Extech Instruments MA145 User manual

USERGUIDE
TrueRMS300AAC/DCMiniClampMeterwith
Non‐ContactVoltageDetector
ModelMA145
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MA145‐en‐GB_V1.15/15
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Introduction
ThankyouforselectingtheExtechMA145300AAC/DCTrueRMSMiniClampMeterwithNon‐
ContactVoltageDetector.TheMA145issmallinsizebutruggedinperformance.

TheMA145measuresAC/DCcurrentto300AandoffersaSmartDataHoldfeature,display
Backlight,In‐rushCurrentmode,DCAZero,LowPassFiltering(LPF),andanon‐contactVoltage
Detectionfeaturethatsenseselectricalsourcessafely.

Thisdeviceisshippedfullytestedandcalibratedand,withproperuse,willprovideyearsofreliable
service.Pleasevisitourwebsite(www.extech.com)tocheckforthelatestversionofthisUser
Guide,ProductUpdates,ProductRegistration,andCustomerSupport.
SafetyInformation–PleaseReadFirst
Toensurethesafeoperationandserviceofthemeter,followtheseinstructionsclosely.Failureto
observewarningscanresultinsevereinjury.
WARNINGS
WARNINGSidentifyhazardousconditionsandactionsthatcouldcauseBODILYHARMorDEATH.
IndividualprotectiveequipmentshouldbeusedifHAZARDOUSLIVEpartsintheinstallationwhere
measurementsaretobecarriedoutcouldbeaccessible.
Iftheequipmentisusedinamannernotspecifiedbythemanufacturer,theprotectionprovidedbythe
equipmentmaybeimpaired.
Toreducetheriskoffireorelectricshock,donotexposethisproducttorainormoisture.
Verifythemeteroperationbymeasuringaknownvoltage.Ifindoubt,havethemeterserviced.
Donotapplymorethantheratedvoltageasmarkedonthemeter.
Toavoidfalsereadingsthatcanleadtoelectricshockandinjury,replacebatteryassoonasthelow
batteryindicatorappears.
Donotusethemeterinoraroundexplosivegasorvapor.
Pleasekeepfingersandhandsbehindthefingerguards.
Donotexposemetertoextremesintemperatureorhighhumidity.
De‐energizetheinstallationundertestorwearsuitableprotectiveclothingwhenplacingorremoving
thecurrentclampfromatestsetup.
Donotapply/removethecurrentclampto/fromUNINSULATEDHAZARDOUSLIVEconductorswhichmay
causeelectricshock,electricburn,orarcflash.

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MA145‐en‐GB_V1.15/15
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CAUTIONS
CAUTIONSidentifyconditionsandactionsthatcouldcauseDAMAGEtothemeterorequipment
undertest.Donotexposethemetertoextremesintemperatureorhighhumidity.
SafetySymbolsthataretypicallymarkedonmetersandinstructions
Thissymbol,adjacenttoanothersymbol,indicatestheusermustrefertothe
manualforfurtherinformation.
Riskofelectricalshock
DonotapplyorremoveclampfromHAZARDOUSLIVEconductors
Equipmentprotectedbydoubleorreinforcedinsulation
Batterysymbol
ConformstoEUdirectives
Donotdiscardthisproductinhouseholdtrash.
ACmeasurement
DCmeasurement
Earthground

PERIEC1010OVERVOLTAGEINSTALLATIONCATEGORY
OVERVOLTAGECATEGORYI
EquipmentofOVERVOLTAGECATEGORYIisequipmentforconnectiontocircuitsinwhichmeasuresare
takentolimitthetransientover‐voltagestoanappropriatelowlevel.
Note–Examplesincludeprotectedelectroniccircuits.
OVERVOLTAGECATEGORYII
EquipmentofOVERVOLTAGECATEGORYIIisenergy‐consumingequipmenttobesuppliedfromthefixed
installation.
Note–Examplesincludehousehold,office,andlaboratoryappliances.
OVERVOLTAGECATEGORYIII
EquipmentofOVERVOLTAGECATEGORYIIIisequipmentinfixedinstallations.
Note–Examplesincludeswitchesinthefixedinstallationandsomeequipmentforindustrialusewith
permanentconnectiontothefixedinstallation.
OVERVOLTAGECATEGORYIV
EquipmentofOVERVOLTAGECATEGORYIVisforuseattheoriginoftheinstallation.
Note–Examplesincludeelectricitymetersandprimaryover‐currentprotectionequipment
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MA145‐en‐GB_V1.15/15
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Description

MeterDescription
1. Transformercurrentjaw
2. Finger‐HandGuard
3. Jawopeningtrigger
4. LCDMulti‐functiondisplay
5. Push‐buttoncontrols

Notethatthebatterycompartmentislocatedonbackofmeter

DisplayDescription
1. AutomaticACA/DCAdetect
2. Zeroicon
3. In‐RushCurrentmode
4. LowPassFilter
5. DataHold
6. ACMeasurement
7. DCMeasurement
8. Amperes(current)
9. MainDisplayarea
10. Batterystatusicon
11. Minus(negative)sign
12. Non‐ContactVoltDetecticons
ControlButtonDescription
Pressfor>2secondstoaccessIn‐rushCurrentmode
PresstoaccessLowPassFiltermode
Presstoaccesscurrentmeasurementmode.PressagaintotoggleAC/DC
PresstoaccessVoltagedetectmode
Pressfor>2secondstozeroDCAdisplay
PresstoswitchDataHoldonoroff
PresstopowerONthemeter.Pressandhold>2secondstoswitchOFF
Presstotoggledisplaybacklightonandoff
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MA145‐en‐GB_V1.15/15
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Operation
CAUTIONS

ReadandunderstandalloftheSafetystatementslistedinthesafetysectionofthismanual
priortouse.
PoweringtheMeter
1. PressthePower‐Backlightbuttontopowerthemeter.Checkthebatteriesiftheunitfailsto
powerON.
2. PressandholdthePowerbuttonformorethan2secondstopowerOFFthemeter.
3. ThemeterhasanAutoPowerOFFfeature(APO)wherethemeterswitchesOFFafter20
minutesofinactivity.TodisableAPO,refertothenextsection.
Note:Themeterdisplaysthebatterycapacitywhenpoweringup.
DisableAutoPowerOFF
ThemeterwillautopowerOFFafter20minutesofinactivity.Todefeatthisfeature,followthe
stepsbelow.
1. WiththemeterOFF,pressandholdthe‘V’buttonand,whilecontinuingtoholdthe‘V’
button,pressthepowerbutton.
2. ThedisplaywillshowAOFF.
3. Releaseallofthebuttons.
4. TheAutoPowerOFFfunctionwillnowbedisableduntilthenextcycleofpower.
DisplayBacklight
WiththemeterpoweredON,pressthebacklightbuttontoswitchthebacklightONorOFF.Note
thatexcessiveuseofthebacklightwillshortenthebatterylife.
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MA145‐en‐GB_V1.15/15
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AC/DCCurrentMeasurements
WARNING:Donothandlethemeterabovethefinger/handguardbarrier.
CAUTION:ObserveCATIII600VwithrespecttoEarthGroundfortheJaw.
1. Pressthe‘A’buttontoaccesstheCurrentmeasurementmode.TheAsymbolwillappearon
thedisplayinthelowerrighthandsideindicatingAmperes(Amps).
2. ThemetercanbeusedinAUTOmode(default)wherethemeterdetectsACorDCcurrent
automaticallyorthemetercanbeusedmanually(usethe‘A’buttontotoggleDCandAC).
3. WheninAUTOmode,thedisplayshowstheAUTOiconintheupperleftcorner.
4. ThemeterdisplaywillshowACorDContherightsideofthedisplay.
5. WheninDCCurrentmode,pressandholdZEROfor>2secondstonullthedisplaybefore
takingaDCAmeasurement.
6. Pressthejawtriggertoopentheclampjaw.
7. Positiontheclamparoundonlyoneconductor.Seeaccompanyingdiagramsforcorrectand
incorrectuse.
8. Readthecurrentinthedisplay.Thedisplaywillindicatetheproperdecimalpointandvalue.
InDC,Ifthepolarityisreversed,thedisplaywillshow(‐)minusbeforethevalue.
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MA145‐en‐GB_V1.15/15
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InrushCurrentMode
IntheInrushmodethemeterwaitsuntilatleast5Aisdetectedandthenstartsa100mssample
windowinwhichtocaptureaninrushcurrentRMSvalue.Refertoillustrationbelow.
1. PressandholdtheINRUSHbuttonfor>2secondstoaccesstheInrushCurrentmode.
2. ThedisplaywillshowtheINRUSHicon.
3. Whenready,takeacurrentmeasurement.Themeterwillcapturethehighestreading
detectedduringa100mswindow.Notethatthe100mswindowdoesnotopenuntilatleast
5Aisdetected.
4. ToexittheInrushCurrentmodepresstheINRUSHbuttonagainmomentarily.TheINRUSH
iconwillswitchOFF.
TIME
CURRENT
0A
Start Stop
Current
Detection
Threshold
Measured Inrush
Current
100ms Sample Window (60Hz)

LowPassFilter
TheLowPassFiltermodeoffershighfrequencyrejectionwhenmeasuringVariableSpeedDrives.
TheLowPassFiltermodeoffersacut‐offfrequencyof160Hz(approx.)withanattenuation
characteristicof‐24dbperoctave(approx.).
1. MomentarilypresstheLPFbuttontoaccesstheLPFmode
2. TheLPFdisplayiconisshownonthedisplayintheLPFmode
3. PresstheLPFbuttonagaintoexittheLPFmode,theLPFiconwillswitchOFF

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MA145‐en‐GB_V1.15/15
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Non‐ContactVoltageDetectionFeature
Themeter’saudiblebeepertriggersandthedisplayshows
dasheswhenthemetersensesanelectricalvoltagefield.The
highertheelectricalfieldstrengththegreaterthenumberof
dashesdisplayedandthefastertherateoftheaudiblebeeps.
Ifthemeterdoesnotemitatoneordisplaydashesinthismode,
thereisstillthepossibilitythatvoltageispresent.Pleaseuse
caution.
1. Pressthe‘V’buttontoaccesstheNon‐ContactVoltage
Detectmode.
2. Notethevoltagedetectiondisplayiconsasshowninthe
Descriptionsectionofthisguide.
3. Placethemeternearasourceofelectricalenergy.Thetip
oftheclampoffersthehighestsensitivity.
4. Notetheaudiblebeepingandthedashdisplays.
SmartDataHold
TofreezetheLCDmeterreading,presstheHOLDbutton.Whiledataholdisactive,theHOLD
displayiconappearsontheLCD.PresstheHOLDbuttontoreturntonormaloperation.The
HOLDiconwillswitchOFF.
Themeter’sbeeperwillsoundandtheLCDwillflashifthedetectedsignalis50countsgreater
thantheheldreading.



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MA145‐en‐GB_V1.15/15
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Maintenance
WARNING:Toavoidelectricalshock,disconnectthemeterfromanycircuitandturnOFF
themeterbeforeopeningthecase.Donotoperatewithanopencase.
CleaningandStorage
Periodicallywipethecasewithadampclothandmilddetergent;donotuseabrasivesorsolvents.
Ifthemeterisnottobeusedfor60daysormore,removethebatteriesandstorethemseparately.
BatteryReplacement
1. RemovethePhillipsheadscrewatthelowerbackofthemeter.
2. Openthebatterycompartment
3. ReplacethetwoLR44batteriesobservingcorrectpolarity.
4. Re‐assemblethemeterbeforeuse
5. Safety:Pleasedisposeofbatteriesresponsibly;neverdisposeofbatteriesinafire,batteries
mayexplodeorleak;nevermixbatterytypes,installnewbatteriesofthesametype.

Neverdisposeofusedbatteriesorrechargeablebatteriesinhouseholdwaste.
Asconsumers,usersarelegallyrequiredtotakeusedbatteriestoappropriate
collectionsites,theretailstorewherethebatterieswerepurchased,or
whereverbatteriesaresold.
Disposal:Donotdisposeofthisinstrumentinhouseholdwaste.Theuseris
obligatedtotakeend‐of‐lifedevicestoadesignatedcollectionpointforthe
disposalofelectricalandelectronicequipment.

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MA145‐en‐GB_V1.15/15
10
Specifications
ELECTRICALSPECIFICATIONS
FunctionRangeResolutionAccuracy(ofreading)
50~100Hz100~400Hz
ACCurrent
60.00A0.01 ±(1.5%+25digits)<3A
±(1.5%+5digits)≥3A
±(2.5%+25digits)<3A
±(2.5%+5digits)≥3A
300.0A0.1
FunctionRangeResolutionAccuracy(ofreading)
DCCurrent
60.00A(1)0.01 ±(1.5%+10digits)(2)
300.0A0.1 ±(1.5%+5digits)
(1)<0.3Avariationwhenmeasuringinvaryingdirections
(2) Add10dtoaccuracyinAUTOAC/DCsensemode
FunctionRangeResolutionAccuracy(ofreading)50Hz/60Hz
LowPassFilter
(LPF)
60.00A0.01 ±(3.5%+25digits)<3A
±(3.5%+5digits)≥3A
300.0A0.1
Cut‐offfrequency(‐3db):160Hz(approximately)
Attenuationcharacteristic:‐24dbperoctave(approximately)
FunctionRangeResolutionAccuracy(ofreading)
InrushCurrent300.0A0.1 ±(3.5%+5digits)
Integrationtime:100ms
Triggercurrent(threshold):5A
Voltage
Detector80V~600VACn/an/a
Thetipoftheclampofferstheoptimumsensitivity
Notes:
Clamppositionerror:±1.5%ofreading
Accuracyisgivenas±(%ofreading+leastsignificantdigit)at23C±5Cwithrelativehumidity
lowerthan80%.Accuracyisspecifiedforaperiodofoneyearaftercalibration.
ACAspecificationsareforACCoupled,TrueRMS.Forsquarewavetheaccuracyfor>100Hzis
unspecified.
Fornon‐sinusoidalwaveforms,additionalaccuracyCrestFactor(C.F.)considerationsexistas
detailedbelow:
Add3.0%forC.F.1.0~2.0
Add5.0%forC.F.2.0~2.5
Add7.0%forC.F.2.5~3.0
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