Megger BITE 3, Instruction Manual

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Controls, Connectors, Indicators & Menus
AVTMBITE 3 Rev 8 April 2014
11
The keypad is used for entering site and string configurations. It is also used to
add comments about the battery or testing that the user may wish to document.
The keys’ character set is:
1( )
2ABC
3DEF
4GHI
5JKL
6MNO
7PQRS
8TUV
9WXYZ
0 (space), _
. ,.# m μ %-( ) /:@!?$=<>’*
The optional CT has two modes of operation: Escape current and impedance
(ripple current). It is necessary to measure “escape current” in short strings in
parallel configurations, mainly found in outside plant telco installations including
wireline and wireless applications. An example of this would be six battery
strings of (4) 12Vdc jars in each string.
In this example, the current from the measurement has parallel paths. The
instrument will measure its output current and the CT will measure the current
that is flowing through the parallel paths. The output current and the escape
current, together, provide accurate impedance values. Other methods that do not
measure current or the BITE 3 without the optional CT may have inherent
errors. By measuring the “escape” current, that is, the current that is not passing
through the battery being tested, it can be subtracted from the output current to
correctly calculate impedance following Ohm’s Law, Z=E/i.