METREL GigaOhm 5kV User Manual

GigaOhm 5kV

MI 3202

User Manual

Version 1.4, Code No. 20 751 271

Distributor:

Producer:

METREL d.d.
Ljubljanska 77
SI-1354 Horjul

Tel.: [phone]
Fax: [phone]
E-mail: [e-mail]
http://www.metrel.si

Mark on your equipment certifies that this equipment meets the require ments of the EU
(European Union) concerning safety and electromagnetic compatibility regulations

© 2007, 2010 Metrel
No part of this publication may be reproduced or utilized in any form or by any means

without permission in writing from METREL.

2

MI 3202 GigaOhm 5 kV Table of contents

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 LC Display.....................................................................................................5

2.3 Operator’s Panel ...........................................................................................6

2.4 Connectors.................................................................................................... 7

2.5 Accessories...................................................................................................

2.6 Test leads......................................................................................................

8
8

3 Warnings ............................................................................................................

4 Performing measurements ...............................................................................

4.1 Switching on the instrument ........................................................................

5 Measurements....................................................................................................

5.1 Generally about DC High voltage testing.....................................................

5.2 Guard terminal.............................................................................................

5.3 Insulation Resistance measurement ...........................................................

5.4 Voltage measurement .................................................................................

6 Maintenance.......................................................................................................

6.1 Inspection....................................................................................................

6.2 Insertion and charging batteries for the first time.........................................

6.3 Replacement and charging batteries...........................................................

6.4 Cleaning......................................................................................................

6.5 Calibration...................................................................................................

6.6 Service ........................................................................................................

7 Specifications ....................................................................................................

7.1 Measurements.............................................................................................

7.2 General specifications.................................................................................

10
12

12

14

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15
16
17

19

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22

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3

MI 3202 GigaOhm 5 kV General introduction

1 General introduction

1.1 Features

The GigaOhm 5kV Tester is a portable battery / mains powered test instrument
intended for simple 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 GigaOhm 5kV Tester:

 High Insulation Resistance measurement up to 1 T
 Programmable test voltage: 250 V, 500 V, 1 kV, 2.5 kV, 5 kV;
 Automatic discharge of tested object after measurement completion;
 Voltage and frequency measurement up to 600 V AC/DC.

A segment 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.

1.2 Applied Standards

Instrument operation IEC / EN 61557-2
Electromagnetic compatibility (EMC) EN 61326 Class B
Safety EN 61010-1 (instrument),

EN 61010-031 (accessories)

4

MI 3202 GigaOhm 5 kV Instrument Description

2 Instrument Description

2.1 Instrument Casing

The instrument is housed in a plastic box that maintains the protection class defined in
the general specifications.

2.2 LC Display

The segment LCD has a backlight and offers easy-to-read results and all shows all
associated parameters. See Fig.1 below.

Fig. 1. LC Display

Legend:

1.......... Battery indicator. It indicates condition of the battery. In battery charging mode

it flashes.

2.......... Hazardous Voltage Warning icon. It indicates that the voltage higher than

70 V may be present at the test terminals!

3..........Analogue display.

4..........Auxiliary digital display.

5..........Auxiliary units. Units for parameters displayed on auxiliary display.

6..........Analogue units. Units for parameters displayed on analogue display.

7..........Bar graph.

8..........Warning icon. Read the User Manual with special care!

9..........Pass or Fail icon.

10........Main units.

11........Main digital display.

12........Test voltage. Menu for selecting the test voltage.

5

MI 3202 GigaOhm 5 kV Instrument Description

2.3 Operator’s Panel

The operator’s panel is shown in Fig. 2 below.

Fig. 2. Front panel

Legend:

1.......... key to switch to Insulation measurement mode and to set limit value.

2..........V key to switch to Voltage measurement mode.

3..........Light key to turn the display backlight ON or OFF.

4..........

..........

5

6..........START/STOP key to start or stop insulation measurement.

7..........ON/OFF key to switch the instrument ON or OFF.

cursor



cursor

4

key to decrease the test voltage parameter
key to increase the test voltage parameter

6

and to select limit value.

and to select limit value

.

MI 3202 GigaOhm 5 kV Instrument Description

2.4 Connectors

The GigaOhm 5 kV Tester contains the following connections:

- Connection of test leads to four banana safety sockets (Fig. 3),

- Mains supply cable connection to the mains socket (Fig. 4).

Fig. 3. Test leads connector

1..........Negative Insulation Resistance test terminal. (-OUT)

2..........GUARD test terminals intended to lead away potential leakage current while

measuring the Insulation. Both green sockets are connected together inside the
instrument.

3..........Positive Insulation Resistance test terminal (+OUT)

Use original test accessories only!
Max. allowed external voltage between test terminals and ground is 600V!
Max. allowed external voltage between test terminals is 600V!

7

MI 3202 GigaOhm 5 kV Instrument Description

Fig. 4. Mains connector

1..........Mains connector to connect the instrument to the mains supply.

Use original mains supply cable only!

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.

2.6 Test leads

The standard length of test leads is 2m, optional lengths are 8m and 15m. For more
details see attached list for standard configuration and options or contact your
distributor or see the METREL home page: http://www.metrel.si.
All test leads are made of high voltage shielded cable, because shielded cable provides
higher accuracy and immunity to disturbance of measurements that can occur in
industrial environments

8

MI 3202 GigaOhm 5 kV Instrument Description

2.5.1. High voltage shielded test tips with High voltage alligators clips.

Application notes:
These test leads are designed for diagnostic testing of
insulation and also for hand held testing of insulation.

Insulation ratings:

- High voltage banana connector (red, black): 10kV d.c
(basic insulation). See Fig.5.

- High voltage tip (red, black): 10kV d.c (basic insulation).

- Alligator (red, black): 10kV d.c (basic insulation). See

Fig. 5

Fig.6.

- Guard banana connector (green): 600V CAT IV (double
insulation).

- Cable (yellow): 12kV (shielded). See Fig.5.

Fig. 6

2.6.1 Guard test lead with alligator

Insulation ratings:

- Guard test lead with banana connectors (green): 600V CAT IV (double insulation);

- Alligator (green): 600V CAT IV (double insulation).

9

MI 3202 GigaOhm 5 kV Warnings

3 Warnings

In order to reach the highest level of operator’s safety while carrying out various
measurements and tests using the GigaOhm 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 70 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,
 Do not use the instrument and accessories, if any damage is noticed!

 Consider all generally known precautions in order to avoid risk of electric
 Consider all generally known precautions in order to avoid the risk of electric
 Service intervention or recalibration procedure can be carried out only by a
 Only adequately trained and competent persons may operate the instrument.

 A segment LCD offers easy-to-read results and all associated parameters.

the protection provided by the equipment may be impaired!

shock while dealing with hazardous voltages!

shock while dealing with electric installations!

competent and authorized person!

Operation is simple and clear; the operator does not need any special training
(except reading and understanding this Users Manual) to operate the
instrument.

BATTERIES
 Disconnect all test leads, main supply cable and switch the power off before

opening the Battery cover!

 Use only NiMh rechargeable batteries (C size)!

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 DC or

AC (CAT IV environment) to prevent any damage to the test instrument!

10

MI 3202 GigaOhm 5 kV Warnings

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!
 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 9 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 IV

environment).

11

MI 3202 GigaOhm 5 kV Performing measurements

4 Performing measurements

4.1 Switching on the instrument

Auto-calibration
The instrument is switched ON by pressing the ON/OFF key. After turning on (Fig. 7),
the instrument first executes the auto-calibration (Fig. 8).

Note:

If batteries are defective or missing and the instrument is powered from mains supply,
the instrument could not be turn ON

Measuring test leads have to be disconnected during auto-calibration. If not the auto­calibration procedure could be false.
After finishing the auto-calibration, the pass icon will appeared; the instrument goes to
the Insulation Mode (Fig.9) and is prepared for normal operation.

Auto-calibration prevents a reduction in accuracy when measuring very low currents. It
compensates the effects caused by ageing, temperature and humidity changes etc.
A new auto-calibration is recommended when the temperature changes by more than
5C.

Fig. 7. First introduction Fig. 8. Auto-calibration state

Note:

If the instrument detects incorrect an state during the auto-calibration, the fail icon x

will be displayed:
Possible reasons for out of range conditions are excessive humidity, excessively high
temperature, etc. In this case it is possible to perform measurements by press
START/STOP button again but results could be out of technical specification.

Mains powered instrument operation

If you connect the instrument to the mains supply when the instrument is turned OFF,
internal charger will begin to charge the batteries but instrument will be remain turned
OFF. In upper left angle of LCD, flashing battery indicator will appear to indicate that the
batteries are charging.

Fig. 9. Insulation Mode

12

MI 3202 GigaOhm 5 kV Performing measurements

Note: If batteries are defective or missing, the charger will not work.
If you connect the instrument to the mains supply when instrument is turn ON, the

instrument will automatically switch from the battery supply to the main supply. If the
instrument is not in insulation measuring mode*, internal charger will begin to charge
the batteries. In upper left angle of LCD, battery indicator will start to flash, indicating
that the batteries are charging.

Note: It is not recommended to connect or disconnect the instrument to mains supply
while the instrument is in measuring mode*.

*measuring mode When the instrument performing insulation measurements.

Backlight operation (battery powered instrument)

After turning the instrument ON the LCD backlight is automatically turned ON. It can be
turned OFF and ON by simply clicking the LIGHT key.

Backlight operation (mains powered instrument)

After turning the instrument ON the LCD backlight is automatically turned OFF. It can be
turned OFF and ON by simply clicking the LIGHT key.

Off function

The instrument can be switched OFF only by pressing the ON/OFF key. The auto-off
function is not available to allow long-term measurements.

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MI 3202 GigaOhm 5 kV Measurements

5 Measurements

5.1 Generally about DC High voltage testing

The purpose of insulation tests

Insulating materials are important parts of almost every electrical product. The
material’s properties depend not only on its compound characteristics but also on
temperature, pollution, moisture, ageing, electrical and mechanical stress, etc. Safety
and operational reliability require the regular maintenance and testing of the insulation
material to ensure it is kept in good operational condition. High voltage tests are used to
test insulating materials.

DC vs. AC testing voltage

Testing with a DC voltage is widely accepted as being as useful as testing with AC and /
or pulsed voltages. DC voltages can be used for breakdown tests especially where high
capacitive leakage currents interfere with measurements using AC or pulsed voltages.
DC is mostly used for insulation resistance measurement tests. In this type of test, the
voltage is defined by the appropriate product application group. This test voltage is
lower than the voltage used in the withstanding voltage test so the tests can be applied
more frequently without stressing the test material.

Electrical representation of insulating material

The following figure (Fig.10) represents the equivalent electrical circuit of insulating
material

surface

Itest

+

material

Riss1

Cpi

Guard

Riso

Rpi

Ciso

Riss2

-

Fig. 10

R

and R

iss1

R

– the actual insulation resistance of material

iso

C

– capacitance of material

iso

Cpi, Rpi - represents polarization effects.
The right figure shows typical currents for that circuit.
I

= overall test current (I

test

I

= polarization absorption current

PI

I

= actual insulation current

RISO

I

= surface leakage current

RISS

- the surface resistivity (position of optional guard connection)

iss2

= IPI+ I

test

RISO

+ I

RISS

)

Itest

I

PI

I

Ciso

I

Riso

I

Riss

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MI 3202 GigaOhm 5 kV Measurements

A

A

5.2 Guard terminal

The purpose of the GUARD terminal is to lead away potential leakage currents (e.g.
surface currents), which are not a result of the measured insulation material itself but
are a result of surface contamination and moisture. This current interferes with the
measurement i.e. the Insulation Resistance result is influenced by this current. The
GUARD terminal is internally connected to the same potential as the negative test
terminal (black one). The GUARDs test clip should be connected to the test object so as
to collect most of the unwanted leakage current, see the Fig. 11 below.

I

L

I

M

I

L

I

+OUT +OUT

-OUT

A

I

M

I

A

I

-OUT GUARD

L

Ut Ut

Fig. 11. Connection of GUARD terminal to measured object

where:

Ut........Test voltage

IL.........Leakage current (resulted by surface dirt and moisture)

IM ........ Material current (resulted by material conditions)

IA.........A-meter current

Result without using GUARD terminal: RINS = Ut / IA = Ut / (IM + IL) …incorrect result.
Result using GUARD terminal: R

INS = Ut / IA = Ut / IM ……correct result.

It is recommended to use the GUARD connection when high insulation resistance
(>10G ) are measured.

Note:

 The guard terminal is protected by an internal impedance (200 K).
 The instrument has two guard terminals to allow easy connection of shielded

measuring leads.

15

MI 3202 GigaOhm 5 kV Measurements

5.3 Insulation Resistance measurement

Select this function by pressing the  key displays the following states (initial state and
state with results after the completion of the measurement). See Fig. 12 below.

Initial display

Display with results

Fig. 12. Insulation Resistance function display states

Legend of displayed symbols in Fig 12:

INSULATION RESISTANCE

250V
253 V

102 M
Bar

Name of selected function
Selected test voltage
Actual test voltage (measured value)
Insulation Resistance – result

Analog presentation of result

Measurement procedure:

- Connect the test leads to the instrument and to the test object.

- Select INSULATION RESISTANCE mode by pressing the  key.

- Press the START/STOP key and release it, (continuous measurement will begin).

- Wait until the test result has stabilized then press the START/STOP key again to
stop the measurement.

- Wait for the object under test until it is discharged.

Notes:

- A high-voltage warning symbol appears on the display during the measurement to

warn the operator of a potentially dangerous test voltage.

16

MI 3202 GigaOhm 5 kV Measurements

Set-up test voltage for Insulation
Resistance (Fig.13):
Adjust test voltage using the  and 
keys.

Fig. 13. Set-up test voltage in Insulation

Resistance measurement

Legend of displayed symbols:

INSULATION RESISTANCE

Unominal 250V

Name of selected function
Set test voltage

Set-up Insulation resistance limit
value for Insulation Resistance (Fig.13):

- Press the key ,

- Adjust the limit value using the

keys and ,

- Press the key  again or the key
START to return to into insulation
resistance measurement menu.

Fig. 13a. Set-up Insulation Resistance limit

value

Legend of displayed symbols:

INSULATION RESISTANCE

Resistance value

1 M

Name of selected function
Selected insulation resistance limit

Insulation resistance limit selection range: [10 k .. 200 M]
No limit selected indication: – – –

Warning!

 Refer to Warnings chapter for safety precautions!

5.4 Voltage measurement

Select this function by pressing the V key. Voltage measurement is active immediately
after entering the function. See Fig. 14 below.

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MI 3202 GigaOhm 5 kV Measurements

Fig. 14. Voltage function display

Measurement procedure:

- Connect the test leads to the instrument and to the measured source.

- Press the V key to select voltage mode, continuous measurement will automatically

start to run.

Warning!

 Refer to Warnings chapter for safety precautions!

18

MI 3202 GigaOhm 5 kV Maintenance

6 Maintenance

6.1 Inspection

To maintain the operator’s safety and to ensure the reliability of the instrument it is
advisable to inspect the instrument on a regular basis. Check that the instrument and its
accessories are not damaged. If any defect is found please consult your service center,
distributor or manufacturer.

6.2 Insertion and charging batteries for the first time

Battery cells are stored in the bottom section of the instrument casing under the battery
cover (see Fig. 15). When inserting batteries for the first time please note the following:

 Disconnect any measurement accessories or mains supply cable connected to

the instrument before opening the battery cover to avoid electric shock.

 Remove the battery cover.
 Insert batteries correctly (see Fig. 15), otherwise the test instrument will not

operate!

 Replace the battery cover and fixed the cover back in place.

Connect the instrument to the mains power supply for 14 hours to fully charge batteries.
(Typical charging current is 300 mA).
When you charge the batteries for the first time, it normally takes about 3 charge and
discharge cycles for the batteries to regain full capacity.

6.3 Replacement and charging batteries

The instrument is designed to be power by rechargeable battery supported by mains
supply. The LCD contains an indication of battery condition (upper left section of LCD).
When the low-battery indication appears (Err) the batteries have to be recharged,
connect the instrument to the mains power supply for 14 hours to recharge cells. Typical
charging current is 300 mA.

Note:

 Operator does not need to disconnect the instrument from mains supply after the full

recharging period. The instrument can be connected permanently.

Fully charged rechargeable batteries can supply the instrument for approx. 4 hours.
(Continues testing at 5kV)
If the batteries have been stored for a long time, it normally takes about 3 charge and
discharge cycles for the batteries to regain full capacity.
Battery cells are stored in the bottom section of the instrument casing under the battery
cover (see Fig. 15). In case of defective batteries please note the following:

19

MI 3202 GigaOhm 5 kV Maintenance

 Turn the power off and disconnect any measurement accessories or mains

supply cable connected to the instrument before opening the battery cover to
avoid electric shock.

 Remove the battery cover.
 All six cells have to be replaced and they have to be of the same type.
 Insert the batteries correctly (see Fig. 15), otherwise the test instrument will

not operate and the batteries may be discharged!

 Replace the battery cover and fixed the cover back in place.
 The Instrument will only work when rechargeable batteries are inside the

instrument.

Nominal power supply voltage is 7.2 V DC. Use six NiMH cells with C size (dimensions:
diameter = 26 mm, height = 46 mm). See the next figure Fig.15 for correct polarity of
batteries.

Fig. 15. Correct inserted batteries

1..........Battery cover.

2..........Screw (unscrew to replace the batteries).

3..........Correct inserted batteries.

Ensure batteries are used and disposed of in accordance with Manufacturers guidelines
and in accordance with Local and National Authority guidelines

DISCONNECT ALL TEST LEADS AND SWITCH OFF INSTRUMENT
BEFORE REMOVING THE BATTERY COVER!
HAZARDUS VOLTAGE!

20

MI 3202 GigaOhm 5 kV Maintenance

6.4 Cleaning

Use a soft cloth, slightly moistened with soapy water or spirit to clean the surface of the
instrument and leave the instrument to dry totally before using it.

Notes!

 Do not use liquids based on petrol or hydrocarbons!
 Do not spill cleaning liquid over the instrument!

6.5 Calibration

It is essential that all measurement instruments be regularly calibrated. For occasional
daily use we recommend an annual calibration to be carried out. When the instrument is
used continuously every day, we recommend calibrating the instrument every six
months.

6.6 Service

For repairing under or out of warranty period contact your distributor for further
information.

21

MI 3202 GigaOhm 5 kV Specifications

7 Specifications

7.1 Measurements

Note: All data regarding accuracy are given for nominal (reference) environment
condition.

Insulation resistance

Nominal test voltage: 250 V, 500 V, 1 kV, 2.5 kV, 5 kV
Current capability of test generator: >1 mA
Short-circuit test current: 5 mA.
Automatic discharge of tested object: yes

Measuring range Riso: 0.12 M up to 999 G*

Display range Riso Resolution Accuracy

5 999 k 1 k

1.00  9.99 M 10 k

10.0  99.9 M 100 k
100  999 M 1 M

1.00  9.99 G 10 M

10.0  99.9 G 100 M
100  999 G 1 G (10 % of reading + 3 digits)

*

Full-scale value of insulation resistance is defined according the following equation:

RFS = 1G * U

[V] (if U

test

> 1kV then RFS = 1T

test

For insulation resistance value under 5 kthe instrument displays value 0 

)

(5 % of reading + 3 digits)

DC test voltage:
Voltage value: 250V, 500V, 1kV, 2,5kV, 5kV.
Accuracy: -0 / +10 % + 20 V.
Output power: 5 W max.

Display range test voltage (V) Resolution Accuracy

0  1999V

2.00k  5.50k

1 V

10 V

(3 % of reading + 3 V)

22

MI 3202 GigaOhm 5 kV Specifications

Generator Capability vs Resistance

6

5

4

3

[ kV ]

2

1

0

0,1 1 10 100

[ M ]

Utest=5kV

Voltage

Voltage AC or DC

Display range External Voltage (V) Resolution Accuracy

0  600

1 V

(3 % of reading + 4 V)

Frequency of external voltage

Display range (Hz) Resolution Accuracy

0 and 45  65

0.1 Hz

0.2 Hz

Note:

- for frequency between 0 and 45 Hz frequency result is shown as _ _ _

- for frequency over 65 Hz frequency result is shown as _ _ _

- for voltages under 10V frequency result is shown as _ _ _

Input resistance: 3 M  10 %

23

MI 3202 GigaOhm 5 kV Specifications

7.2 General specifications

Battery power supply.....................................7.2 V DC (6 × 1.2 V NiMHC size)

Mains power supply.......................................90-260 V AC, 45-65 Hz, 40 VA

Over-voltage category ...................................300 V CAT III

Protection classification.................................double insulation

Measurement category.................................. 600 V CAT IV

Pollution degree.............................................2

Degree of protection......................................IP 40 with case closed

Dimensions (w × h × d).................................. 31 cm x 13 cm x 25 cm

Weight (without accessories, with batteries).. 3 kg

Visual and sound warnings............................ yes

Display........................................................... LCD segments and analogue scale with

backlight

ENVIRONMENT CONDITIONS

Working temperature range........................... -10  50 °C

Nominal (reference) temperature range......... 10  30 °C

Storage temperature range............................ -20  +70 C.

Maximum humidity ........................................90% RH (0  40 °C) non-condensing

Nominal (reference) humidity range............... 40  60 % RH

Nominal altitude.............................................up to 2000m

AUTO-CALIBRATION

Auto-calibration of measuring system............ every time after turning power on

CONNECTING SYSTEM

Two safety banana sockets........................... +OUT, -OUT (10kV CAT I, Basic)

Two GUARD. banana sockets....................... GUARD (600V CAT IV, Double)

Guard resistance ........................................... 200 k 10 %

DISCHARGING
Every time after measurement completion.

Discharging resistance: .................................300 k  10 %

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