valueasstated)sotheactualallowedrangeforsupply
voltagecrestfactorascheckedbytheXT2640isfrom1.404214to1.424214(to7significantfigures).Itshouldbe
notedthatEN61000‐4‐7clause5.4.2.2d,althoughoverriddeninthisregardbyEN61000‐3‐2,statesarequired
rangeof1.404to1.424.
Thereisnodefinitionofanybandwidthrequiredforthismeasurementineitherofthesestandards,forexamplea
100GHzmeasurementbandwidthwouldcertainlynotresultinasuitableapplicationofthislimit.Soitis
assumedthata“reasonable”limitshouldbeusedandtheXT2640usesa20kHzbandwidthlimitforthis
measurement.
PhaseofVoltagePeaks:Eachvoltageiscontinuouslycheckedthatthephasepositionofbothpositiveandnegativepeaks
are±90°±3°asspecifiedbyEN61000‐3‐2clauseA.2d.EN61000‐3‐12containsnosimilarrequirementandthepeakphase
positionisnotcheckedwhenassessingaEUTtothatstandard.
Thereisnodefinitionofanybandwidthrequiredforthismeasurement,forexamplea100GHzmeasurement
bandwidthwhichcoulddetectanoisepulseasshortas5nswouldcertainlynotresultinasuitableapplicationof
thislimitasthe3°rangeonlyallowsforasmallamountofvoltagenoise,particularlysinceeverysupplycycle
withintheassessmentperiodmustmeetthislimitsoevenaverylowprobabilitynoiseeventwillcauseafailure
ofthisrequirement.Soitisassumedthata“reasonable”bandwidthlimitshouldbeusedandtheXT2640usesa
5kHzbandwidthlimitforthismeasurement,butitshouldbenotedthatalmostanysuchbandwidthrestriction
resultsinadelaywhichvarieswiththefrequencycontentandexactshapeofthenoisepulse,asisthecaseforthe
XT2640,andthisdelaymayresultinthe3°rangerequirementhavinglimitedmeaninginpractice.
Inter‐phaseVoltagePhasing:Thephasedifferencebetweeneveryphasepairofamulti‐phasesupplyisrequiredtobe
within±1.5°of120°throughouttheassessmentperiodaccordingtotherequirementsofbothEN61000‐3‐2clauseA.2b
and‐12clause7.2c.TheXT2640continuouslychecksthisthroughouttheassessmentifWIRINGisconfiguredfor
3ø3w(3ch)or3ø4w.
Recommendations:
TheXT2640neitherstopstheassessment,norpreventsanoverallassessmentpass/failresultoftheEUTharmonics
emissionsifanyofthesesupplyvoltagetestsfail.Aseparateindicationisuseddenotingwhich(ifany)ofthesetestsfail.
Shouldanyofthesefailuresbedetected(particularlyVoltageCrestFactorandPhaseofVoltagePeaks)thenyouare
recommendedtoreachadecisionwhetherto‐
a)
Ignorethefailure.ThisisapossibilityiftheEUTresultsindicatethatitmeetstheharmonicsrequirementswitha
highmargin,particularlysinceinpracticethepresenceofsuchsupplyfailureswouldnormallyresultinhigher