Megger ATEC 210415 Series, Manual

Page: 39 / 82

M
32
AVTM21-415Ja Rev. A June 2005
These voltages are used because they are called for in dc testing
of commonly encountered services. In addition, tests can be
run at any voltage up to 15 kV.
Resistance at any other test voltage within the range of the
Catalog No. 210415 can be computed by the following:
V
V
x
R R
c
c V
=
where: V= actual test voltage
V
C
=
standard voltage of either 5 or 10 kV as
selected by full scale range of 7.5 or 15 kV
R
C
=
indicated resistance on scale corresponding to
selected V
C
R
V
= actual resistance being measured at voltage V
The factor
V
V
c
can be read directly from the lower (green) scale
of the Voltmeter.
When the test voltage is set to one of the standard voltages 5
kV or 10 kV as in the normal usage, the equation reduces to
the direct-reading case, namely:
R
R
c
V
=
To summarize, the following rules hold for all situations:
1. Read megohms on the scale corresponding to the
voltmeter range, matching red (inner) scales and black
(outer) scales.
2. Multiply by the megohmmeter range setting.
3. Multiply by the reading from the voltmeter lower green
scale.