ENGLISH
14
7.3.4 Y/STARTER:
Groundingofthecompletepumpsetwillbeperformedwith
specialcare.Earthingwillavoidanyelectrostaticaccumulationin
componentsofthepumpset.Eachpartofthepumpsetshouldbe
connectedtoearthwithacorrectlycalibratedbondingstraporcable
(motorwinding,motorframe,couplingguard,pumpbaseframe).
7.4 USEOFAFREQUENCYINVERTER
Whenpumpisusedwithavariablespeeddrive,makesurethat
thefrequencyinverterinstructionsandoperatingmanualis
availableandknown.
Theelectricmotorthatissuppliedwiththepumpmaybeconnected
underconditionstoaVSD.Variablespeedwillbeusedtoreachpump
requireddutypointonsite.Toensureareliableuseoftheequipmenta
fewprecautionsshouldbetaken:
Electricalrequirements:
Variablefrequencydrivewillnotgeneratevoltagepeakhigherthan
850V(motorphasesisolation)anddU/dtvalueshigherthan2500V/µs
(windingisolation).Ifthosevaluescanbereached,afiltershouldbe
installed:askinvertermanufacturerforproperselectionandmotor
manufacturerforlimitvalues.
ChooseavectorcontrolinverteroruseaquadraticV/Fcontrol
inverter.
Checkthatmotornominalvoltageisneverexceeded.
PowersupplycableshouldcomplytoATEXregulation.Ensurethat
motorwindingisequippedwithCTPtemperaturesensorsinside.
Aphysicalbarriershouldseparatepowersupplycablesandlow
voltagecablestoavoidanalogsignaldistortion.
Hydraulicrequirements:
Adedicatedsuctionpipeshouldbededicatedtoeachpumpusedwith
anegativesuctionhead(suctionlift).
CheckthatthepumpNPSH
R
atminimumspeedisalwayslowerthan
systemNPSH
A
.
Mechanicalrequirements:
Lowerspeedshouldnotfallunder40%ofpumpnominalspeedto
avoidanyvibrationsandanunstableflow.
TheharmoniccurrentsthatarecreatedbytheVSDpassthrough
motorballbearings.Standardballbearingscanbeusedupto
55KW.Forhigherinstalledpower(seeengravedpoweronmotorname
plate),themotorshouldbeequippedwithisolatedballbearings
(specificballbearing)orwithisolatedbearinghousing(andstandardball
bearing).
8 START‐UP
8.1 PRE‐COMMISSIONING
Ifthepumpisinstalledinapotentiallyexplosiveatmosphereor
whendangerousorpollutingfluidsarepumped,itisadvised(Zone
2)orrequested(zone1)toinstalladditionalprotectiondevices.
Checkfollowingpoints:
Pumpflowisalwayshigherthanauthorizedcontinuousminimumflow,
Pumpneverrunsdry,
Normalleakageoftheshaftsealiscontrolled,
Surfacetemperaturebearingshousingsislowerthanthemaximum
admissiblesurfacetemperatureinselectedATEXzone,
Pressureondischargesideofthepumpislowerthanpumpmaximum
allowableworkingpressure.
Setalarmandstoptripsofsensors.
Ineverycasescheck:
Qualityofelectricalconnections,
Protectiondevicesareinstalled,
Auxiliarypipingareconnected,
Flangesconnections,
Suctionlineandpumpcasingarefilledwithfluid,
Motordirectionofrotationiscorrect,
Couplingalignmentiscorrect,
Oillevelwascheckedandgreasingofballbearingshasbeendone,
Couplingguardisinstalled.
8.2 FILLING/VENTING
Beforetheveryfirststart‐up,pumpcasingandsuctionlinemustbefilled
withfluid(dependingonpipingsystemavacuumpumpmayhavetobe
used).
Pumpcasingshouldbeperfectlyventedtoavoidthatthe
mechanicalsealrunsdry.
Takeprecautionarymeasureswhenmanipulatingdangerous,hot,
coldorpollutingfluids.Wearingindividualprotectivedevicesis
necessary.TheoperatormustknownpotentialHazards.
8.3 START‐UP
Ifabarrierfluid,flushingfluid,coolingfluidoraheatingfluidis
used,checkthatauxiliarysystemsareactivatedandworking
correctlybeforepumpstart‐up.
Closeisolatingvalveonpumpdischargeside.
Openallvalvesinsuctionline.
Proceedtopumppriming(ifnotalreadydone).Pumpcasingand
suctionpipeshouldbecompletelyfilledwithfluid.
Turnthepumponandcheckdischargepressureincrease.Compare
thispressuretotheshutoffpressureavailableonthehydrauliccurve
Inordertoavoidanimportantoverheatingoftheliquidinsidethe
pumpthepumpshouldnotworkmorethan20to30seconds
againstacloseddischargevalve.
Ifexpectedpressureisreachedthenprogressivelyopenthedischarge
valve.
Ifthereisnoliquiddeliveredorifdischargepressureistoolow
thenseechapter“troubleshooting”.
8.4 RUNNINGCHECKS
Duringoperationofpumpindutyconditions(capacity,head,
temperature,…)thefollowingpointsmustbechecked:
Checkandnotepumpdutypoint.Ifnecessaryconvertpressurevalue
frombarindicatedonthepressuregaugetomwc:
HMT
mce
=(P
bar
x100)/(SGx9,806)withSG=fluidSpecificGravity.
Checkandnotecurrentconsumptiononeachphaseofthemotor.
Checkcalibrationofmotorprotections.
Checktemperatureofballbearings(onbearinghousingsurface).
Checkflexiblecouplingalignmentafterseveralpumpstarts(onlyfor
concernedpumpsvariants).
Checktighteningofflangesfasteningbolts.
Checkthereisnoleakageandnoabnormalrunningnoise.
Whenpumpinghotfluids,thedefinitivecouplingalignmentshould
bedoneonlywhensystemnominaltemperatureisreachedand
stabilized.Seechapter7.1.4COUPLINGALIGNMENT
Checkthesurfacetemperatureonthebearingbracketandonthe
pumpcasing.Checkpumpedfluidtemperature.Alarmandstop
tripssettingsshouldbedoneaccordingthosevalues.Refertospecific
sensorsIOMbeforeadjustingthosetrips.
Ifanexternalflushing,quenchoranexternalheatingisinstalled,the
followingpointsshouldbechecked:
Externalflushing:
Checkflushingpressureandcomparewithfollowingmaximumvalues:
Pressure:
Forimpellerdiameter125:P
suction
+0,5bar