Atec Megger-bite-3 - Manual (Page 2)

Figure 1: Battery Analysis Report
BITE ® 3
Battery Impedance Test Equipment
systems, operating controls, switchgear components,
protective relays and continuous process systems. Failure
of a battery system within environments such as utilities,
hospitals and manufacturing plants can result in
operational failure of the devices connected to it. ProActiv
assists the user to avoid battery failures, budget for future
battery string and cell replacements, and plan battery
changeouts in an orderly manner.
The BITE 3 along with ProActiv software offer the most
comprehensive data analysis system to provide confident
and reliable evaluation of batteries in the dc network.
Together, they combine to make the most powerful battery
health analyzer available on the market today.
APPLICATIONS
It is known that impedance is correlated to battery
capacity and there has been a long-standing question as to
when a user should replace a cell. See Figure 2. Recent
studies by EPRI* and other organizations indicate that
when the impedance of a sealed battery increases by
about 50% from its baseline value, the cell has degraded to
less than about 70% capacity. BITE 3 and ProActiv allow
the user to trend data and to enter baseline values for
comparison purposes and to make decisions whether on-
site or in the office. Both the BITE 3’s impedance
deviation graph and the trend graph in ProActiv clearly
show the status of a cell which helps users to decide what
action needs to be taken to ensure battery back up
reliability based on users’ criteria.
A battery’s internal impedance increases as its capacity
decreases due to various factors such as age, ambient
temperature, discharge history, etc. The BITE 3 measures
internal impedance and dc voltage for lead-acid cells up to
2000 Ah in capacity. It also measures intercell connection
resistance, float current and ripple current and the
harmonic content of the ripple current to provide a much
better evaluation than any other single instrument.
Impedance finds electrical path problems due to plate
sulphation, post-seal corrosion, dry-out (loss of
compression), poor intracell welds and intercell
connections and more. These data let the user determine
maintenance needs such as:
■ Cell replacement criteria based on impedance trends
■ Jumper out a cell or two
■ Clean and/or retighten intercell connectors
■ Shorten the maintenance interval, etc.,
■ Evaluate float current and ripple current effects
Typical installations that can be tested using the BITE 3
include:
■ Electrical power generation plants
■ Substations — utility, railroad, industrial
■ Telecommunications facilities — OSP, Wireless, POPs,
MTSOs, Fiber Regens
■ UPS systems — standard and cabinetized batteries
■ Railroad — Signals and Communications, CTC
■ Aircraft power supplies
■ Marine and military
*Stationary Battery Monitoring by Internal Ohmic Measurements
EPRI, Palo Alto, CA: 2002. 1002925