11(57)
Datum/Date
Rev
Dokumentnr/Documentnr
Uppgjord/Prepared
Dokansv/Godkänd - Doc respons/Approved
Kontr/Checked
Tillhör/Referens-File/Reference
1999-07-15
V
1531-BDV 113 08 Uen
INSTALLATION INSTRUCTION
Faktaansvarig - Subject responsible
4.6
Power supervision on ELU-A
The ELU-A board is equipped with an automatic traffic limiter restricting the internal power dissipation on the board to
a maximum of 12 W. This depends on both the line length and the number of lines busy.
When the power consumption exceeds this limit, no more lines can be accessed and until at least two lines go on
hook again are all lines accessible.
When connecting external voice systems a maximum of 8 lines are recommended on each board. The remaining
lines on the board are to low traffic extensions.
4.7
System Power Consumption
The power demand of the system comprises the sum of the current demands of all extensions, base stations etc.
This total current has to be delivered by the power supply. Choose the one delivering the rated current with a suitable
margin for add on equipment depending on the installation site.
Base Station Power Demand
To minimise the power dissipation on the serial communication wires EPP should be used extensively. Up to 60 BS
can be installed in a cabinet. Short power peaks can be covered by installing a battery cabinet.
The current limit for remote feeding to the BS per IC-LU is 1.5A on the 48V if supplied from the backplane and 2.1A
when supplied via an external power input at the front of the connector. The total current for all BS must be less than
the power supply(s) capacity. The total 48 VDC load on the power supply has to be calculated as follows:
1417mA
Total current for all Base Stations is:
Assuming 7 Base Stations are already
3175mA
Total load on power supply:
4592mA
1300 mA
This total load for the exchange can be supplied by the bat-
tery charger as it is less than 5A.
Power demand taken from Power Calcu-
lations below, for telephones, boards:
Cable
100m
200m
300m
400m
500m
600m
700m
800m
1,1km
1,2km
1,3km
1,4km
1,5km
1,6km
length
0m
STD
EPP
104
110
114
104
106
110
112
115
119
121
125
129
121
129
104
108
110
114
118
104
106
108
109
110
112
114
117
118
STD
EPP
0,5 mm
∅
0,6 mm
∅
connected they consume a current of:
(This current can be supplied by the back plane)
900m
1,0km
152
160
171
183
133
139
146
204
127
129
131
135
121
123
125
137
Line length to Base Station:
Resistance of loop:
Cable diameter (
φ
):
700m
0.18
Ω/
m
0,6 mm
Calculation example:
This table states the current demand in mA for a Base Sta-
tion depending on the cable length and cable diameter.
117 mA
Current of BS 0,6 (
φ
) and 700m:
+
STD
EPP
77
83
87
104
106
110
112
115
119
121
125
129
94
103
104
108
110
114
118
104
106
108
109
110
112
114
117
118
STD
EPP
0,5 mm
∅
0,6 mm
∅
152
160
171
183
133
139
146
204
127
129
131
135
121
123
125
137
