METREL TeraOhm User Manual
TeraOhm 5 kV
MI 2077
User Manual
Version 1.4, Code No. 20 750 722
TeraOhm 5kV
2
Distributor:
Producer:
METREL d.d.
Horjul 188
1354 Horjul
Slovenia
© 2002 Metrel
No part of this publication may be reproduced or utilized in any form or by any means
without permission in writing from METREL.
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Table of contents
1. General introduction--------------------------------------------------------------------------- 4
1.1. Features ----------------------------------------------------------------------------------------4
1.2. Applied Standards----------------------------------------------------------------------------4
2. Instrument Description ----------------------------------------------------------------------- 5
2.1. Instrument Casing----------------------------------------------------------------------------5
2.2. Operator’s Panel------------------------------------------------------------------------------5
2.3. Connectors -------------------------------------------------------------------------------------6
2.4. Bottom Section--------------------------------------------------------------------------------7
2.5. Accessories ------------------------------------------------------------------------------------7
3. Warnings------------------------------------------------------------------------------------------- 8
4. Performing measurements ------------------------------------------------------------------ 10
4. 1. Switching on the instrument --------------------------------------------------------------10
4.2. Configuration ----------------------------------------------------------------------------------11
5. Measurements ----------------------------------------------------------------------------------- 12
5.1. Generally about DC High voltage testing ----------------------------------------------12
5.2. Guard terminal --------------------------------------------------------------------------------15
5.3. Filter option-------------------------------------------------------------------------------------16
5.4. Voltage measurement-----------------------------------------------------------------------18
5.5. Insulation Resistance measurement ----------------------------------------------------18
5.6. Diagnostic test --------------------------------------------------------------------------------20
5.7. Step Voltage Insulation Resistance testing--------------------------------------------23
5.8. Withstanding voltage ------------------------------------------------------------------------25
6. Operation with Results ----------------------------------------------------------------------- 28
6.1. Store, Recall and Clear Operation -------------------------------------------------------28
6.2. Data transfer -----------------------------------------------------------------------------------30
7. Maintenance -------------------------------------------------------------------------------------- 31
7.1. Inspection---------------------------------------------------------------------------------------31
7.2. Battery Replacement ------------------------------------------------------------------------31
7.3. Cleaning ----------------------------------------------------------------------------------------32
7.4. Calibration --------------------------------------------------------------------------------------32
7.5. Service ------------------------------------------------------------------------------------------32
8. Specifications------------------------------------------------------------------------------------ 33
8.1. Measurements --------------------------------------------------------------------------------33
8.2. General specifications-----------------------------------------------------------------------35
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1. General introduction
1.1. Features
The TeraOhm 5kV Tester is a portable battery / mains powered test instrument intended
for testing of Insulation Resistance by using high test voltages of up to 5 kV. It operates
on a SIMPLE and CLEAR basis.
The instrument is designed and produced with the extensive knowledge and experience
acquired through many years of dealing with similar test equipment.
Available functions offered by the TeraOhm 5kV Tester:
• High Insulation Resistance measurement up to 5 TΩ
- Programmable test voltage 250 V up to 5 kV
- Programmable timer 1s up to 30 min
- Automatic discharge of tested object after measurement completion
- Capacitance measurement
• Insulation Resistance measurement versus test voltage (step-up voltage)
- Five discrete test voltages proportionately set within preset test voltage range
- Programmable timer 1min up to 30 min per step
• Polarization Index PI and Dielectric Discharge ratio
- PI = RINS (t2) / RINS (t1)
- DD = Idis (1min) / C⋅U
• Withstanding voltage (DC) up to 5.5 kV
- Programmable ramp test voltage 250 V up to 5 kV
- High resolution ramp (approx. 20 V per step)
- Programmable threshold current
• Voltage and frequency measurement up to 600 V AC/DC
A dot matrix LCD offers easy-to-read results and all associated parameters. Operation is
simple and clear; the operator does not need any special training (except reading and
understanding this Users Manual) to operate the instrument.
The instrument allows storage of test results. Professional PC SW enables simple
transfer of test results and other parameters in both directions between the test
instrument and PC.
1.2. Applied Standards
Instrument operation IEC / EN 61557-2
Electromagnetic compatibility (EMC) IEC 61326 Class B
Safety EN 61010-1 (instrument),
EN 61010-31 (accessories)
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2. Instrument Description
2.1. Instrument Casing
The instrument is housed in a plastic casing that maintains the protection class defined
in the general specifications. The casing is equipped with a carrying strap, which is
intended for the instrument to be used hung around the operator’s neck. Short technical
specification is available on base of the housing.
2.2. Operator’s Panel
The operator’s panel consists of a dot matrix LCD, a rotary switch, and a keypad; see
the figure below.
Fig. 1. Front panel
Legend:
1 ..........START key to start any measurement.
2 ..........ON/OFF key to switch the instrument ON or OFF.
3 ..........MEM key to store, recall and erase results.
4 ..........SELECT key to enter set-up mode for the selected function or to select the
active parameter to be set.
5 ..........
5
cursor key to select an option upward.
6 ..........
6
cursor key to select an option downward.
7 ..........
3
cursor key to decrease the selected parameter.
8 ..........
4
cursor key to increase the selected parameter.
9 ..........ESC key to exit the selected mode.
10 ........Light key to turn the display backlight ON or OFF.
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2.3. Connectors
The TeraOhm 5 kV Tester contains the following connections:
- Connection of test leads to three banana safety sockets (1, 2, 3),
- Connection of the communication cable to the 9-pin RS 232 connector (4) and
- Mains supply cable connection to the mains socket (5).
Fig. 2. Connectors
Legend:
1 ..........Positive Insulation Resistance test terminal.
2 ..........Negative Insulation Resistance test terminal.
3 ..........GUARD test terminal intended to lead away potential leakage current while
measuring the Insulation Resistance.
4 ..........Galvanic separated RS 232 connector to connect the instrument to PC.
5 ..........Mains connector to connect the instrument to the mains supply.
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2.4. Bottom Section
The bottom assembly is presented in the figure below. The carrying strap is fixed to the
bottom section by means of a plastic cover (2).
6
5
7
4
2
1
3
DISCONNECT ALL TEST LEADS AND SWITCH OFF INSTRUMENT,
BEFORE REMOVING THIS BATTERY/FUSE COVER - HAZARDOUS VOLTAGE!
DO NOT CHARGE IF BATTERY COMPARTMENT CONTAINS ALKALINE CELLS!
POWER SUPPLY: 6×1.2V - NiCd, NiMH RECHARGEABLE (IEC LR 14)
or 6×1.5V - ALKALINE BATTERIES (IEC LR 14)
VOR OFNEN DES BATTERIEFACHS ALLE ZULEITUNGEN VOM GERAT
ENTFERNEN UND DAS GERAT AUSSCHALTEN - GEFAHRLICHE SPANNUNG!
NICHT AUFLADEN WENN ALKALZELLEN VERWENDET SIND!
STROMVERSORGUNG: 6×1.2V - (IEC LR 14)
oder
NiCd, NiMH AUFLADBAR
6×1.5V - ALKALZELLEN (IEC LR 14)
Fig. 3. Bottom section
Legend:
1 .......... Nylon strap (allows the operator to carry the instrument hung around the neck).
2 ..........Plastic cover (fixes the nylon strap to the instrument).
3 .......... Screw (unscrew to remove the carrying strap or to open the instrument).
4 .......... Label with measurement ranges.
5 ..........Battery/fuse compartment cover.
6 ..........Screw (unscrew to replace the batteries).
7 ..........Rubber foot.
2.5. Accessories
The accessories consist of standard and optional accessories. Optional accessories can
be delivered upon request. See attached list for standard configuration and options or
contact your distributor or see the METREL home page: http://www.metrel.si .
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3. Warnings
In order to reach the highest level of operator’s safety while carrying out various
measurements and tests using the TeraOhm 5kV Tester, as well as to ensure that the
test equipment remains undamaged, it is necessary to consider the following warnings:
MEANING OF SYMBOLS
♦
!
symbol on the instrument means “Read the User Manual with special care!”
♦
symbol on the instrument means “Hazardous voltage higher than 1000 V
may be present at the test terminals!”!
GENERAL PRECAUTIONS
♦ If the test equipment is used in a manner not specified in this Users Manual,
the protection provided by the equipment may be impaired!
♦ Do not use the instrument and accessories, if any damage is noticed!
♦ Consider all generally known precautions in order to avoid the risk of electric
shock while dealing with electric installations!
♦ Service intervention or recalibration procedure can be carried out only by a
competent and authorized person!
♦ Only adequately trained and competent persons may operate the instrument.
BATTERIES
♦
Disconnect all test leads and switch the power off before opening the Battery
cover!
♦ Avoid connection to main supply when alkaline batteries are inserted, danger
of explosion! Do not charge when alkaline batteries are fitted!
EXTERNAL VOLTAGES
♦ Do not connect the instrument to a mains voltage different from the one
defined on the label adjacent to the mains connector, otherwise the instrument
may be damaged.
• Do not connect test terminals to an external voltage higher than 600 V AC or
DC (CAT III environment) to prevent any damage on the test instrument!
WORKING WITH THE INSTRUMENT
♦ Use only standard or optional test accessories supplied by your distributor!
♦ Equipment under test must be switched off i.e. de-energized before test leads
are connected to the equipment.
♦ Do not touch any conductive parts of equipment under test during the test.
♦ Make sure that the tested object is disconnected (mains voltage disconnected)
before starting the Insulation Resistance measurement!
• Do not touch the tested object whilst testing it, risk of electric shock!
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• In case of a capacitive test object (long tested cable etc.), automatic discharge
of the object may not be done immediately after finishing the measurement –
“Please wait, discharging” message will be displayed.
HANDLING WITH CAPACITIVE LOADS
♦ Note that 40 nF charged to 1 kV or 1.6 nF charged to 5 kV are hazardous live!
♦ Never touch the measured object during the testing until it is totally
discharged.
♦ Maximum external voltage between any two leads is 600 V (CAT III
environment).
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4. Performing measurements
4. 1. Switching on the instrument
Autocalibration
The instrument is switched ON by pressing the ON/OFF key. After turning on, the
instrument first executes the autocalibration (Fig. 5).
It is necessary that the measuring test leads are disconnected during autocalibration. If
not the instrument will require disconnection of the test leads and repeat switching OFF
and ON.
After finishing the autocalibration, the instrument is prepared for normal operation.
Autocalibration prevents lowering of the accuracy when measuring very low currents. It
compensates the effects caused by ageing, temperature and humidity changes etc.
A new autocalibration is recommended when the temperature changes by more than
5°C.
Fig. 4. First introduction
Fig. 5. Auto-calibration state
Note:
If the instrument detects incorrect state during the autocalibration, the following warning
message will be displayed:
ERROR!
-TEST LEADS CONNECTED:
DISCONNECT AND SWITCH ON THE INSTRUMENT AGAIN
- CONDITIONS OUT OF RANGE: PRESS START TO CONTINUE
Possible reasons for out of range conditions are excessive humidity, too high
temperature, etc. In this case it is possible to perform measurements but results could
be out of technical specification.
Backlight operation
After turning the power on the LCD backlight is automatically turned on. It can be turned
OFF and ON by simply clicking the LIGHT key.
Backlight turns off automatically approximately 10s after switching it ON, if the
instrument is supplied by the internal battery.
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Off function
The instrument can be switched OFF only by pressing the ON/OFF key. The auto-off
function is not available due to the possible long-term measurements.
4.2. Configuration
The configuration function enables the selection and adjustment of the parameters that
are not directly involved in the measurement procedure (Figure 6).
In the lower section of the display the supply status, date and time is shown (same in all
functions).
The following procedure must be carried out when adjusting some of the configuration
parameters:
1. Use
↑↑↑↑
and
↓↓↓↓
arrows to select parameter (line) to be adjusted.
2. Use
←←←←
and
→→→→
arrows to change the value of the selected parameter. If there are two
or more sub-parameters in one line (e.g. date and time) then use the SELECT key to
skip to the next sub-parameters and back.
To clear all memory locations:
1. Select Memory Clear line using the
↑↑↑↑
and
↓↓↓↓
arrows.
2. Press the SELECT key, “Press MEM to confirm!” message will be displayed.
3. Press the MEM key to clear all memory locations or ESC to cancel the activity.
Selected function
Battery status
Mains supply
Date
Time
Function dependent
area
indicator
Fig. 6. Configuration state
Parameter Value Note
Contrast
0%..100% Adjustment of the LCD contrast
Filter
Fil1, Fil2, Fil3, Off Selection of noise rejecting filter, see
chapter 5., Filter Option
Time
Set time (hour: minute)
Date
Set current date (day-month-year)
Baud rate
2400, 4800, 9600, 19200 Speed of data transfer in
communication mode
Memory clear
Clear all memory locations
Initialization
For internal factory and service only!
Table 1. Configuration parameters
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