TechnicalInstructions LMVSeries
DocumentNo.LV5‐1000
Section5 Page8 SCCInc.
2. Thestaticoutputpressureoftheblower(SP)variesbythesquareofthechangeinRPM:
3. Therequiredbrakehorsepoweroftheblower(BHP)variesbythecubeofthechangeinRPM:
Example:Ablowerspinningat1750RPMproduces10inWCofstaticpressure,4500CFMofflow,and
requires20BH
P.WhathappensiftheRPMisincrea
sedto2750RPM?
Assumptions:Airdamperiswideopen,andsystemeffects(suchastherestrictionduetotheboiler's
heatexchanger,theburner’s diffuser,etc...)arenottakenintoaccount.
Flow: CFM(new
)=(2750/1750)*4500=7071CFM
Pressure: SP(new)=(2750/1750)
2
*10=24.7inWC
Power: BHP(new)=(2750/1750)
3
*20=78BHP
ConfiguringVFDsforusewiththeLMV52
ModernVFDstypicallyhavehundredsofparametersthatcanbesettotailortheVFDtoaspecific
application.Asmentionedearlier,therearealsoatleastahundreddifferentmanufacturersofVFDs,
eachofwhichhavetheirownuniqueparameterlist.Duetothesetwofa ctors,SCCInc.offerspre‐
programmedVFDsthatcanbepurchasedwiththeVFDparameterssetupforusewithanLMV52.
IfaVFDforusewithanLMV52ispurchasedandpr
ogrammedindependently,thefollowingpointswill
serveasageneralguidelineforprogrammingtheVFDfortheLMV52application.Notethatthis
guidelineisnecessarilygeneralduetothevarietyofVFDs offeredinthemarketplace.
1. IfaVectorVFDisused(rec
ommended),setthe"ControlMethod"toOpenLoopVectormodeor
equivalent.
2. Thestoppingmethod(aftertherun/stopcontactisopened)shouldbesetto"CoasttoStop"tolet
themotorcoasttoastopafterpost‐purge.
3. Reverseoperation(theabi
litytoreversethemotorwith an input)shouldbedisabled.
4. ConfiguretheVFDtoacceptanexternalrun/stopsignalviathedrycontactontheLMV52.