System Planning
Determine D.C. Power Requirements
Summary:
The Telecenter IV standard 12 Vdc power supply is adequate unless unusual demands
are
placed
on the system. Use the example shown below and complete the following
steps to de-
termine
if
additional
power handling capacity is required.
The example represents
a system with 5
TC4150 LLM’s and 3 TC4160 VCMs. One 10 watt
speaker is used and all others are under 2 watts each. It is assumed that at most 20 phones
will be off-hook at once and that it is possible for three administrative phones to place simul-
taneous intercom calls (no idle
VCM’s) .
The result of the computation (6.72 amps) indicates the TC4OOls built-in 5 amp power
supply is insufficient. To install all three VCMs, a separate 4.0 amp regulated power supply is
required.
step 1. Note the total number of TC4150 LLMs in the system in the formula for LLMs.
step 2. Estimate the maximum number of multi-link phones that may be off-hook at any given time.
(32 off-hook phones will use all sixteen lines.) Note this number in the formula for Off-Hook
Phones.
Step 3. Review the power rating of each speaker assigned to each VCM.
Note the number of VCMs with all speakers rated at no more than than 2 watts in the
formula for 2W VCMs.
Note the number of VCMs with any speaker rated above 2 watts in the formula for
12w VCMS.
step 4. Estimate the maximum number of administrative phones that may make simultaneous
intercom calls. Subtract this number from the total number of VCMs installed and note the
remainder in the formula for IDLE VCMS.
Step 5. Perform the indicated calculations to determine the system total power requirement and plan
for additional power if it exceeds 5 amps.
D.C. Power Requirement Formula
(Example)
MI0 + CPU + MTGlOO
=
1.80
Off-Hook Phones
Number 5
X
.08 =
.40
Number 20 X
.04 =
.80
VCM2s:
Idle
2 w
12w
Number
Number
Number
X
.30 =
2 X
.66
= 1.32
1 X 2.40 = 2.4
Total Amps
=
6.72
1989 Rauland-Borg Corporation (Orig. 10/88; Rev. 1b.39)
Page 11 of 16
