AEMC 6527 User manual

MEGOHMMETER 6527
ENGLISH User Manual
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Statement of Compliance
Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments
certifies that this instrument has been calibrated
using standards and instruments traceable to
international standards.
We guarantee that at the time of shipping your
instrument has met its published specifications.
An NIST traceable certificate may be
requested at the time of purchase, or obtained
by returning the instrument to our repair and
calibration facility, for a nominal charge.
The recommended calibration interval for this
instrument is 12 months and begins on the date of
receipt by the customer.
Serial #: ________________________________
Catalog #: 2126.53
Model #: 6527
Please fill in the appropriate date as indicated:
Date Received: _________________________________
Date Calibration Due: _______________________
Chauvin Arnoux®, Inc.
d.b.a AEMC®Instruments
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2 Megohmmeter Model 6527
Table of Contents
1. INTRODUCTION............................................................................... 4
1.1 International Electrical Symbols................................................5
1.2 DenitionofMeasurementCategories .....................................5
1.3 ReceivingYourShipment..........................................................6
1.4 OrderingInformation.................................................................6
1.4.1 AccessoriesandReplacementParts............................6
2. PRODUCT FEATURES ...................................................................... 7
2.1 Description................................................................................7
2.2 KeyFeatures ............................................................................7
2.3 ControlFeatures .......................................................................8
2.4 Display ......................................................................................9
2.5 ButtonFunctions.....................................................................10
2.6 Auto-OFFFunction .................................................................10
2.7 RangeSwitchPositions ..........................................................11
3. OPERATION .................................................................................. 12
3.1 StartingtheInstrument ...........................................................12
3.2 StoppingtheInstrument..........................................................12
3.3 InsulationResistanceTesting(MΩRange) ............................12
3.3.1 TestVoltage ................................................................12
3.3.2 SpotTesting ................................................................13
3.3.3 RatioTesting ...............................................................13
3.3.4 TipsForSuccessfulInsulationResistanceTesting .........14
3.3.5 InsulationMeasurement-Connections ......................14
3.3.6 InsulationResistanceMeasurementsonMotors........17
3.4 MeasuringMΩInsulationResistance .....................................19
3.5 VoltageMeasurements ...........................................................20
3.6 ContinuityMeasurements .......................................................21
3.6.1 LeadResistanceCompensation.................................22
3.7 ResistanceMeasurements .....................................................22
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Megohmmeter Model 6527 3
4. MAINTENANCE ............................................................................. 23
4.1 BatteryReplacement ..............................................................23
4.2 FuseReplacement..................................................................24
4.3 Cleaning..................................................................................24
5. SPECIFICATIONS........................................................................... 25
5.1 ReferenceConditions .............................................................25
5.2 Specications..........................................................................25
Limited Warranty ...................................................................................28
WarrantyRepairs...................................................................................28
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4 Megohmmeter Model 6527
CHAPTER 1
INTRODUCTION
WARNING
 ThisdevicecomplieswithsafetystandardIEC-61010-1.
 (Ed2–2001)forvoltagesupto600VincategoryIV,atanaltitudeofless
than2000m,indoors,withapollutionlevelofnotmorethan2.
 Thesesafetyinstructionsareintendedtoensurethesafetyofpersons
andproperoperationofthedevice.Ifthetesterisusedotherthanas
speciedinthisdatasheet,theprotectionprovidedbythedevicemay
beimpaired.
• Do not use the instrument in an explosive atmosphere or in the
presenceofammablegasesorfumes.
• Do not use the instrument on networks of which the voltage or
categoryexceedsthosementioned.
• Donotexceedtheratedmaximum voltages between terminals or
withrespecttoground/earth.
• Donotusetheinstrumentifitappearstobedamaged,incomplete,
ornotproperlyclosed.
• Beforeeachuse,checktheconditionoftheinsulationontheleads,
housing, and accessories.Any element of which the insulation is
deteriorated(evenpartially)mustbesetasideforrepairorscrapped.
• Useleadsandaccessoriesratedforvoltagesandcategoriesatleast
equaltothoseoftheinstrument.
• Observetheenvironmentalconditionsofuse.
• Donotmodifytheinstrumentanddonotreplacecomponentswith
“equivalents”.Repairsandadjustmentsmustbedonebyapproved
qualiedpersonnel.
• Replacebatteriesassoonasthe symbolappearsonthedisplay.
Disconnectallleadsbeforeopeningbatterycompartmentcover.
• Replace the defective fuse with a fuse having identical character-
istics. Disconnect all leads before opening the fuse compartment
cover.
• Usepersonalprotectiveequipmentwhenconditionsrequire.
• Whenhandlingprobesorcontacttips,keepyourngersbehindthe
guards.
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Megohmmeter Model 6527 5
1.1 International Electrical Symbols
Signifies that the instrument is protected by double or reinforced insulation.
This symbol on the instrument indicates a WARNING that the operator must
refer to the user manual for instructions before operating the instrument. In
this manual, the symbol preceding instructions indicates that if the instructions
are not followed, bodily injury, installation/sample and/or product damage may
result.
Compliance with the Low Voltage & Electromagnetic Compatibility European
directives (73/23/CEE & 89/336/CEE)
AC – Alternating current
AC or DC – Alternating or direct current
Risk of electric shock. The voltage at the parts marked with this symbol may be
dangerous.
Important instructions to read and understand completely.
Helpful information to acknowledge.
Ground/Earth symbol
In conformity with WEEE 2002/96/EC
1.2 Definition of Measurement Categories
CAT I: For measurements on circuits not directly connected to the
ACsupplywall outlet such asspeciallyprotected lines (mains)
derivedcircuits.
CAT II: Formeasurementsperformedoncircuitsdirectlyconnectedtothe
electrical distribution system (AC supply wall outlet). Examples
aremeasurementsonhouseholdappliancesorportabletools.
CAT III: For measurements performed in the building installation at the
distributionlevelsuchasonhardwiredequipmentinxedinstal-
lationandcircuitbreakers.
CAT IV: Formeasurementsperformedattheprimaryelectricalsupply
(<1000V)suchasonprimaryovercurrentprotectiondevices,
ripplecontrolunits,ormeters.
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6 Megohmmeter Model 6527
1.3 Receiving Your Shipment
Uponreceivingyour shipment, makesurethat the contentsareconsis-
tentwiththe packing list.Notifyyour distributor ofanymissing items. If
theequipmentappearstobedamaged,leaclaimimmediatelywiththe
carrierandnotifyyourdistributoratonce,givingadetaileddescriptionof
anydamage.Savethedamagedpackingcontainertosubstantiateyour
claim.
1.4 Ordering Information
MegohmmeterModel6527..................................................Cat. #2126.53
Includes set of two 5 ft color-coded leads (red/black) with alligator clips, 1 black test probe,
soft carrying case and a user manual.
1.4.1 Accessories and Replacement Parts
Lead–Setof2,Color-coded5ftSafetyLeads
w/Color-codedAlligatorClips(UL),&TestProbe ................ Cat. #2119.01
Case-ReplacementCarryingPouch.................................. Cat. #2126.75
Fuse-Setof5,0.5A,600V(min),HPC,6x32mm............... Cat. #2970.97
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Megohmmeter Model 6527 7
CHAPTER 2
PRODUCT FEATURES
2.1 Description
The Model 6527 is a portable multi-range megohmmeter capable of
measuringinsulationresistancefrom1kΩto 4000MΩ. It has three user
selectabletestvoltagesof250V,500Vand1000V.
The Model 6527 also features a continuity test function with audible
beeperforresistancesunder35Ω,andanoverloadprotectionof600Vrms.
Inadditionitcanmeasureresistanceupto400kΩ.
TheTESTbuttonhasanassociatedlockingfeatureforcontinuoustestsup
tothreeminutes,eliminatingtheneedtomanuallyholddownthebutton.
This lightweight, easy-to-use megohmmeter can be used for most
commonly performed insulation tests, such as on cables, switch gears,
motors,DCgenerators,powertoolsandsmallappliances.
2.2 Key Features
• Insulationtestvoltageselectionsof250V,500Vand1000V
• Measureinsulationto4000MΩ(4GΩ)
• TESTLOCKfeaturefortimesensitivemeasurements
• Autodischargeafterinsulationtest
• AC/DCvoltmeterto600VAC and 1000VDC
• Resistancemeasurementsupto400kΩ
• Continuitymeasurementswith200mAtestcurrent
• Test lead resistance compensation for accurate low resistance
measurements
• AutoHOLDfunctionto“freeze”readings
• Largeandbrightdualdisplaywithbluebacklight
• AutoPowerOff
• Ergonomicover-moldedcasewithback-stand
• ComplieswithInternationalInsulationTestingStandardsincluding
EN61557
• CEmarkedand600VCATIVrating
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8 Megohmmeter Model 6527
2.3 Control Features
HOLD ZERO /
MEGOHMMETER
MODEL 6527
TEST LOCK
TEST
500V
250V
OFF
k
MΩ
1000V
0.1M
0.2
0.5
25
>25V HOLD
LOCK
20 50
200 500
2000
1M
10M
100M
1000M
∞
1
2
3
4
Figure 2-1
1. VΩJack/COMinputjack
2. LCDDisplay(see§2.4)
3. DataHold,TestLockandZero/Backlightbuttons(see§2.5)
4. RotaryFunctionSwitch(see§2.7)
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Megohmmeter Model 6527 9
2.4 Display
0.1M
0.2
0.5
25
>25V HOLD
LOCK
20 50
200 500
2000
1M
10M
100M
1000M
∞
Figure 2-2
Symbol Description
Risk of electric shock
> 25V
Not used
LOCK
Test lock function enabled
Lead compensation for resistance measurements
Continuity measurement with buzzer
HOLD
Locking of the display
Indicates the battery is low and must be replaced (see § 4.1)
G
Giga-
M
Mega-
K
Kilo-
V
Volt
ΩOhm
AC
Alternating current
DC
Direct current
Indicates overload on the measured signal
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10 Megohmmeter Model 6527
2.5 Button Functions
Button Range Function
HOLD Any
Position
• Short Press: Holds the display of the measured value.
When activated, The HOLD symbol will appear and the
measurement is locked. To deactivate, press the HOLD
button again.
• Long Press: Deactivates the Auto-off function at start-up
NOTE: For insulation measurements, the HOLD feature is
automatically activated after each measurement.
TEST
LOCK
250V
500V
1000V
The Test Lock button allows the user to perform insulation
measurements in a permanent mode.
• Press the button once to turn the LOCK function ON.
• Press once again to turn the LOCK function OFF.
ZERO/
VAC
VDC
kΩ
• Short Press: compensates the measurement leads
(see §3.6.1)
Any
Position • Long Press: Activates/deactivates the backlighting
TEST
250V
500V
1000V
• Long Press: Starts the insulation measurement
NOTE: Press the button down until the insulation
measurement is stabilized. After each measurement, the
HOLD symbol is displayed.
2.6 Auto-OFF Function
TheModel6527automaticallyturnsoffafter10minutesofnon-use.At9
minutes,vebeepswarnthattheunitisabouttobeturnedoff.Toturnthe
megohmmeterbackon,turntherotaryswitchtoOFF,thentothedesired
function.
NOTE: Auto-off can be deactivated by pushing the HOLD button when
turningtherotaryswitchON.
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Megohmmeter Model 6527 11
2.7 Function Switch Positions
500V
250V
OFF
k
MΩ
1000V
Figure 2-3
Range Function
1000V
Insulation measurement at 1000V
500V
Insulation measurement at 500V
250V
Insulation measurement at 250V
OFF
Turns the instrument OFF
VAC
AC voltage measurement (V)
VDC
DC voltage measurement (V)
Continuity measurement with buzzer
k ΩResistance measurement
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12 Megohmmeter Model 6527
CHAPTER 3
OPERATION
3.1 Starting the Instrument
Turn the rotary switch to the appropriate function.All segments of the
display will light for a few seconds. The screen corresponding to the
chosen function will then appear. The megohmmeter is now ready for
measurements.
3.2 Stopping the Instrument
Toturnthemegohmmeteroffmanually,turntheswitchtoOFF.
Ifleftunusedfor10minutes,theunitwillturnoffautomatically.At9min-
utes,vebeepswarnthatthemegohmmeterisabouttobeturnedoff.To
turnbackon,pressanybuttonontheunit.
A long press on the HOLD button at startup deactivates the Auto-off
function.
3.3 Insulation Resistance Testing (MΩRange)
3.3.1 Test Voltage
Nopublished standard tells whichvoltageto choose foranygiven test.
However,publishedrecommendationscouldbesummarizedasfollows:
Rated Voltage of Motor Test Voltage
Below115 250V
115 250V or 500V
230 500V
460 500V or 1000V
Table 3-1
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Megohmmeter Model 6527 13
3.3.2 Spot Testing
Asageneralruleinspottesting,testvoltageshouldbeapplieduntilno
variation in reading is noted for 15 seconds, or applied for a xed 60
seconds.
What minimum value should be measured?
TheIEEEstandardNo.43-1974statesthatitisimpossibletospecifythe
valueofinsulationresistanceatwhichawindingwillfailelectrically,buton
motors,minimumreadingsgenerallystatedare:
Rated Voltage R Minimum
250 or less 2MΩ
460 2MΩ
Table 4-2
Thereisnoxedgurefordeterminingwhatisgoodandbadinresistance
readings,buta goodguidewouldbe1megohm foreveryonehundred
operatingvoltsapplied,asaminimumgure.Thisappliestomotorsand
transformers. When the insulation resistance gets this low, an electri-
calbreakdowncanbeexpectedatanytime,andrewindingorreplacing
shouldbeconsidered.
Itisnotunusualforawindingtobe10 to 100 times the recommended
minimumvalue(IEEEStd.#43-1974:Recommended Practice for Testing
Insulation Resistance of Rotating Machinery), but this varies with tem-
peratureandhumidity.
3.3.3 Ratio Testing
In timed resistance testing (Dielectric Absorption Ratio), readings are
takenat30and60secondstoobtainthedielectricabsorptionratio.
Insulationresistance@60s=DielectricAbsorptionRatio(DAR)
Insulationresistance@30s
Thistestisusefultoincreasetheaccuracyofspottesting.Ingeneral,a
ratioof1.25:2orbettershouldberequired.Aratiobelowthisindicatesthat
repairisprobablyneeded.
Remember,aDCinsulationtestmaybeusedforacceptancetesting,but
ismorecommonlyusedtocheckthegradualdeteriorationofequipment
overitslife.Consultyourequipmentmanufacturerforspecictestortest
voltageifnotknown.
Insulationresistancedecreaseswithmoisture,temperatureandageand
shouldberecordedovertimeatagiventemperatureandcorrected.
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14 Megohmmeter Model 6527
3.3.4 Tips For Successful Insulation Resistance Testing
• Check with the equipment manufacturer for factory insulation
resistancereadings.
• Donotrelyoninsulationresistancetestingaloneasproofofwind-
ingconditions.
• Donotexpectthesamevalueforallpartsofallmachines.
• Observe consistent test time duration, recognizing that total
currentthroughinsulationundertestwillvarywithtime.
• Correctallreadingsproperlytoastandardreferencetemperature
(seeIEEEStd.#43-1974,TemperatureCorrectionCurve).
• Knowwhatyouaretesting.Isolatethepieceofequipmentfrom
othercircuitry.
• Watchtrendsratherthanrelyingonsingle“spot”readings.
3.3.5 Insulation Measurement - Connections
Figure3-1showstheconnectionstomeasuretheinsulationofonecon-
ductortotheotherconductors.Thecableshouldbedisconnectedatboth
endstoavoidleakagethroughswitchboardsandpanels.
Cable Insulation
Conductor Under Test
+
-
Figure 3-1
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Megohmmeter Model 6527 15
Figures 3-2 and 3-3 show the connections for testing insulation from a
supplyconductortoground(e.g.amotorframe).
Cable Insulation
Conductor Under Test
+
-
Figure 3-2
Cable Insulation
Conductor Under Test
+
-
Figure 3-3
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16 Megohmmeter Model 6527
Figure3-4showstheconnections
to a transformer (lighting or
distribution).
Makesurethattheswitchesand/
orcircuitbreakersonbothsides
areopen.
Check the high voltage winding
toground,lowvoltagetoground,
andtheresistancebetweenthem
withnowindinggrounded.
Tested Winding
Transformer
Grounding Lug
+
-
Figure 3-4
~
~
~~
~
~
Jumpers
+
-
Figure 3-5
Figure3-5 shows theconnections
for measuring the insulation of
a three-phase line to ground by
connecting the jumpers between
phases.
This gives a reading of all
conductorsatonce.Ifaloadsuch
asamotor,heater,etc.,isattached
to the other end of the line, it will
readtheloadresistancetoground
atthesametime.
Byremovingthejumpers,readings
canbemadebetweentheindivid-
ualconductorsandground.
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Megohmmeter Model 6527 17
3.3.6 Insulation Resistance Measurements on Motors
Figure3-6showsreadingtheresistancetogroundofathree-phasemotor
winding.Sincethethree-phasemotorsareinternallyconnected,itisonly
necessarytoconnectoneleadtothemotorleadandtheotherleadtothe
motorframeasshown.
+
-
Figure 3-6
Figure 3-7 shows the
windings of a three-
phasemotorseparated.
Sometimes this can be
done at the lead termi-
nals, while other times
the end bells must be
removed to get at the
leadwiresofthecoils.
Byconnectingthemego-
hmmeter as shown, the
phase insulation resis-
tancevaluecannowbe
determined.
Read between phases
“A”and“B”,then“B”and
“C”,then“C”and“A”.
A
B
C
+
-
Figure 3-7
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18 Megohmmeter Model 6527
Figure 3-8 shows connec-
tions for testing insulation
fromasupplyconductorina
switchbox to ground (motor
frame). An identical test
maybecarriedoutfromthe
motor starter.
Motor Side
of Switch:
Connection
to One Leg
Grounded
Motor Frame
Starter In
+
-
Figure 3-8
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