Measurement In High Fault Energy Situations; Voltage Measurement - Megger AVOMETER 8 Mk7 Guia Del Usuario

A 10 A fuse in series with the 'COMMON'
terminal gives increased protection to the user
should the instrument be incorrectly used in high
energy situations.
MEASUREMENT IN HIGH FAULT ENERGY
SITUATIONS
Particular care must be taken with all testing
equipment when making measurements in high
fault energy situations, e.g. main power
distribution systems.
Always ensure the correct range is selected before
connecting the instrument to the circuit under
test.
Fused test leads, fitted with High Rupture
Capacity fuses, can be used to increase user
safety in the event of incorrect range selection. It
is most important when fused leads are used, that
the continuity of the test leads be checked before
every measurement. This may be performed as
follows: select the lowest resistance range;
connect the test leads to the instrument and short
together the test prods or clips; check that the
resistance is low.
Note:– The instrument itself has a 10 A fuse for
added protection but this does not negate the
need for test leads with fused prods.
Suitable test leads with fused prods and clips can
be obtained as an optional accessory, part no.
6111-287.

VOLTAGE MEASUREMENT

When measuring voltage, it is necessary to set the
appropriate switch to "AC ~" or "DC . . ." as
required and to select the required range (on the
other switch). Connect the test leads to the circuit
to be measured.
If the value of the voltage is unknown, set the
instrument to its highest range, connect the test
leads and decrease the range step by step until
the most suitable one has been found. The
readings are taken from the 0-3 or 0-10 scale and
multiplied by the appropriate factor i.e. 10, 100 or
1000.
When measuring high a.c. and d.c. voltages (say
above 800 V) unless the common negative
terminal is either earthy or connected to earth,
errors will be introduced if the instrument is
touched during a measurement.
On the d.c. ranges, the meter consumes only 50
microamps at full scale deflection corresponding
to 20 000 Ω/V. In the case of the a.c. ranges
above consumption of 0,5 mA (2000 Ω/V). The
10 V a.c. range is 1000 Ω/V and therefor e
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