XITRON XT2640 - Non-Harmonic Phase Results; Harmonic Phase Results; Relative Individual Harmonics Results; Percentage Distortion Results

XT2640OperatingManual 13July2016 Page31of187
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Inthisdrawingthesignal‘2’maybereferredtoashavinga120°phaserelationshiptosignal‘1’andsignal‘3’ashavinga
240°relationshiptosignal‘1’,whereasmathematicallytheyaresin(ωt+240°)(=sin(ωt‐120°))andsin(ωt+120°)
(=sin(ωt‐240°))respectively.IntheXT2640thisisdescribedasa“Delay”basedphaseratherthanthe“Math”based
phase.
TheXT2640supportsseveralmethodsofshowingphaseresultsasselectedbyapreferencesetting(see12.3.1.6)whichaffectsALL
phaseresults.Thereare3partstothispreferencesetting,asfollows‐
 NumericRange.Youcanselectthatphaseresultsareshownwitha‐180to+180°rangeora0to360°range.Notethat
thesearemathematicallyequivalent,e.g.sin(ωt‐120°)isthesameassin(ωt+240°).
 MathorDelayBasis.Youcanselectwhetheramathematicalbasisoradelaybasisisusedforphaseresultsasdescribed
above.Thisaffectsthemathematicaluseofresultsanditaffectsallphaseresults,e.g.sin(ωt‐120°)isNOTthesameas
sin(ωt+120°)soiftheDelaypreferenceforphaseisselectedthenyoumustincludethepolarityreversalinany
mathematicswhichyoumightperformontheresults.
o UsingaMathsetting‐ifaphaseoføisshownthenmathematicallythesignalisS.sin(ωt+ø).
o UsingaDelaysetting‐ifaphaseoføisshownthenmathematicallythesignalisS.sin(ωt–ø).
 CWorCCWvectors.YoucanselectwhethertheVECTORSpolarchart(see12.8)isshowninaclockwise(CW)orcounter‐
clockwise(CCW)directionforpositivelyincreasingphaseafterincorporatingthebasisabove.Note,onlythewayinwhich
phaseisgraphicallyshownisalteredbythis.
11.7.1 NON‐HARMONICPHASERESULTS
Non‐harmonicphaseforachannelorforaVPAistheinversecosineoftherespectivePFusingthelead/lagdeterminationto
determinethepolarityoftheresult.Insomeindustrysegmentsthisisnamedeffectiveorapparentphase.
11.7.2 HARMONICPHASERESULTS
FundamentalVoltage PhaseisrelativetotheVfundamentalinthelowestnumberedchanneloftheVPA
Non‐fundamentalVoltage PhaseisrelativetotheVfundamentalintheselectedchannel
FundamentalCurrent PhaseisrelativetotheVfundamentalintheselectedchannel
Non‐fundamentalCurrent PhaseisrelativetotheAfundamentalintheselectedchannel
11.8 RELATIVEINDIVIDUALHARMONICSRESULTS
Individualharmonicsgivenasapercentagearethepercentagerelativetothefundamentalofthatsignalunlessotherwisestated.
11.9 PERCENTAGEDISTORTIONRESULTS
PercentageharmonicdistortionisgivenrelativetofundamentaldenotedasTHDf,orrelativetototalAC+DCsignaldenotedas
THDsig,orrelativetotheACsignaldenotedasTHDac.
11.10 THC,POHCANDPWHCRESULTS
ThesearetheRMScurrentamplitudemeasurementswhichwouldresultifonlycertainharmonicswereincludedthecurrentsignal.
THC Includesallharmonicsexceptthefundamental
POHC Includesalloddharmonicsatandabovethe21
st

PWHC Includesallharmonicsabovethe14
th
,witheachharmonicamplitudeweightedbymultiplyingbythe
squarerootofits’harmonicnumber
Thesearenotrelativemeasurements;theresultsareintheunitsofAmps.
11.11 MECHANICAL(MOTOR)RESULTS
MotorSpeedisprovided(ifconfigured)intheunitsofrpm(revolutionsperminute).
IfMotorSpeedisnotconfiguredtobemeasured,butinsteadisconfiguredtobederivedfromthedrivefrequencythenitis
computedasMotorSpeed=60*DriveFrequency/Numberofpoles
MotorTorqueisprovided(ifconfigured)intheunitsofNm(Newton.Metres).
MechanicalPoweriscomputedasMotorPower=MotorSpeed*MotorTorque*(2*π/60)andisintheunitsofWatts.
MotorSlipiscomputedasPercentageSlip=100*(DriveFrequency–(MotorSpeed*Numberofpoles/60))/DriveFrequency
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