User's Manual

Table Of Contents
Applying AC Power
68P64115A18–1
Mar 2003
1X SC 4812T Lite BTS Optimization/ATP Software Release R2.16.1.x
DRAFT
2-14
Table 2-7: Battery Charge Test (Connected Batteries)
Step Action
NOTE
The MAP AMP display will indicate the total current output of the rectifiers during this procedure.
As an alternative, the bar graph meters on the AC rectifier modules can be used as a rough estimate of
the total battery charge current. Each rectifier module bar graph has eight (8) LED elements to
represent the output current. Each illuminated LED element indicates that approximately 12.5% (1/8
or 8.75 Amps) of an individual rectifiers maximum current output (70 Amps) is flowing.
RECTIFIER BAR GRAPH EXAMPLE:
Question: A system fitted with three (3) rectifier modules each have three bar graph LED elements
illuminated. What is the total output current into the batteries?
Answer: Each bar graph is indicating approximately 12.5% of 70 amps, therefore, 3 x 8.75 equals
26.25 amps per rectifier. As there are three rectifiers, the total charge current is equal to (3 x 26.25 A)
78.75 amps.
This charge current calculation is only valid when the RF and PA compartment electronics are not
powered on, and the RF compartment heat exchanger is turned off. This can only be accomplished if
the DC PDA MAIN BREAKER is set to OFF.
3 The current in each string should be approximately equal (within + 5 amps).
4 Allow a few minutes to ensure that the battery charge current stabilizes before taking any further
action. Recheck the battery current in each string. If the batteries had a reasonable charge, the current
in each string should reduce to less than 5 amps.
5
Recheck the DC output voltage. It should remain the same as measured in step 4 of the frame DC
Power Application and Test (Table 2-6).
NOTE
If discharged batteries are installed, the MAP AMP display may indicate approximately 288 amps for
a two–carrier frame (four rectifiers) or 216 amps for a single–carrier frame (three rectifiers).
Alternately, all bar graph elements may be lighted on the rectifiers during the charge test. Either
indication shows that the rectifiers are at full capacity and are rapidly charging the batteries. It is
recommended in this case that the batteries are allowed to charge and stabilize as in the above step
before commissioning the site. This could take several hours.
Battery Discharge Test
Perform the test procedure in Table 2-8 only when the battery current is
less than 5 Amps per string. Refer to Table 2-7 on the procedures for
checking current levels.
Table 2-8: Battery Discharge Test
Step Action
1 Turn the BATT TEST switch on the MAP ON (Figure 2-5). The rectifier output voltage and current
should decrease by approximately 10% as the batteries assume the load. Alarms for the MAP may
occur.
2 Measure the individual battery string current using the clamp–on DC current probe and DMM. The
battery discharge current in each string should be approximately the same (within +
5 amps).
3 Turn BATT TEST switch OFF.
2