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Background
Backup
battery failures can be catastrophic. In
Central Offices, Switching Systems or Radio installations, etc.,
that require a battery backup power source, generally there is
no real-time health checking of batteries.
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Under normal operating conditions, the system is
powered from commercial AC supply, and the batteries are kept in trickle or float
charge mode. The charger is set to supply system power and it charges
the batteries at the same time. The charger does not provide any information
about the health of individual batteries. It does not have such capability.
Backup batteries are only used when commercial AC power is lost. The
batteries are checked only during a periodic maintenance (6 months
or 1 year schedule). If a battery degrades or goes bad (Plates
short or open, partially or fully) between maintenance schedules,
it can not be detected. A bad battery can not deliver necessary
power during critical AC power failures. Vital communications
may be lost or system may just shut itself. A situation like
this at an air traffic control center, at a radio site or an
airport may cause a serious safety problem. Communications with
the airplanes and other facilities may be lost.
DSP, Inc.
has designed a Battery Monitoring system that constantly checks
the health of each battery every second and reports their status
every 10 seconds. If a battery degrades or fails an audio/visual
alarm is provided to the operator or maintenance staff. You do
not have to find a bad battery in your backup system the hard
way, at the time when you need it the most.
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| Operation
The
DSP Inc. has designed a digital signal processor based Battery Monitor
that performs a real time analysis of individual batteries. The processor
calculates voltage levels of each battery. It checks for opens, shorts,
degraded battery (terminal voltage above or below min/max limits),
undercharge and overcharge conditions. If a battery voltage does
not meet the profile or template of a “Healthy” battery, the unit
declares a failure and provides an audible and visual alarm. A
12 bit A/D circuit combined with a floating point DSP algorithm
provides a voltage accuracy of better than 50mV. An individual
LED indicates health of each battery (Green, Yellow or Red for
Healthy, Partial and Bad battery, respectively). Using a RS-232
terminal the unit can be interrogated remotely to provide detailed
voltage and health status on demand. A summary alarm relay contact
and an RS-232 data port combined with DSP, Inc.'s unique design
provides a comprehensive and reliable monitoring system that can
foretell backup power problems before they happen.
Typically,
a unit monitors up to eight 6 Volt or four 12 Volt batteries in a Negative
or Positive battery system. Different models are available to monitor
other battery voltages and number of batteries. The unit operates from
a small AC Brick and occupies only 1.75-inch (1U) rack space in a 19
or 23-inch rack. The unit draws a negligible amount of current (Less
than 5 ma) from the batteries. With the DSP, Inc.'s Battery Monitor
in your installation, battery degradations are reported quickly
before a failure occurs, eliminating the need for a periodic maintenance
action.
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