Megger WM6 User manual

M
WM6
Wee Megger Tester
User Guide
Guide de l’utilisateur
Gebrauchsanleitung
Guía del usuario

SAFETY WARNINGS
★ The circuit must be de-energized and isolated BEFORE connections are
made for any test.
★ Do not touch the circuit during an insulation test.
★ After insulation tests, capacitive circuits MUST be allowed to discharge
BEFORE disconnecting the test leads.
★ Test leads, including prods and crocodile clips, must be in good order;
clean and having no broken or cracked insulation.
★ Replacement fuses must be of the correct type and rating.
Refer also to page 8 for further explanations and other precautions.
The warnings and precautions must be read and understood before the
instrument is used. They must be observed during use.
2
NOTE
This instrument must only be used by suitably trained and competent persons.

CONTENTS
Safety Warnings 2
General Description 4
Applications 4
Specification 5
Accessories 7
Operation 8
Warning 8
Preliminary checks 8
Fuse replacement 8
Insulation testing 9
Continuity testing 9
Using the Insulation Tester 10
Preventive maintenance 10
Insulation Testing concepts 11
Mode d’Emploi 12
Betriebsanleitung 14
Instrucciones de Uso 16
Setting-up Procedure 18
Repair and Warranty 19
3

GENERAL DESCRIPTION APPLICATIONS
The WM6 MEGGER®Insulation and Continuity Tester
is a completely self contained instrument designed to
give rapid and accurate measurement of insulation
resistance and continuity resistance.
The WM6 uses a low voltage hand-cranked a.c.
brushless generator as the power supply. This
generator is easy to turn and is connected to a
rectifier and d.c. to d.c. converter to provide the test
voltage.
The WM6 uses a moving coil meter with taut band
suspension, white scales on a black scale plate and
an orange ‘dayglow’ pointer. An electronic circuit is
employed to produce a four decade calibrated scale
for insulation resistance measurement from 0 to
200 MΩ.
Two shrouded sockets are provided in the side of the
case for the test leads and a slider switch selects
either insulation or continuity tests (‘MΩ’ or ‘Ω’). The
case is robust, made of ABS plastic, and the
generator handle folds neatly against it when not in
use.
The WM6 is intended for the direct measurement of
insulation resistance and continuity of domestic and
industrial wiring, cables, transformers, motors,
generators, electrical machinery and appliances.
Because the WM6 is self-powered it is suitable for
use during installation and commissioning work as
well as for service and maintenance applications.
Note:— The cover of this instrument has been given
an antistatic treatment which should be
effective for many months. If in the course of
time the cover is found to retain electrostatic
charges, it should be re-treated with a
suitable antistatic solution.
4

SPECIFICATION
WM6
Ranges insulation 0–200 MΩand ∞
continuity 0–100 Ω
Terminal Voltage insulation range <600 V
on Open Circuit (d.c.) continuity range 800 mV approx.
Terminal Voltage at insulation range 500 V + 10% –5%
1 MΩLoad (d.c.)
Terminal Current insulation range 1,3 mA approx.
on Short Circuit continuity range 55 mA approx.
Voltage Stability insulation range <±1%
160 r.p.m. to 240 r.p.m.
Ripple Content at 160 r.p.m. insulation range 500 mV pk-pk approx.
on Open Circuit
Accuracy 1,5 mm (0,060 in) from any marked position on the
scale when measured against standard resistors.
Temperature operating –10 °C to +50 °C
storage –20 °C to +70 °C
Flash Test 2,3 kV a.c. r.m.s.
Voltage Source (d.c.) Brushless a.c. hand-cranked generator with
rectifier and d.c. to d.c. converter.
5

SPECIFICATION
Fuse 1 A 20 x 5 mm ceramic
Dimensions 131 x 98 x 61 mm (51/8x 37/8x 23/8in)
Weight 650 g (1 lb 7 oz)
Terminal Voltage Characteristics
6
WM6
Terminal voltage (volts d.c.)
Resistance under test (MΩ)

SPECIFICATION ACCESSORIES
Illustrations of Typical Scales (full size)
WM6
SUPPLIED WITH THE INSTRUMENT
Test lead set including shrouded crocodile clips
User Guide Part No. 6171-685
Test Record Card (5 supplied) Part No. 6172-111
AVAILABLE AS AN OPTIONAL EXTRA
A ‘test-and-carry’ case with a special
compartment for test leads Part No. 6420-088
Test Lead set red/black Part No. 6220-437
Test Record Card (Pack of Twenty) Part No. 6111-216
7

OPERATION
WARNING
1. The circuit under test must be de-energized and
isolated before insulation or continuity tests are
made.
2. When capacitive circuits have been tested allow a
suitable time to elapse before disconnecting the
test leads, for the circuit to discharge.
3. Instruments used in dusty environments should be
stripped and cleaned periodically.
4. Do not leave the instrument exposed to direct heat
from the sun for long periods.
5. The instrument circuit contains a static sensitive
device. If the instrument casing is opened for any
reason (this will automatically invalidate any
warranty covering the instrument), care must be
exercised in handling the printed circuit board.
This should be done in accordance with DEF
STAN 59-98 and BS 5783 specifications for
handling electrostatic sensitive devices.
Printed circuit boards containing such devices are
identified either by a yellow warning label or by a
yellow legend and a large yellow dot on the p.c.b.
(Initially the dot may not be included.)
PRELIMINARY CHECKS
Inspect the test leads to see that they have good
unbroken insulation. Connect the red and black leads,
terminated with the clips, to the red (+) and black (–)
terminal sockets respectively in the side of the
instrument case. Leave the leads coiled or twisted
together, but ensure that their clips are not touching
anything. Set the slider switch to the ‘MΩ’ position.
Turn the generator handle at approximately 160 r.p.m.
and observe the meter pointer, it should rest over the
‘∞’ (infinity) position on the scale. If it does not the test
leads may be faulty and should be inspected more
closely for damage. Replace them if necessary.
Connect the test lead clips together and turn the
generator handle again, the meter should read zero.
If it indicates infinity or a high resistance value the
leads may be open circuit and should be inspected
further, replace if necessary. Shorting the leads
together and obtaining a zero reading also proves that
the instrument is working.
To check that the fuse in the continuity circuit is intact,
leave the test leads connected together and set the
slider switch to the ‘Ω’ position. Turn the generator
handle again, the reading obtained should be zero (or
very nearly so). If the reading is beyond full scale on
the ‘Ω’ range the fuse has ruptured and should be
replaced.
8

FUSE REPLACEMENT
The fuse is held in a screw-type holder. To change a
fuse, use a screwdriver to release the centre part of
the holder containing the fuse. Replace with a 1 A
20 x 5 mm ceramic fuse part no. 25413-286. An
alternative fuse should not be used as the fuse
resistance will affect the lower continuity readings.
INSULATION TESTING
After connecting the test leads to the instrument and
making the preliminary checks as detailed above, set
the slider switch to ‘MΩ’. With the circuit to be tested
isolated, connect the test leads as follows:—
(a) for insulation tests to earth —
connect the red lead to earth or frame of the
equipment, and the black lead to that part of the
circuit to be tested.
(b) for insulation tests between wires —
connect a lead to the core of each of the wires.
Turn the generator handle at between 160 r.p.m. and
240 r.p.m. The meter pointer will indicate the value of
insulation resistance on the ‘MΩ’ scale. (If a capacitive
circuit is tested the pointer will initially deflect towards
zero and then gradually rise to its final steady value as
the capacitance is charged up to the output voltage of
the tester.)
If several successive readings of ‘∞’ are obtained,
connect the two further ends of the test leads together
and turn the generator handle. A zero reading should
result which double checks that the leads are not
disconnected or broken and therefore the insulation
resistance readings are correct.
Capacitive circuits automatically discharge through
the tester when the generator handle stops rotating.
The meter pointer will deflect beyond the ‘∞’ position
on the scale and then return to its normal rest position
at ‘∞’ when the circuit has discharged. Wait a few
moments for this to happen before disconnecting the
test leads. The discharge time (to 0 V) is approx. 8
seconds per microfarad.
CONTINUITY TESTING
With the test leads connected to the instrument, and
having checked them and the fuse as described
above, set the slider switch to the ‘Ω’ position. With the
circuit under test isolated, connect the test leads
across the appropriate points and turn the generator
handle at between 160 r.p.m. and 240 r.p.m. The
resistance will be indicated on the ‘Ω’ scale. This
resistance includes that of the test leads which should
be measured separately, (by performing a test with
the clips joined together), and the result deducted
from the total.
9

Preventive Maintenance
The proverb ‘A stitch in time saves nine’ inspired the
title of an Megger Limited booklet on insulation
testing, as it neatly sums up the benefits of
preventative maintenance. The savings come in
financial terms from costly repairs, lost production, lost
profits and in human terms, from lives saved in the
event of dangerous electrical faults.
Regular insulation testing of electrical equipment can
help to detect deteriorating insulation. The effects
which cause insulation to deteriorate include
mechanical damage, vibration, excessive heat or cold,
dirt, oil, moisture and localized voltage stresses - all of
which can arise on most industrial or utility equipment.
Insulation tests are sometimes used in isolation as
absolute measures of the quality of the insulation. This
is most appropriate when equipment is being installed
and checked for compliance with a specified ‘Pass’
level. For operational equipment the key factors are
trends in the insulation readings.
It is therefore important that records of insulation
readings are kept, relating to each piece of equipment
or ‘Asset’ in your testing regime. Megger Limited
supplies test record cards to assist with such record
keeping. There are also a number of influences on the
insulation readings - temperature, humidity and
surface leakage for example and a range of test
techniques have been developed to help with the
interpretation of your insulation tests.
10 Test Record Example

Insulation Testing Concepts
Insulation resistance can be considered by applying
Ohm’s Law. The measured resistance is determined from
the applied voltage divided by the resultant current, V
R = I
There are two further important factors to be considered.
These are:
(i) the nature of the current through and/or over the
insulation, and :
(ii) the length of time for which the test voltage is applied.
These two factors are linked.
The total current that flows is made up of three separate
currents:-
1. Capacitance charging current. This current is initially
high and drops as the insulation becomes charged up
to the applied voltage.
2. Absorption current. This current is also initially high
but drops at a much slower rate than the charging
current.
3. Conduction or Leakage current. This is a small
steady current that can be sub-divided into two:-
(a) A current flowing along conduction paths through
the insulation material.
(b) A current flowing along conduction paths over the
surface of the insulation material.
As the total current depends upon the time for which the
voltage is applied, Ohm’s Law theoretically applies at
infinite time.
The charging current falls relatively rapidly as the
equipment under test becomes charged up. The actual
length of time depends upon the size and capacitance of
the item under test.
Larger items with more capacitance will take longer e.g.
long supply cables. The absorption current decreases
relatively slowly compared with the charging current. In
essence it depends upon the nature of the insulation
material. The conduction or Leakage current builds up
quickly to a steady value and then remains constant for a
particular applied voltage under stable conditions. It is this
current that is affected by moisture, dirt etc. and the
degree to which it flows bears a direct relation to the
quality of the insulation, and consequently to the value of
the insulation resistance measured. An increase in the
leakage current is a pointer to possible future problems.
11

MODE D’EMPLOI
AVERTISSEMENTS
1) Le circuit à essayer doit être mis hors tension et
isolé, préalablement à toute mesure.
2) Après l’essai de circuits capacitifs, attendre le
temps nécessaire à la décharge avant de retirer
les cordons de mesure.
3) Les appareils utilisés dans les environnements
poussiéreux doivent être démontés et nettoyés
périodiquement.
4) Ne pas laisser l’appareil trop longtemps exposé au
soleil.
VERIFICATIONS PRELIMINAIRES
Vérifier si l’isolement des cordons de mesure est
correct. Pour ce, brancher les cordons rouge et noir,
munis de leur pince crocodile, dans les bornes rouge
(+) et noire (–) de l’appareil.
Torsader ensemble les deux cordons et s’assurer que
leurs extrémités ne sont pas en contact. Placer le
commutateur de gamme sur “MΩ”. Tourner la
manivelle du générateur à environ 160 tours par
minute et controler que l’aiguille de l’indicateur se
place sur la position “∞” de l’échelle. Si ce n’est pas
le cas, il faut vérifier minutieusement l’état des cordons
et les remplace si nécessaire.
Court-circuiter les pinces crocodiles et actionner à
nouveau la manivelle. L’aiguille de l’indicateur doit se
placer sur le zéro de l’échelle. En cas d’indication de
résistance de valeur élevée (ou position ‘∞’) les
cordons sont peut-être coupés. Vérifier leur état et les
remplacer si nécessaire.
Le fait d’obtenir une lecture ‘zero’ apres avoir court
circuite les cordons d’essai est aussi une preuve de
bon funcionement de l’instrument.
Pour vérifier l’état du fusible du circuit de continuité,
laisser les cordons en court-circuit et placer le
commutateur de gamme sur la position ‘Ω’. Tourner la
manivelle du générateur. On doit obtenir une lecture
très proche de zéro. En cas de lecture ohmique
élevée, le fusible est coupé et doit être remplacé.
REMPLACEMENT DU FUSIBLE
Le fusible est placé dans un logement fixé entre les
bvornes de sortie de l’appareil. Pour remplacer un
fusible, dévisser à l’aide d’un tournevis la partie
centrale du logement porte-fusible. Utiliser des
fusibles ceramique 1 A (20 x 5 mm).
MESURE D’ISOLEMENT
Après avoir branché les cordons sur l’appareil et avoir
réalisé les essais préliminaires indiqueés ci-dessus,
placer le commutateur de gamme sur ‘MΩ’. Une fois le
circuit à tester isolé, brancher les cordons comme suit:
12

(a) Pour les essais d’isolement par rapport à la terre
— Relier le cordon rouge à la terre ou au bâti de la
structure en essai, et le cordon noir à la partie du
circuit à mesurer.
(b) Pour les essais entre fils
— Relier un cordon à chacun des deux fils.
Tourner le manivelle à une vitesse comprise entre 160
et 240 t.p.m. La valeur d’isolement sera lue sur
l’échelle ‘MΩ’ de l’indicateur. (Lors d’essais sur
circuits capacitifs, l’aiguille de l’indicateur se déplace
d’abord vers le zéro puis dévie graduellement jusqu’a
prendre une valeur fixe quand la capacité est chargée
à la tension de sortie de l’appareil.)
Si plusieurs mesures successives fournissent une
lecture ‘∞’, court-circuiter les extrémités des cordons
de mesure et tourner la manivelle de la génératrice.
Une lecture ‘zéro’ indique que les cordons ne sont ni
débranchés, ni coupés et que les mesures
d’isolement effectuées sont en fait correctes.
Les circuits capacitifs sont automatiquement
déchargés dans l’appareil quand on arrête de tourner
la manivelle — L’aiguille se déplace au delà de la
position ‘∞’ puis reprend sa position de repos sur la
marque ‘∞’ quand le circuit est déchargé. Attendre le
temps nécessaire pour que cette décharge se réalise
avant de débrancher les cordons d’essai. Le temps
de décharge est d’environ 8 secondes par microfarad.
ESSAIS DE CONTINUITE
Après avoir branché les cordons sur l’appareil, avoir
vérifié leur état ainsi que celui du fusible, placer le
commutateur de gamme sur ‘Ω’ — Une fois le circuit
en essai isolé, relier les cordons aux points à tester et
tourner la manivelle à une vitesse comprise entre 160
et 240 t.p.m. — La résistance est indiquées sur
l’échelle ‘Ω’ — Elle comprend la résistance des
cordons, qui doit être mesurée séparément (en court-
circuitant leurs extrémités), cette valeur doit ensuite
être retranchée du résultat de la mesure.
13

BETRIEBSANWEISUNG
ACHTUNG!
1. Vor der Isolierungs-oder Durchgangsprüfung muß
die zu prüfende Schaltung entladen und von der
Stromquelle getrennt werden.
2. Nach der Prüfung kapazitiver Schaltungen sind die
Testkabel kurzzeitig angeschlossen zu lassen,
damit sich die Schaltung entladen kann.
3. In staubiger Umgebung eingesetzte Geräte sind
regelmäßig zu warten und zu reinigen.
4. Das Gerät niemals längere Zeit direkter Wärme
durch Sonneneinstrahlung aussetzen.
VORPRÜFUNGEN
Das Testkab el auf gute nichtspröde Isolierung prüfen.
Mit Kabelklemmen abgeschlossenes rotes und
schwarzes Kabel verwenden Rote an (+), bzw.
schwarze (–) Anschlußbuchse an das Gerätgehäuse
anschließen. Die Kabel verdrillt bzw.
zusammengedreht lassen, jedoch darauf achten, daß
die Klemmen nichts berühren. Schiebeschalter auf
Stellung ‘MΩ’ bringen. Die Generatorkurbel mit etwa
160 Umdrehungen/MInute drehen und den
Meßgerätezeiger beobachten. Er soll auf der Stellung
‘∞’ (Unendlich) auf der Skale ruhen. Ist dies nicht der
Fall, können die Testkabel defekt sein, und sie sind
genauer auf eine Beschädigung zu untersuchen. Die
Kabel erforderlichenfalls ersetzen.
Die Kabelklemmen bzw. Enden verbinden und die
Generatorkurbel erneut drehen. Das Meßgerät soll nun
Null anzeigen. Liegt die Anzeige auf Unendlich oder
bei einem hohen Widerstandswert, kann eine
Kabelunterbrechung vorliegen. Die Kabel genauer
untersuchen und gegebenenfalls auswechseln.
Bei Kurzgeschlossenen kabeln zeigt die Anzeige 0 an
und man kann sich vergewissern ob das gerate
arbeitet.
Um zu prüfen, ob die Sicherung in der
Durchgangsschaltung in Ordnung ist, die Testkabel
zusammengeschlossen lassen und den
Schiebeschalter in die Stellung ‘Ω’ bringen. Die
Generatorkurbel erneut drehen: die Ablesung sollte
Null (oder fast Null) ergeben. Wenn die Anzeige im ‘Ω’-
Bereich über die volle Skale hinausgeht, ist die
Sicherung defekt und zu erneuern.
AUSWECHSELN DER SICHERUNG
Die Sicherung sitzt in einer Schraubhalterung
zwischen den Ausgangs-Anschlußbuchsen. Zum
Auswechseln der Sicherung den mittleren Teil des
Sicherungshalters mit einem Schraubenzieher lösen.
Die alte Sicherung mit einer keramic 1 A, 20 x 5 mm
ersetzen.
14

PRÜFEN DER ISOLIERUNG
Nach Anschließen der Testkabel an das Gerät und
Ausführen der oben genannten Vorprüfungen den
Schiebeschalter auf ‘MΩ’ stellen. Nachdem die zu
prüfende Schaltung von der Stromquelle getrennt ist,
die Tedstkabel wie folgt anschließen:
(a) Isolierungsprüfungen gegen Erde —
das rote Kabel auf Erde bzw. Rahmenmasse der
jeweiligen Ausrüstung legen und das schwarze
Kabel an den Teil der Schaltung anschließen ,der
getestet werden soll.
(b) Isolierungsprüfungen zwischen Drähten —
jeweils ein Kabel an die Drahtadern anschließen.
Die Generatorkurbel mit 160 bus 240 U/min drehen.
Der Gerätzeiger zeigt den Wert des
Isolationswiderstands auf der ‘MΩ’-Skale an. (Beim
Prüfen einer kapazitiven Schaltung geht der Zeiger
zunächst auf Null und steigt dann langsam auf den
endgültigen Ruhewert, während die Kapazität auf die
Ausgangsspannung des Prüfgeräts aufgeladen wird.)
Ergeben sich nacheinander mehrere Ablesungen von
‘∞’, die beiden anderen Enden der Testkabel
miteinander verbinden und die Generatorkurbel
drehen. Dabei sollte man nun eine Nullablesung
erhalten als Gegenprüfung dafür, daß die Kabel nicht
getrennt oder unter brochen sind und
Isolationswiderstandsablesungen somit korrekt sind.
Kapazitive Schaltungen entladen automatisch durch
das Prüfgerät, wenn die Generatorkurbel nicht mehr
gedreht wird. Der Gerätzeiger geht über die Stellung
‘∞’ auf der Skale hinaus und kehrt dann zur normalen
Ruhestellung bei ‘∞’ zurück, sobald sich die
Schaltung entladen hat. Einige Augenblicke warten,
damit die vollständige Entladung erfolgen kann, und
dann die Testkabel abnehmen. Die Entladezeit (auf
0 V) beträgt ca. 8 Sekunden pro Mikrofarad.
DURCHGANGSPRÜFUNG
Nach Durchführung der Vorprüfungen (wie bereits
beschrieben) und Anschluß der Meßleitungen den
Schiebeschalter auf die Stellung ‘Ω’ setzen. Die zu
prüfende Schaltung muß von der Stromquelle getrennt
sein. Die Testkabel an die zu messenden Punkte
anschließen und die Generatorkurbel mit 160 bis
240 U/min drehen. Der Widerstand wird auf der ‘Ω’-
Skale angezeigt. Dieser Widerstand enthält auch den
Widerstandswert für die Testkabel, der (durch
Ausführen eines Tests mit kurzgeschlossenen
Meßleitungen) separat zu messen ist; dieses Ergebnis
wird dann vom angezeigten Gesamtwert ab gezogen.
15

INSTRUCCIONES DE USO
ADVERTENCIA
1. El circuito bajo prueba debe ser descargado y
aislado antes de efectuar las pruebas de
aislamiento o continuidad.
2. Cuando se han probado circuitos capacitivos,
dejar transcurir un periodo de tiempo adecuado
antes de desconectar los cables, de modo que se
descargue el circuito, a través del instrumento.
3. Los instrumentos usados en condiciones
polvorientas, deben ser despiezados y limpiados
periodicamente.
4. Nos dejar los instrumentos expuestos a la luz
directa del sol durante largos periodos de tiempo.
COMPROBACIONES PRELIMINARES
Inspeccionar las sondas de prueba para cerciorarse
de que estén en buenas condiciones de aislamiento.
Conectar las sondas roja y negra rematadas en clips
en los enchufes terminales rojo (+) y negro (–)
respectivamente situados en el lateral del instrumento.
Pueden dejarse las sondas enrolladas o entrelazadas
una con la otra, pero ha de asegurarse que los clips
no hacen contacto con nada. Seleccionar el
interruptor deslizante en la posición “MΩ”. Girar la
manivela del generador en, aproximadamente,
160 r.p.m. y observar la aguja del indicador, la cual
deberá permanecer sobre la posición “∞” (infinito) de
la escala. Si esto no es asi, puede que estén
averiadas las sondas de prueba, y deberán
inspeccionarse mas detenidamente por si están
dañadas. Recambiarlas si es necesario.
Conectar los clips de las sondas nuevamente, girando
la manivela del generador.
Al conectarse los cables y oztener que marca (zero)
esto prueba que el instrumento funciona bein.
Para comprobar que está intacto el fusible incluido en
el circuito de continuidad, dejar los conductores de
prueba conectados y regular el interruptor deslizante
en la posición “Ω”. Girar nuevamente la manivela del
generador. La lectura deberá reflejar cero (o muy
cerca del mismo).
Si la aguja indica una lectura más allá de la escala
completa de la gamma “Ω”, el fusible se ha quemado
y deberá recambiarse.
RECAMBIO DEL FUSIBLE
El fusible es retenido en un alojamiento tipo roscable
situado entre los enchufes terminales de salida. Para
cambiar un fusible, usar un destornillador con el fin de
liberar la parte central del alojamiento que contiene el
fusible. Recambiar el viejo con un fusible de cerámic
1 A 20 x 5 mm.
16

COMPROBACION DE AISLAMIENTO
Después de conectar las sondas de prueba en el
instrumento y de efectuar las verificaciones indicadas
previamente, seleccionar el interruptor deslizante en la
posición “MΩ”. Con el circuito que ha de
comprobarse aislado, conectar los conductores de
prueba que sigue:
(a) Para las pruebas de aislamiento a tierra:
Conectar el conductor rojo a tierra o al bastidor del
equipo y el conductor negro en la parte del
circuito que se desea comprobar.
(b) Para las pruebas de aislamiento entre hilos:
Conectar un conductor en cada uno de los
núcleos de los hilos.
Girar la manivela del generador entre 160 y 240 r.p.m.
La aguja del instrumento indicará el valor de
resistencia de aislamiento en la escala de “MΩ”. (Si se
está probando un circuito capacitivo, la aguja se
desviará inicialmente hacia el cero, para luego,
gradualmente ascender hasta su valor final, a medida
que la capacitancia es cargarda hasta el voltaje de
salida del probador.)
Si se obtienen varias lecturas sucesivas “∞”, conectar
los dos extremos de los cables de pureba
conjuntamente y girar la manivela del generador.
Deberá obtenerse una lectura cero, con lo cual se
comprueba por partida doble que las sondas no están
desconectadas o rotas y que por consiguiente son
correctas las lecturas de aislamiento. Los circuitos
capacitivos se descargan automaticamente a través
del probado cuando se detiene el giro de la manivela
del generador. La aguja del medidor se desviará más
allá de la posición “∞” en la escala para luego
retornar a su posición “∞” cuando se ha descargado
el circuito. Aguardar unos momentos para que esto
ocurra antes de desconectar las sondas de prueba. El
tiempo de descarga hasta 0 V es, aproximadamente,
8 segundos por microfaradio.
COMPROBACION DE CONTINUIDAD
Con las sondas de prueba conectadas en el
instrumento, y una vez verificadas las sondas y el
fusible, como se describe anteriormente, seleccionar
el interruptor deslizante en la posición “Ω”.
Con el circuito que se está probando aislado,
conectar las sondas de prueba entre los puntos
apropiados y girar la manivela del generador entre
160 y 240 r.p.m. La resistencia será indicada en la
escala de “Ω”. Esta resistencia incluve a la de las
sondas de prueba, la cual deberá medirse
separadamente (efectuando una prueba con los clips
unidos), y el resultado deberá restarse del total.
17

SETTING-UP PROCEDURE
Notes on the basic setting-up procedure are given in
the table below. See ‘Repair and Warranty’ notes
opposite.
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Step Adjustment potentiometer Adjustment for Conditions for adjustment
1. R15 scale 10 MΩmark (a) switched to ‘MΩ’
(b) 10 MΩ(500 V rating) resistor across
(b) terminals.
2. R16 scale 0 MΩmark (a) switched to ‘MΩ’
(b) short circuit across terminals.
3. R14 scale 1 MΩmark (a) switched to ‘MΩ’
(b) 1 MΩ(500 V rating) resistor across
(b) terminals.
4. R17 scale 100 Ωmark (a) switch to ‘Ω’
(b) 100 Ωresistor across terminals.
WM6

REPAIR AND WARRANTY
The instrument circuit contains static sensitive devices,
and care must be taken in handling the printed circuit
board. If the protection of an instrument has been
impaired it should not be used, and be sent for repair by
suitably trained and qualified personnel. The protection is
likely to be impaired if, for example, the instrument shows
visible damage, fails to perform the intended
measurements, has been subjected to prolonged storage
under unfavourable conditions, or has been exposed to
severe transport stresses.
New Instruments are Guaranteed for 1 Year from the
Date of Purchase by the User.
Note: Any unauthorized prior repair or adjustment will
automatically invalidate the Warranty.
Instrument Repair and Spare Parts
For service requirements for Megger®Instruments
contact:-
Megger Limited or Megger
Archcliffe Road Valley Forge Corporate Center
Dover 2621 Van Buren Avenue
Kent CT17 9EN Norristown, PA 19403
England U.S.A.
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
or an approved repair company.
Approved Repair Companies
A number of independent instrument repair
companies have been approved for repair work on most
Megger instruments, using genuine Megger spare parts.
Consult the Appointed Distributor/Agent regarding spare
parts, repair facilities and advice on the best course of
action to take.
Returning an Instrument for Repair
If returning an instrument to the manufacturer for repair, it
should be sent, freight pre-paid, to the appropriate
address. A copy of the Invoice and of the packing note
should be sent simultaneously by airmail to expedite
clearance through Customs. A repair estimate showing
freight return and other charges will be submitted to the
sender, if required, before work on the instrument
commences.
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