Kyoritsu Electrical Instruments Works, Ltd. KEW3431 User manual

Instruction Manual
Compact Insulation resistance tester
KEW3431

Contents
1. Safetywarnings･･･････････････････････････････････････ 1
2. Features･･････････････････････････････････････････････ 5
3. Specifications･････････････････････････････････････････ 6
4. Instrumentlayout･･････････････････････････････････････ 9
5. Accessories･･････････････････････････････････････････ 11
6. Gettingstarted･･･････････････････････････････････････ 12
6-1 Mechanicalzeroadjustment････････････････････ 12
6-2 Attachingmetaltip/adaptertotestleads････････ 12
6-3 Batteryvoltagecheck･･････････････････････････ 13
7．Voltagemeasurement･････････････････････････････････ 14
7-1 Measurementmethod･･････････････････････････ 14
8. Insulationresistancemeasurement･････････････････････ 15
8-1 Measurementmethod･･････････････････････････ 18
8-2 Continuousmeasurement･･････････････････････ 19
8-3 Outputvoltagecharacteristics･･････････････････ 20
8-4 LEDinsulationstatusindicator･････････････････ 21
9. ScalelightandLEDlight･･････････････････････････････ 22
10.
HowtodisableLEDinsulationstatusindicator&auto-lighting ･･ 23
11.Batteryreplacement ･･････････････････････････････････ 25
12.Shoulderstrapbeltattachment･････････････････････････ 26
13.StoringinCarryingcase･･･････････････････････････････ 27
14.Cleaningmetercover･････････････････････････････････ 28


1

1. Safety warnings
This instrument has been designed, manufactured and tested
according to IEC 61010: Safety requirements for Electronic
measuring apparatus, and delivered in the best condition after
passingqualitycontroltests.
This instruction manual contains warnings and safety rules which
have to be observed by the user to ensure safe operation of the
instrument and to maintain it in safe condition. Therefore, read
through these operating instructions before starting to use the
instrument.
#  DANGER
●Read through and understand the instructions contained in this
manualbeforestartingtousetheinstrument.
●Keep the manual at hand to enable quick reference whenever
necessary
●Theinstrumentistobeusedonlyinitsintendedapplications.
●Understandandfollowallthesafetyinstructionscontainedinthe
manual.
Itisessentialthattheaboveinstructionsareadheredto.Failureto
followtheaboveinstructionsmaycauseinjury,instrumentdamage
and/or damage to equipment under test. Kyoritsu is by no means
liableforanydamageresultingfromtheinstrumentincontradiction
tothesecautionarynotes.
The symbol#indicated on the instrument, means that the user
must refer to the related parts in the manual for safe operation of
the instrument. It is essential to read the instructions wherever the
symbolappearsinthemanual.
#DANGER：is reserved for conditions and actions that are
likelytocauseseriousorfatalinjury.
#WARNING：is reserved for conditions and actions that can
causeseriousorfatalinjury.
#CAUTION：is reserved for conditions and actions that can
causeinjuryorinstrumentdamage.


2

#  DANGER
●Never makemeasurementsoncircuitsinwhichearthpotentials
higherthan600Vexist.
●
KEW3441isaCATIII-ratedinstrument.Donotmakemeasurements
under the circumstances exceeding the designed measurement
category.
●Do not attempt to make measurements in the presence of
flammable gasses. Otherwise the use of the instrument may
causesparking,whichcanleadtoanexplosion.
●
Neverattempttousetheinstrumentifitssurfaceoryourhandiswet.
● Becarefulnottoshort-circuitthepowerlinewiththemetalpartof
thetestleadduringameasurement.Itmaycausepersonalinjury.
● Donotexceedthemaximumallowableinputofanymeasuringrange.
● Neveropenthebatterycompartmentcoverduringameasurement.
●Theinstrument shouldbeusedonlyinits intendedapplications
or conditions. Otherwise, safety functions equipped with the
instrument do not work, and instrument damage or serious
personalinjurymaybecaused.
●Verify proper operation on a known source before use or take
actionasaresultoftheindicationoftheinstrument.
#  WARNING
●Never attempt to make any measurements if any abnormal
conditions, such as a broken cover or exposed metal parts are
presentontheinstrumentandtestleads.
●Ensurethatthetestleadsarefirmlyconnectedtotheinstrument,
andthenpressthetestbutton.
●Do not install substitute parts or make any modifications to
the instrument. Return the instrument to your local KYORITSU
distributorfor repair or re-calibration incase of suspected faulty
operation.
●
Donottrytoreplacebatteriesifthesurfaceoftheinstrumentiswet.
●Connectthetestleadsfirmlyintoeachterminal.
●SetthefunctionswitchtoOFFpositionwhenopeningthebattery
compartmentcoverforbatteryreplacement.
●Neverrotatethefunctionswitchwiththetestleadsconnectedto
theequipmentundertest.


3

#  CAUTION
●Always make sure to set the function switch to the appropriate
positionbeforemakingameasurement.
●Power off the instrument after use. Remove batteries if the
instrumentistobestoredandwillnotbeinuseforalongperiod.
●Donotexposetheinstrumenttodirectsunlight,hightemperature,
humidityordew.
●Useadampclothwithneutraldetergentorwaterforcleaningthe
instrument.Donotuseabrasivesorsolvents.
●Thisinstrument isnot water-proof.Donotlettheinstrumentget
wetwithwater;otherwiseitmaycausemalfunction.
●Iftheinstrument is wet, makesure to let itdry before putting it
intostorage.
●
Keepyourhandandfingersbehindthebarrierduringameasurement.
Symbols
Thefollowingsymbolsareusedandmarkedontheinstrumentandin
theinstructionmanual.Pleasecarefullycheckbeforestartingtouse
theinstrument.
CATⅢ
Primary electrical circuits of the equipment connected
directly to the distribution panel, and feeders from the
distributionpaneltooutlets.

Doubleorreinforcedinsulation
#
User must refer to the explanations in the instruction
manual.

Earth
Dangerofpossibleelectricshock


4

MeasurementCategory
To ensure safe operation of measuring instruments, IEC 61010
establishes safety standards for various electrical environments,
categorizedasO to CAT IV, and called measurement categories.
Higher-numberedcategories correspondtoelectrical environments
with greater momentary energy, so a measuring instrument
designed for CAT III environments can endure greater momentary
energythanonedesignedforCATII.
O :Circuits which are not directly connected to the mains
powersupply.
CATII :Electrical circuits of equipment connected to an AC
electricaloutletbyapowercord.
CATIII:Primary electrical circuits of the equipment connected
directly to the distribution panel, and feeders from the
distributionpaneltooutlets.
CATIV:Thecircuitfromtheservicedroptotheserviceentrance,
and to the power meter and primary over-current
protectiondevice(distributionpanel).
O: Device which is
not directly
connected to the
mains power supply


5

2. Features
KEW3431 can measure insulation resistance and also AC/DC
voltageonlow-voltageinstallationsof600Vorless.
●Designedtomeetthefollowingsafetystandards
IEC61010-1,IEC61010-2-030CATIII600VPollutiondegree2
IEC61010-031
●Compactandlightweightdesign
●Scale light and LED spot light to facilitate working at dimly
illuminated location or at nighttime work. Built-in illuminance
sensorautomatically turns onoff the lights.Auto-light-off function
isalsoavailabletoturnofftheselightsautomaticallyifthefunction
switch is not moved or the test button is not pressed for two
minutes.Theauto-lightingfunctioncanbeturnedoff.
●Test probe with remote control switch is supplied as standard
accessory
●Shoulderstrapforboth-handsoperation
●User-changeabletestprods
●LivecircuitwarningwithblinkingLEDandbuzzer
●Voltagemeasurement
・AC/DCautodetection
・Livecircuitwarningforavoltageinputof30Vorhigher
●Insulationresistancemeasurement
・Withauto-dischargefunction
When an insulation resistance like a capacitive load is
measured, electric charges stored in capacitive circuits are
automatically discharged after measurement. Discharge can be
checkedwiththewarningLEDandbuzzer.
・Withalarmfunction
The LED indicates whether a measured value is less than or
higherthanthereferencevalue.Forfurtherdetail,see8-4.LED
insulation status indicator in this manual. This function can be
turnedoff.
・Safetyrangebetween500Vand1000Vranges
・Discontinuouswarning buzzer soundswhen the functionswitch
issetto1000Vrange.


6

3. Specifications
●Measuringrangeandaccuracy（23ºC±5ºC,RH85%orless）
[Voltagemeasurement]
Measurement
voltage 0〜600V
Accuracy within±5%ofthemaximumscalevalue
※
 Foraninputvoltageof30Vormore,theinstrumentautomatically
judgesACorDCandindicatestheresultwiththeLED.
ForACvoltage:RedLEDlightsup.
ForDCvoltage:OrangeLEDlightsup.
（TheLEDdoesntlightupifinputvoltageislessthan30V.）
[Insulationresistancemeasurement]
Ratedmeasurement
voltage 250V 500V 1000V
Max.effectivescale
value 200MΩ 200MΩ 2000MΩ
Accuracyinfirst
effectivemeasuring
ranges
0.1to100MΩ 1to1000MΩ
within±5%ofindicatedvalue
Accuracyinsecond
effectivemeasuring
ranges
within±10%ofindicatedvalue
※measuring ranges other than above, 0 and
∞ticks
Accuracyat0&∞ within±0.7%ofscalelength
Open-circuitvoltage
100%to120%ofratedmeasurementvoltage
Ratedmeasurement
current 1mA,0%to+20%
Short-circuitcurrent within1.5mA


7

●Applicable
standards
●IEC61010-1,2-030CATIII600V
Pollutiondegree2
●IEC61557-1,-2
●IEC60529IP40
●IEC61326-1,2-2
●IEC61010-031
MODEL7260…CATIII600V(w/cap)
 CATII1000V(w/ocap)
 CATII1000V(w/8017A)
(Attachthesuppliedprotectivecaptousethis
testleadsinCATIIIorhigherenvironments.)
MODEL7261A …CATIII600V(w/alligatorclip)
 CATII600V(w/flattestbar)
(Attachthealligatorcliptousethistestleads
inCATIIIorhigherenvironments.)
※Whentest probes,sometimes withmetal tips,
are connected and used with the instrument,
the measurement category and voltage rating
ofthelowestrateditemisapplied.
●Locationforuse Altitude2000morless,in-dooruse
●Operatingtemp.
&humidityrange 0ºCto40ºC,80%orless(nocondensation)
●Storagetemp.
&humidityrange -10ºCto50ºC,75%orless(nocondensation)
●Withstand
voltage
5160VAC(50/60Hz)/5sec
Betweenelectricalcircuitandenclosure
●Insulation
resistance
50MΩormore/1000VDC
Betweenelectricalcircuitandenclosure
●Auto-power-off Turns off the instrument automatically, after a
beepsound,ifthereisnofunctionchange,range
changeorbuttonpressforabout10min.
(※notworkduringameasurement)
●Scalelight/
LEDlight
Automaticallyturns offifthere isnoactivity for
about2min.(※disabledduringameasurement)
●Dimensions 97(L)×156(W)×46(H)mm
●Weight Approx.430g(includingbatteries)
●Powersource FoursizeAAbatteries
※Useofalkalinebatteryisrecommended.


8

●Operatinguncertainty(IEC61557-2)
Operating uncertainty (B) is an error obtained under the nominal
operating conditions, and calculated with the intrinsic error (A),
whichisanerroroftheinstrumentused,andtheerror(En)dueto
variations.AccordingtoIEC61557-2,themaximumoperatingerror
should be within ± 30%. Intrinsic error (A) is uncertainty of the
performancecharacteristicsofinsulation resistancetesters inthe
referencecondition.
※Formula:B=±(｜A｜+1.15x√E1
2+E2 2+E3 2)
A Intrinsicerror
E1Influenceofposition(referenceposition±30°)
E2
Influenceofsupplyvoltage
(untilredLEDbatterystatusindicatorlightsup)
E3Influenceoftemperature(0ºC〜40ºC)
Thespecsofthisinstrumentareasfollows.
Intrinsicerror(A)…………………within±5%ofindicatedvalue
(coveragefactor:k=2)
Influenceofposition(E1)…………within±15%ofindicatedvalue
Influenceofsupplyvoltage(E2)…within±5%ofindicatedvalue
Influenceoftemperature(E3)……within±5%ofindicatedvalue
Max.operatinguncertainty(B)…24%
※The measuring range to keep the max. operating uncertainty is
thesameasthe1steffectivemeasuringrange.
●Possiblenumber ofmeasurements wherebattery voltageis within
theeffectiverange(measurementof5sec.,pauseof25sec.)
Function Testresistor Possiblenumberof
measurements
250V 0.25MΩ Approx.2000times
500V 0.5MΩ
1000V 1MΩ Approx.1000times
※incaseofusingalkalinebatteries


9

②
Fig. 4-1
①
③
④
⑥⑦⑤
⑧
⑨
⑩
⑤
4. Instrument layout
(1)Frontpanel
Name Description
①
Meterzeroadjuster Adjuststhepointerposition.
② Pointer Indicatesthemeasuredvalues.
③ Testbutton
Starts/ stops measurement. For continuous
measurement, press and turn the button
clockwisetolockitintheoperatingposition.
④
Illuminancesensor
Detects ambient brightness to turn on/ off
thelights.
⑤LEDinsulation
stateindicator
GreenLEDlightsup:
measuredvalue>presetreferencevalue
RedLEDlightsup:
measuredvalue<presetreferencevalue
⑥Insulation
resistancescale
Indicatesthemeasuredinsulationresistance
values.Colorcodedscalesforeasyreading.
⑦ Voltagescale Indicatesthemeasuredvoltagevalues.
⑧ LivewarningLED Red LED lights up for AC voltage and
orangeLEDforDCvoltage.


10

① ②
Fig. 4-2
③
⑨
LEDbatterystatus
indicator
Indicatesbatteryvoltagelevel.
Solidgreen :Enough
Blinkinggreen :Low
Solidred :Almostexhausted
⑩ Functionswitch
Switches measurement functions and selects
voltageforinsulationresistancemeasurement.
(2)Sidepanel
Name Description
① LINE TerminalforMODEL7260testlead
② EARTH TerminalforMODEL7261Atestlead
③ LEDlight
Illuminates the point to be measured. The light
automatically turns on/ off depending on the
ambientbrightness.


11

Fig. 5-3
※1 Barrier ※1 Barrie
＋
＋
L-shaped
Banana plug
5. Accessories
●Testleads
(1)TestleadMODEL7260withremotecontrolswitch(red)
(2)ExtensionprodMODEL8017A
※AttachedandusedwithMODEL7260.
Blackcordwithbananaplugsatbothends
Alligatorclip Flattestbar
※1Barrier is a part providing protection against electrical shock
andensuringtheminimumrequiredairandcreepagedistances.
●Otheraccessories
(1)CarryingcaseMODEL9173
(2)ShoulderstrapMODEL9121
(3)FoursizeAAalkalinebatteries
(4)Instructionmanual
(3)AsetoftestleadswithalligatorclipMODEL7261A
Fig. 5-1
※1 Barrier
Metal tip
Insulation cap
Rating of measurement category of
the test lead depends on attaching/
removingtheinsulationcap.
CATIII600V(w/cap)
CATII1000V(w/ocap)
Longtypeandhelpfultoaccess
thedistantmeasurementspot
Fig. 5-2


12

6. Getting started
6-1 Mechanicalzeroadjustment
With the function switch set to OFF position and without pressing
the test button, turn the zero adjuster with a screwdriver so that
thepointer linesup withthe∞markontheinsulationresistance
scale. In case the instrument is used at sloping place, ensure that
thepointerlines up with the∞mark tilting the instrument tothe
necessaryangle.
6-2 Attachingmetaltip/adaptertotestleads
Thefollowinguser-changeablemetaltipsandadaptersareavailable.
(1)IncaseofMODEL7260:

The metal tip of MODEL7260 is replaceable depending on the
applications.
1.Standardmetaltip…Installed at a shipment supplied with
detachableinsulationcap
2.MODEL8017A
 …… Longtypeandhelpfultoaccessthedistant
 [Howtoreplacetheparts]
 Turn the tip of MODEL7260 counter-clockwise and remove the
metaltip.Insert the metal tip you want to useintothe hexagon
hole,andturnthetippartoftheprobeclockwisetotightenfirmly.
(2)IncaseofMODEL7261A:

EitherofthefollowingadapterscanbeattachedtoMODEL7261A.
1.Alligatorclip
2.Flattestbar
MODEL 8017A
Fig. 6-1
Standard metal tip
Metal tip
Male screw
Hexagon hole
Female screw


13

[Howtoattach]
Firmlyinsertandconnecttheadaptertotheendofthecord(with
bananaplugsatbothends).
#  DANGER
To avoid getting electrical shocks, ensure that test leads are
disconnected from the instrument when replacing the metal tip or
adapterfortestleads.
6-3 Batteryvoltagecheck
(1)Please refer to11. Battery replacementin this manual and
insertbatteriesinKEW3431.
(2)SetthefunctionswitchtoanypositionotherthanOFFtopower
ontheinstrument.
(3)CheckthecolorofLEDbatterystatusindicator.
Solidgreen:Batteryvoltageisenough.
Blinkinggreen:Batteryvoltageislow.
 Replacebatterieswith reference to11. Battery replacement
toperformfurthermeasurements.
 Solidred:Batteryvoltageisbelowthelowerlimitoftheoperating
voltage. In such a condition, accuracy of the measured result
isntguaranteed.Replacethebatterieswithnewonesassoon
aspossible.
●ColorofLEDbatterystatusindicatormightchangefromgreento
red depending on measured objects; for example, resistance of
themeasuredobjectislow.
●Use of AA alkaline battery is recommended. Use of other
batteriesmaycauseimproperindicationofbatterylevel.
Banana plugs, both ends
Fig. 6-2
Flat test bar
Alligator clip


14

Fig. 7-2
7. Voltage measurement
#  DANGER
●Do not apply a voltage exceeding the maximum allowable input
(600V)totheinstrument.
●Keepyourfingersbehindthebarrierduringameasurement.
●Verifyproperoperationon aknownsourcebefore takingactions
asaresultoftheindicationoftheinstrument
7-1 Measurementmethod
SetthefunctionswitchtoVAC/DCpositiontomeasurevoltage.
(1)Connectthetestleadsasthefollowingfigureshows.
・MODEL7260toLineterminal
・MODEL7261AtoEarthterminal
(2)Connecttheblacktestleadtotheearthsideofthecircuitunder
testandtheredremoteprobetothelineside.
Fig. 7-1
Red Black


15

(3)CheckthereadingontheLCDwithoutpressingthetestorremote
control button. The instrument detects AC/DC automatically,
andturnsontheredLEDforacinputandtheorangeLEDfordc
input.
・When the measured voltage is less than 30V, AC/DC auto-
detectdoesntwork.
#  CAUTION
Thepointersweepsdependingontheappliedinputevenwhilethe
instrumentispoweredoff;however,accuracyisnotguaranteed.In
thisstate,livewarningLEDdoesntlightup.Ensuretheinstrument
ispoweredontomeasurevoltage.


16

8. Insulation resistance measurement
This instrument isused tomeasure insulation resistancein electric
applianceorcircuittoinspecttheinsulationperformance.Checkthe
voltageratingoftheobjecttobetestedbeforemakingmeasurement
andselectthevoltageappliedto.
Note:
●Depending on the object to be measured, displayed insulation
resistancevaluemaynotstabilize.
●The instrument may give bleep during an insulation resistance
measure-ment,however,thisisnotamalfunction.
●Measurement time may be longer when measuring capacitive
load.
●Ininsulationresistancemeasurement,theearthterminaloutputs
positivevoltageandthelineterminalnegativevoltage.
●Connect the earth cord to the earth (ground) terminal at
measurement. It is recommended to connect the positive side
to the earth side when measuring insulation resistance against
groundorwhenapartoftheobjectundertestisearthed.Such
connection is known to be more suitable for insulation testing
since insulation resistance values measured with the positive
side connected to earth are typically less than those taken
throughthereversedconnection.
#  DANGER
●Be extremely careful not to touch the tip of test probe or
circuit under test to avoid electrical shock during insulation
measurement as high voltage is present on the tip of the test
probecontinuously.Wipethetestprobewithasoftcloth,ifitis
wet,anduseitafteritsdry.
●Never make measurements with the battery compartment cover
removed.
#  CAUTION
Always disconnect power to the conductor under test before
starting insulation measurement. Do not attempt to make
measurements on a live conductor. Otherwise, it may damage the
instrument.


17

8-1 Measurementmethod
(1)Connectthetestleadsasthefollowingfigureshows.
・MODEL7260toLineterminal
・MODEL7261AtoEarthterminal
(2)Confirm the circuit under test is not energized, and measure
voltagewithreferenceto7.Voltagemeasurement.
(3)Confirm the voltage value which can be applied to the object
undertest,andthensetthefunctionswitchtoadesiredrange.
●Thereisanemptyrangebetween500Vand1000Vforsafety
purpose. If the function switch is set to this safety position,
theinstrumentdoesntstartameasurementalthoughthetest
buttonispresseddown.
●Discontinuouswarningbuzzersoundswhenthefunctionswitch
issetto1000Vrange.
(4)Connecttheearthtestlead(MODEL7261A)totheearthterminal
ofthecircuitundertest.ThelivewarningLEDblinksandbuzzer
soundsifavoltageof30Vorhigherexistsinthecircuit.Pressing
thetestbuttoninthisstatedoesntstartresistancemeasurement.
(5)Placethe tipofremote probe(line) tothecircuitundertest and
pressthetestbuttonorremotecontrolswitch.
Fig. 8-1
Red Black


18

(6)Autodischargefunction
This function allows electric charges stored in the capacitance
of the circuit under test to be automatically discharged after
measurement. Set the test button or remote control switch to off
withthetestleadsconnected.Dischargecanbecheckedwiththe
meter,blinkingLEDandbuzzer.
[Displayexample]
(7)Power off the instrument when measurement completes, and
disconnectthetestleads.
Resistance Value＝Voltage／Current
ＲＸ＝Ｖ／Ｉ
Principle of insulation
resistance measurement
Fig. 8-2
Fig. 8-3
Fig. 8-4