User Manual

Power Cabinet Initial Power Up – continued

PRELIMINARY 2

SC 4812ET BTS Optimization/ATP – CDMA LMF

July 1999

2-6

Table 2-4: Battery Charge Test

Step Action

4 The bargraph meters on the rectifier modules can be used as a rough estimate of the total battery

charge current. Each rectifier module has eight (8) LEDs to represent the output current. Each

illuminated LED indicates that approximately 12.5% (1/8 or 8.75 Amps) of the rectifiers

maximum (70 Amps) current is flowing.

EXAMPLE:

Question: A system fitted with three (3) rectifier modules each have three bargraph LEDs

illuminated. What is the total output current into the batteries?

Answer: Each bargraph is approximately indicating 12.5% of 70 Amps, therefore, 3 X 8.75 equals

26.25 Amps. As there are three rectifiers, the total charge current is equal to (3 X 26.25 A) 78.75

Amps.

This charge current calculation only applies at this part of the start up procedure, when the RF

Cabinet is not powered on, and the power cabinet heat exchanger is turned off.

5 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 5A.

6 Recheck the DC output voltage. It should remain the same as measured in step 4 of the Power Up

Test.

NOTE

If discharged batteries are installed, all bargraphs may be illuminated on the rectifiers during the

charge test. This indicates 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.

RF Cabinet Power Up

Table 2-5 covers the procedures for properly powering up the RF

Cabinet.

Table 2-5: RF Cabinet Power Up

Step Action

1 Turn the 400 Amp Main DC breaker in the RF Cabinet ON.

NOTE

Ensure that no alarms or voltage change has occurred in the power cabinet, and that the power

cabinet Main DC breakers have not tripped. The rectifier bargraph readings should be the same as

before the main breaker in the RF cabinet was turned ON.

2 Proceed to RF cabinet power up sequence.

3 The RF Cabinet ATP procedure can now proceed in parallel with the remaining Power Supply

Cabinet tests.

. . . continued on next page