Samlexpower PST-100S-12E Owner's Manual - Section 2 |
8 | SAMLEX AMERICA INC.
theinverter.TheinvertercanbesizedbasedontheActivePowerrating(Watts)without
creating overload.
Reactive Load:Adeviceorappliancethatconsistsofacombinationofresistive,induc-
tiveandcapacitiveelements(likemotordriventools,refrigerationcompressors,micro-
waves,computers,audio/videoetc.).ThesedevicesrequireApparentPower(VA)from
theinvertertooperate.TheApparentPowerisavectorialsumofActivePower(Watts)
andReactivePower(VAR).The inverter has to be sized based on the higher Apparent
Power (VA).
output Voltage Waveforms
Fig. 2.1: Pure and Modified Sine Waveforms
TheoutputwaveformoftheSamlexPSTSeriesinvertersisapuresinewavelikethe
waveform of the grid power. Please see sine wave represented in the fig. 2.1 that also
shows modified waveform for comparison.
Inasinewave,thevoltagerisesandfallssmoothlywithasmoothlychangingphase
angle and also changes its polarity instantly when it crosses 0 Volts. In a modified sine
wave,thevoltagerisesandfallsabruptly,thephaseanglealsochangesabruptlyand
itsitsat0Vsforsometimebeforechangingitspolarity.Thus,anydevicethatusesa
controlcircuitrythatsensesthephase(forvoltage/speedcontrol)orinstantaneouszero
voltagecrossing(fortimingcontrol)willnotworkproperlyfromavoltagethathasa
modified sine waveform.
Also,asthemodifiedsinewaveisaformofsquarewave,itiscomprisedofmultiple
sinewavesofoddharmonics(multiples)ofthefundamentalfrequencyofthemodified
sinewave.forexample,a50Hzmodifiedsinewavewillconsistofsinewaveswithodd
harmonicfrequenciesof3rd(150Hz),5th(250Hz),7th(350Hz)andsoon.Thehigh
seCtIOn 2 |
General Information
TIME
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0
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Modified Sine
Wave sits at
ZERO for some
time and then
rises or falls
Modified Sine Wave
Sine Wave
Pure Sine Wave
crosses 0.0V
instantaneously