CHAPTER 2 ND-71548 (E)
Page 12
Issue 2
INSTALLATION DESIGN
Note 1: When the rectifier is in the equalize state (charging the batteries), the output DC voltage should be 1.5 to
2 volts higher than the float voltage. Examples of the voltages for floating and equalizing are listed below:
Float: 50.5 V DC
Equalize: 52 V DC (Refer to Note 2.)
Note 2: The Equalize voltage is 1.5 to 2 V higher when an EMF panel (Diode Drop) is utilized. When an EMF panel
is not provided, the Float and Equalize Voltage must be the same (50.5 V).
Note 3: The main source power is AC input.
Note 4: Noise caused in the -48 V output from the rectifier should be less than 5 mV.
6.2 Current Consumption
The PBX operates on -48 V ±5 V DC which is supplied from external power equipment (the rectifier and the
battery).
Various DC voltages required within the system are provided by the DC-DC converter in each module. The DC-
DC converter, upon receiving the -48 V DC source power, converts it into various DC voltages and supplies
them to the associated circuits.
Figure 2-2 shows the current consumption of the PBX.
Figure 2-2 Current Consumption of the PBX
(AMPS)
35
30
25
20
15
10
5
100 200 300 400 500 600 700 800 900 1000
No. of PORTS
DC
-48V