PS Magazine - TB 43-PS-583
PS, The Preventative Maintenance Monthly
ISSUE 583
JUNE 2001
PS 583
PS 583
JUN 01
56
Mobile Subscriber Equipment…
Y
our shelter runs on AC or DC power with two batteries as emergency backup.
Some of you have the new maintenance free batteries, but many shelters still have the
lead-acid ones. If you lose power from your primary source, the backup batteries will
keep the workstation going until primary power can be restored.
But as your shelter sits idle, the voltage level on those lead-acid batteries drops. To
make sure you still have your backup ready, you must do an initial load/charge test on
the batteries during the AC power initialization procedure like it says in your TM:
Here’s
how to do
that test:
1.
Make sure the BATTERY ON BUS indicator and REGULATOR CHARGER ON
indicators on the power control panel are on.
2.
Set the CURRENT SELECT switch to CHRG (charge).
3.
Press and hold the CHARGE-TEST button for 1 minute. After a minute, the DC
CURRENT meter will show the charger current. Write down the reading.
4.
Release the CHARGE-TEST button.
5.
Set the CURRENT SELECT switch to LOAD.
6.
Press and hold the CHARGE-TEST button for 1 minute. After a minute, the DC
CURRENT meter will show the load current.
7.
Subtract the load current from the charger current. If the difference is greater than
5 amps, the batteries need charging.
Battery Charging
To charge the batteries, press the
EQUALIZING CHARGE button on the
power control panel. The EQUALIZING
CHARGE indicator will come on and the
BUS VOLTAGE meter will increase to 28
volts. This starts a 5-hour charge cycle.
But it may not take the whole 5 hours
to charge the batteries! You must monitor
the charge by doing the load/charge test
every half hour. When the test shows that
the difference between the charger cur-
rent and load current is 5 amps or less,
stop charging!
If you keep the charger
running, you’ll overcharge the batteries
and damage them.
Stop the battery charge cycle by rapid-
ly switching the BATTERY CHARGER
circuit breaker OFF and then back ON.
If the difference between the charger
current and the load current will not come
to within 5 amps after 5 hours, there’s a
problem with the charging system. Stop
the charge cycle.
It’s not done automat-
ically!
Then get your support on the job.
During operation, follow-up load/charge tests should be done at least once a day
and at shift changes. But the equalizing/charge cycle must not be done again! It
should only be done during the AC power initialization procedure like your TM says.
If your daily or shift-change
load/charge test shows the dif-
ference between the charger
current and the load current is
more than 5 amps, do the reg-
ulator/battery charger adjust-
ment found in your operator
TM. If this does not solve the
problem, call your support.
Now we’re
ready for
anything!
When you’re charging
me, do the load/charge
test every half-hour
If the test shows
the difference between
charger
current and
load
current is
5 amps or less,
stop charging!
Operators,
your
MSE shelter
needs its lead-acid
backup batteries
recharged.
but some
of you are
not
doing it.
583. 56-57 (C)
5/2/01
2:35 PM
Page 1
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