High Voltage VLF-CM Series Mode d’emploi
Safety,Operation,andProcedureInstructionsfortheVLFSeriesof
ACHipots
Danger- Lethal Voltages:
Equipment to be used by trained personnel only
This Operator Manual contains instructions for the operation of a High Voltage power source. The operator of this equipment
must use good judgement and follow all safety precautions noted in this guide to ensure the protection of himself and others in
closeproximitytothetestarea. Failure to follow the instructions could result in injury
or death. Proper grounding of the test set must be done prior to
connecting this unit to a power source.
Min
e
VL
F
-
CM
SERIES
Please Refer to
Documentation
Before Operation
VLFOperatorManual
HIGH VOLTAGE, INC.
31CountyRoute7A
Copake,N.Y.12516
Phone518/329-3275•Fax518/329-3271
http://www.hvinc.com
E-Mail: [email protected]
Last saved 10/5/2016
T:\DOCUMENTS\Manuals\VLF\MANvlf90CMFRf_2k16.doc
Very Low Frequency (VLF) AC High Voltage Testing - Operators Manual Addendum
Instrument Summary
This instrument is a Very Low Frequency AC high voltage test system – a VLF hipot. It is an AC hipot whose frequency
output is 0.1 Hz or lower, compared to the 50/60 Hz of a conventional AC hipot. The lower the frequency, the lower the
current and power it takes to test a capacitive load like a cable. At 0.1Hz, it takes 600 times less current and power,
compared to 60Hz, to apply an AC voltage to a cable or some other high capacitance load.
At 0.1Hz frequency output, one full cycle of the sine wave takes 10 seconds, 20 seconds at 0.05Hz, and 50 seconds at
0.02Hz. Even though each cycle of the waveform can take 10 seconds or longer, it is still alternating current – AC – and is
sinusoidal.
This is not a DC hipot and it does not operate in the same manner. When the voltage output is raised, the voltage will
climb to its peak and then descend back to zero. The output polarity of the set reverses (a solenoid switch can be heard)
and then climbs again in the opposite polarity. This rise and fall of the voltage is obvious on the voltmeter and is normal.
The current meter will also rise and fall as the cable charges and discharges every half cycle. Unlike DC, there are no
leakage currents to read. This is a go/no-go, or pass/fail, AC stress test. The load under test either withstands the test
voltage and passes, or it breaks down and fails.
Important note: Use the VLF test set properly. Test at the proper test voltage and time duration. Abbreviated tests or
tests at reduced voltage levels should not be performed. An improper test may aggravate cable defects that may cause
cable failure later in service. The proper test voltage and time duration are essential to allow the VLF to do its job.
Helpful Notes to Users
Peak Voltage: The Voltmeter on the VLF test set measures the Peak voltage. It is the peak output voltage that is used
during VLF testing. If your test specification indicates a test voltage in RMS, multiply by 1.414 to obtain the peak value for
the test. The IEEE400.2 chart indicating test voltages for different cable ratings shows both rms and peak. All other AC
hipoting using 50/60 Hz instruments is measured by the rms voltage, not VLF testing, so make sure this issue is
addressed.
Output Frequency: All VLF sets are rated by the uF of load they can test at a given frequency. The lower the frequency,
the higher the capacitance, or the longer the cable, can be tested. Always use the highest frequency possible. Testing
should be performed at 0.1Hz, unless the capacitance of the load is too high for the uF rating of the set at 0.1 Hz. It may
be necessary to reduce the frequency to 0.05, 0.02, or 0.01 Hz depending on the capacitance of the load. The load
capacitance can be measured using the capacitance meter of the VLF or be calculated, if the capacitance per foot or
meter is known. Example: At 0.1Hz, 1 – 2 miles of cable can be tested, depending on size.
Test Duration: The recommended test duration is 30 minutes as a minimum. In the body of this manual are reprints from
the IEEE400.2 standard discussing this issue and additional information on the subject. The longer the test duration the
better, as minor defects that triggered into partial discharge due to the test voltage will have time to grow through to failure
during the test. The duration indicated in the standard is based on using a frequency of 0.1Hz. If lower frequencies are
used, the test time must be extended. Rather than 30+ minutes at 0.1Hz, perhaps 60 minutes should be used at 0.05 and
0.02Hz.
Cable Failure Indication: When the cable fails, the thermal Overload on the front panel will pop up. Also, the Voltage and
Current meters will read erratically as the cable arcs. It may take several cycles of the voltage rising to the arc-over
voltage of the fault to cause the thermal overload to warm up enough to trip.
Know Your Test Equipment – Read the Operators Manual
Last saved 10/5/2016
T:\DOCUMENTS\Manuals\VLF\MANvlf90CMFRf_2k16.doc
TableofContents
About the Operator Manual 1
SECTION 1
General Information 2
Features and Specifications 2-5
Controls and Indicators 6-9
List of Components 10
SECTION 2
Setting up the Equipment 11,12
Typical VLF Connection Scheme 13
VLF with Cable Reel Connection Scheme 14
Operating the Equipment 13-18
VLF Cable Testing recommendations 19,20
Blank Page for Notes 21
SECTION 3
Performing Special Operations 22
Voltmeter Re-calibration 22,23
Miscellaneous 23
Yearly Maintenance 23
Return Material 24
Warranty 25
OPERATOR MANUAL
- 1 -
AbouttheOperatorManual
Important
ThisOperator Manual describes the featuresand safe operationof a High
VoltageACTestSet.Theinstructions are intendedto be clear andsimple,
but theoperator mustbe trainedand qualified according to the customer’s
establishedprocedures for the use ofthis type ofequipment.
This Operator Manual is organized to provide information on the VLF Series in steps that familiarize the new
operatorwiththe entire scope ofoperationofthistestset.
Section1:SpecificationsandControls.
Section2:SetupandOperation.
Section3:Performing Special Operations.
TheFunctions,Features,andSpecifications oftheVLFSeriesofACHipotsarealsodiscussedintheVLFBrochure
availablefromHighVoltage,Inc.
OPERATOR MANUAL
- 2 -
GeneralInformation
Thissectionfamiliarizestheoperatorwiththe features andspecificationsofthe
VLF Series ofPortable AC Hipots manufactured by HIGH VOLTAGE, INC.
FeaturesandSpecifications
The VLF Series of hipot test sets provide true sine wave AC output voltage for the test of high
voltagecablesandothercapacitiveloads.
Standard features of theVLF Series of AC Hipots
Sine waveoutput, 0.1,0.05 and0.02 Hzfrequencies standard.
Continuouslyadjustableoutput voltage
Continuousdutyrating
Fixedthermalcircuit breakeroverload
“ZeroStart”and External Interlockprovision
Single-rangevoltmeter
Single-rangeCurrent/Capacitancemeter
Twopieceportabledesign
Transitprotectedmeter prevents damagebetweentest sites
Groundstickprovidedforincreasedoperatorsafety. Can be used to safelyconnecttheunitandthetest load to ground
beforeandaftertest
Internaloutputlimit resistor
12ft.inputline cord
SECTION
1
OPERATOR MANUAL
- 3 -
10ft.interconnectcablewithgrounds
20ft.shieldedX-Ray outputcable
Hooktypeoutputconnector
Alligatorcliptypeoutput connector
WARNING
DO NOT OPERATE THE VLF HIPOT SET IF THE HIGH VOLTAGE TANK IS 5OR
MORE FROM LEVEL.
IF THE UNIT IS OPERATED OUT OF LEVEL, OVERHEATING AND INTERNAL ARCING MAY OCCUR.
DONOTSTORE OR TRANSPORTVLFHIGHVOLTAGESECTION
ONIT’SSIDE
OPERATOR MANUAL
- 4 -
Operating Environment
Indoor/Outdoor-fair weather
Altitude: 100% of rating;Sea-level, up to 5000ft.(approx.1500M). The output
power is de-rated 10% above 5000 ft. altitude, 20% above 12,000 ft.( approx.
3600M), and 30% above 15,000 ft.(approx. 4500M)
Storage Temperature: -20C to 70C(-4F to 158F)
Operating Temperature: -5C to 45C(22F to 113F) Output power is de-
rated linearly by 15% from 30 to 45C ambient.
Maximum Relative Humidity: 80% up to 31C(88F), decreasing linearly to
50% at 40C(104F)
Mains supply fluctuation: +/-10% of rated voltage
Installation: Category II
Pollution: Degree 2
WARNING
DO NOT OPERATE THE VLF HIPOT SET IF THE HIGH VOLTAGE TANK IS 5OR
MORE FROM LEVEL.
IF THE UNIT IS OPERATED OUT OF LEVEL, OVERHEATING AND INTERNAL ARCING MAY OCCUR.
DONOTSTORE OR TRANSPORTVLFHIGHVOLTAGESECTION
ONIT’SSIDE
OPERATOR MANUAL
- 5 -
Safety Symbol Identification
Warning! Please refer to documentation before
operation
Protective Earth Terminal
Warning: Hazardous Voltage
OPERATOR MANUAL
- 6 -
Figure2 VLF-90 Seriesfront panel controls
INPUT POWER
The INPUT POWER connector (if applicable) accepts most standard line/extension cords. The
powersuppliedto the input connector must be from a grounded source rated to match the input
powerspecifications.
MAIN POWER
The MAIN POWER pushbutton switch provides the power to the control and power circuits. The
neon lamp in the switch will light when the power is on and voltage is available through input line
cord. The INPUT FUSE located electrically before the MAIN POWER switch provides input line
protectionfortheunit.
EXT.INTLK (EXTERNAL INTERLOCK)
The Ext. Intlk. connector is provided to allow for a normally open safety interlock switch to
control the energizing of thehigh voltage output.
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