Atec Megger-bite-3 - Manual (Page 3)

drop of the intercell connector to calculate the resistance
of the intercell connector. Then, it measures the strap
again without the instrument current. A mathematical
calculation is performed to determine float and ripple
currents and the intercell connection resistance.
The optional CT can be used with short strings in parallel
configurations to measure “escape current.” Other
techniques do not measure the current and can overstate
the health of batteries in these types of configurations. By
using a CT to measure the actual current in the cell being
tested, better results are obtained.
ProActiv can download string header info (with baselines
and limits) into the BITE 3 along with the most recent data
(even if measured by a different BITE). See Figure 3. Then
using the menus, simply scroll to the site and string and
start taking readings. When finished, close the test and
continue to the next string. At the conclusion of the test,
simply download to a PC for further data analysis and
long-term trending. Its versatility allows comments to be
added about the string. These comments will be uploaded
with the battery data. Additional comments about the site,
string and/or cell such as ambient and pilot cell
temperature can be stored by using the keypad to enter
them.
DATA ANALYSIS
The interface between BITE 3 and ProActiv is an
advanced, state-of-the-art feature that ensures that
everyone has access to the latest information and data on
which to base intelligent battery decisions. Not only can
emergency cell replacement criteria be developed but also
budgetary planning for string replacements can now
become part of the fiscal planning process.
ProActiv has the ability to download site and string
information and data as well as firmware updates to the
BITE 3. The data downloaded into the BITE 3 gives access
to the most recent data for the strings being tested during
the upcoming week or month.
BITE ® 3
Battery Impedance Test Equipment
FEATURES AND BENEFITS
■ Calculates impedance automatically
and stores results for on-site review to
make immediate decisions.
■ Serial connector for uploading stored
data to a personal computer and to
download data from ProActiv.
■ Measures lead-acid cells up to 2000 Ah
to test a wide range of batteries.
■ On-line testing requiring no downtime
and introduces less risk to battery
testing compared to load testing and
other techniques.
■ Stores more than 1 million cells’ data
in any string configuration – no need
to stop, download, delete and continue.
■ Firmware and software updates are fast and easy for
ProActiv and the BITE 3 through the Internet.
■ No programming skills required. ProActiv is an easy to
use, fully functional battery database capable of storing
as much information and data as your hard drive (or
network) has memory to store.
■ ProActiv has the ability to import images such as IR
thermographs, diagrams or photographs. This helps to
document visual inspections, string configurations,
installation techniques, or other aspects of battery
systems. Images and data are stored together, providing
convenient and easy access.
■ The BITE 3 and ProActiv accommodate multiple
languages.
TEST PROCEDURE
The BITE 3 works by placing the lead set at the cell
terminals to measure the voltage drop of the ac current
signal applied by the instrument to the cell while it is
on-line. During each measurement, impedance is
calculated following Ohm’s Law, displayed on the LCD,
and stored. It also measures, displays and records dc
voltage, interconnection (strap) resistance, float and ripple
currents. Float and ripple current measurements are
performed separately at the start of the test. This is
because current is the same everywhere in the series
connection of the string in accordance with Kirchhoff’s
law. All of these data together help determine the overall
health of the entire battery string’s electrical path from
terminal plate to terminal plate and to a lesser extent, the
charger (by measuring ripple current and its harmonic
content).
An innovative, patent-pending measuring technique is
being employed so that a clamp-on current sensor is no
longer necessary. It is well-recognized that the best way to
measure current is with a shunt. Since the battery has
many straps, simply by determining a strap’s resistance, it
can be used as a shunt to determine float and ripple
currents. First, while across an intercell connector, the
instrument applies a current and measures the voltage
Figure 2: Ascending impedance compared to load test