Megger BM5200 User manual

M
BM5200
5 kV Digital Insulation Tester
USER MANUAL

CONTENTS
Safety warnings ...................................................................................................................................................................................................3
Symbols used on instrument .............................................................................................................................................................................4
Cleaning .......................................................................................................................................................................................................4
General description ............................................................................................................................................................................................5
Insulation resistance test modes ................................................................................................................................................................5
Automatic discharge ....................................................................................................................................................................................5
Lead set ........................................................................................................................................................................................................5
Instrument power .......................................................................................................................................................................................5
Instrument safety ........................................................................................................................................................................................5
Preparations for use ............................................................................................................................................................................................6
Operating instructions........................................................................................................................................................................................7
Instrument controls and indicators ...........................................................................................................................................................7
Use of guard terminal (G) ..........................................................................................................................................................................8
Polarisation index (PI) .................................................................................................................................................................................9
Timed insulation resistance ........................................................................................................................................................................9
Preventative maintenance ..................................................................................................................................................................................9
Battery replacement ....................................................................................................................................................................................9
Technical specifications ....................................................................................................................................................................................10
Repair and warranty ..........................................................................................................................................................................................11
MANUAL DEL USUARIO ...................................................................................................................................................................................13
MANUAL DO UTILIZADOR ..............................................................................................................................................................................24
2

G SAFETY WARNINGS
Safety warning must be observed during use:
n The circuit under test must be switched off, deenergised, isolated and checked to be safe before insulation test connections are made. Make
sure the circuit is not reenergised whilst the instrument is connected.
n Circuit connections must not be touched during an insulation test.
n After completing a test, capacitive circuits must be completely discharged before disconnecting the test leads. Capacitive charges can be
lethal.
n Tested items should be firmly shorted out with a shorting link, after discharge, until required for use. This is to guard against any stored
dielectric absorption charge subsequently being released thereby raising the voltage to potentially dangerous levels.
n The voltage indicator and automatic discharge features should be regarded as additional safety features and not a substitute for normal safe
working practice.
n It is rare, but in certain circumstances, breakdown of the circuit under test may cause the instrument to terminate the test in an uncontrolled
manner, possibly causing a loss of display while the circuit remains energised. In this event, the unit must be turned off and the circuit
discharged manually.
n Test leads, including crocodile clips, must be in good order, clean and with no broken or cracked insulation.
n The instrument should not be used if any part of it is damaged.
n Insulation testing in wet weather conditions might be hazardous. It is recommended that this instrument is not used in these circumstances.
If this is unavoidable, the user must take all necessary precautions.
n This instrument is not intrinsically safe and must not be used in hazardous atmospheres.
n If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.
n Rechargeable batteries should not be used on this instrument.
NOTE
THE INSTRUMENT MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS.
Users of this equipment and/or their employers are reminded that National Health and Safety Legislation requires them to carry out valid risk
assessments of all electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as inadvertent short
circuits. Where the assessments show that the risk is significant then the use of fused test leads may be appropriate.
3

Symbols used on this instrument
G Caution: refer to accompanying notes
F Caution: risk of electric shock
t Class II double insulated instrument
Do not dispose of in the waste stream
Equipment complies with current Australian C-Tick directives
Battery
Terms used in this manual
The word must is used to indicate that the instructions following should be followed under all circumstances. Failure to follow these
instructions could result in damage to the instrument and / or a hazard to the operator.
The word ‘should’ is used to indicate that the instructions indicate best practice.
Cleaning
Disconnect the instrument and wipe it with a clean cloth slightly damped with soapy water or Isopropyl alcohol (IPA).
4
+

General description
BM5200 insulation tester has a digital and analogue arc display
designed for high voltage insulation resistance testing in the
maintenance and servicing of cables, rotating plant machinery,
transformers, switchgear and industrial installations.
DC insulation tests are performed at 250 V, 500 V, 1000 V, 2500 V
and 5000 V. Insulation resistance measuring range is 100 kΩ to
1000 GΩ. Automatic discharge for capacitive circuits under test is
provided and decaying voltage displayed.
The guard terminal can be used to minimise the effects of surface
leakage and hence erroneous measurements when carrying out
insulation resistance tests.
Insulation resistance test modes
Three insulation resistance (IR) test modes are provided, (InS, PI,
t) and selected from any insulation range by pressing the left arrow
key depicting PI-t.
In insulation resistance test mode (InS) tests are initiated by pressing
and holding down the TEST button for two seconds. Once an
insulation test has initiated it will terminate on the next press
of the TEST button. The reading is held on screen until TEST is
pressed again or another range is selected.
A Polarisation Index (PI) mode performs a ratiometric test that
calculates the ratio of insulation resistance at ten minutes to
insulation resistance at one minute.
The timer (t) mode facilitates a single fixed duration IR test based
on the set time interval t.
Automatic discharge
For capacitive test objects the instrument will automatically dis-
charge through an internal resistor and indicate voltage across the
terminals in the range 25 V to 600 V with higher voltages indicated
by ‘>600 V’. This feature will give decaying voltage indication
following the testing of equipment possessing capacitance. When
the voltage indicator no longer shows it is safe for the user to
disconnect the test leads.
Lead set
Three recessed sockets are provided, and marked ‘+’, ‘-’ and ‘G’.
These have safety covers which open when the plugs are inserted.
When inserted into the sockets, the shrouded test lead plugs lock
into position. They are released by twisting the plug a quarter turn
and pulling out.
For this reason, only the test leads supplied or suitable Megger
replacement ones should be used.
Instrument power
The BM5200 is powered by eight 1.5 V IEC LR6/AA alkaline cells.
Rechargeable batteries should not be used on this instrument.
Instrument safety
Design safety features include:
n External voltage indication, AC or DC displayed.
n Load automatically discharged at the end of a test, and decaying
voltage displayed.
n Test leads can lock into the case to prevent accidental disconnection.
5

Preparations for use
1. Unpack the shipping box and locate the BM5200 instrument,
carry case, test leads, batteries, quick start and user guides.
2. Ensure that the main range switch is in the OFF position.
3. Locate the battery compartment and open it using a PZ2
pozidrive screwdriver.
4. Remove the battery module and insert the eight 1.5 VLR6/AA
alkaline cells ensuring correct orientation according to polarity.
5. Connect the battery module to the battery lead ensuring
correct polarity.
6. Replace battery module and battery cover into the case and
replace the two screws tightening by hand only.
7. As an initial check, without any leads connected, switch
the instrument on by turning the main range switch to any
position other than OFF. Ensure that the instrument display
responds. Switch off the instrument. If the instrument display
does not respond return t to step 2, repeat the process
and check all eight battery orientations are correct.
8. If the instrument still fails to respond use a voltmeter to check
battery module voltage which should be 12 V assuming all cells
are at their rated 1.5 V.
6

The BM5200 is turned on by rotating the main range switch to
insulation test, voltage test or setup function.
The rear panel indicates polarity of test sockets and -, + and G
(Guard). The negative (-) terminal is at 0 V and positive (+)
terminal is at test voltage (up to 5000 V DC).
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Operating instructions
Instrument controls and indicators
1. Backlit LCD display with analogue arc and dual 3-digit display.
2. Backlight on/off switch
3. Four arrow buttons, PI-t function on left arrow button
4. Main range switch Setup functions plus AC and DC voltmeter
(25 V to 600 V)
5. Main range switch with DC insulation tests at 250 V, 500 V,
1000 V, 2500 V and 5000 V.
6. TEST button to initiate and terminate insulation tests
7. Warning High Voltage (HV) indicator
Before switching on the BM5200 the test leads should be connected
to the instrument.
There are three test terminals marked +, - and G. These terminals
are designed to accept only the test leads supplied. Shutters across
the terminals prevent accidental ingress of dirt and other objects.
Test lead plugs interlock with the shutters and are released by
rotating the test lead plug a quarter turn.
After testing the charge present on the terminals due to internal
capacitance is fully discharged within 10 seconds of completion of
the test. You should be aware that it will take longer to discharge
external reactive loads.

The battery level indicator is
located at the top right of the
display and contains four pairs of
segments depicting charge level.
Battery level indication of 50% of
battery life.
Battery level indication of a flat
battery.
Use of guard terminal (G)
For basic insulation resistance tests where there is little possibility
of surface leakage affecting the measurement, it is not necessary
to use the guard terminal i.e. if the insulator is clean and there are
unlikely to be any adverse current paths. However in cable testing
for example, there may be surface leakage paths across the insula-
tion between the bare cable and the external sheathing due to the
presence of moisture or dirt. To obtain an accurate measurement,
particularly at high testing voltages, a bare wire may be bound
tightly around the insulation and connected via the third test lead
to the guard terminal ‘G’.
As illustrated in the diagram, the guard terminal is at the same
potential as the negative terminal. Since the leakage resistance is
effectively in parallel with the resistance to be measured, the use
of the guard causes the current flowing through surface leakage to
be diverted from the measuring circuit. The instrument there-
fore reads the leakage of the insulator, ignoring leakage across its
surface.
8

Preventative maintenance
No user serviceable parts
There are no user serviceable parts in the BM5200 except for the
batteries.
If an instrument’s protection has been impaired it should not be
used, but sent for repair by suitably trained and qualified personnel.
The protection is likely to be impaired if for example, it shows
visible damage, fails to perform the intended measurements,
has been subjected to prolonged storage under unfavourable
conditions, or has been subjected to severe transport stresses.
Battery replacement
G WARNING
The battery contacts are not isolated from the test leads.
Remove the test leads from the instrument before opening
the battery compartment.
The cells are housed in a battery compartment in the base of the
instrument. To change the cells, use a PZ2 pozidrive screwdriver
to remove the battery cover securing screws and lift off the battery
compartment cover. Observing the correct polarity as marked on
the battery housing, install 8 replacement IEC LR6 (AA) cells.
Replace and secure the battery compartment cover on completion.
9
Polarisation index (PI)
Polarisation Index (PI) test performs a ratio metric test that
calculates the ratio of insulation resistance at ten minutes, IR10 min
to insulation resistance at one minute, IR1min. This test
provides a simple indication of insulation polarisation when
subjected to high voltage DC. A high PI value indicates a high
degree of insulation polarisation and therefore good insulation
condition. Generally the PI value should be two or above.
Polarisation occurs at different rates ranging from minutes to sev-
eral hours which led the IEEE to create a ratiometric PI test. The
IEEE standard 43-2000, “Recommended Practice for Testing Insula-
tion Resistance of Rotating Machinery,” limits the use of PI test on
winding systems to those with IR1min being less than 5000 MΩ.
Timed insulation resistance
The timed IR test is a test that automatically terminates after a user
adjustable time (t). Users can select SETUP on the range switch
and adjust timer (t) using up and down arrow buttons to set the
desired time followed by a single press of the PI-t (left arrow)
button. Default time (t) is set at one minute because IR1min is
frequently referred to in international standards.