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Power Supply Calculations Calculating the System Current Draw
46 MS-2/MS-4 PN 51512:E 01/18/05
Table 5-3 contains three columns for calculating current draws. For each column,
calculate the current and enter the total (in amperes) in the bottom row. When finished,
copy the totals from Calculation Column 2 and Calculation Column 3 to Table 5-4 on
page 47.
TABLE 5-3:System Current Draw Calculations
Device Type
Calculation Column 1
Primary, Non-Fire Alarm Current
(amps)
Calculation Column 2
Primary, Fire Alarm Current
(amps)
Calculation Column 3
Secondary, Non-Fire Alarm Current
(amps)
Qty X[current draw]= Total Qty X [current draw] = Total Qty X[current draw]= Total
Main Circuit Board
MS-2
or
MS-4
1
X[0.080]=
X[0.085]=
0. 1
X[0.112]
1
=
X[0.175]
1
=
0. 1
X[0.080]=
X[0.085]=
0.
CAC-4 [ ] X[0.001]= [ ] X[0.001]= X[0.001]=
4XTMF [ ] X[0.005]= [ ]
X[0.011]
1
=
X[0.005]=
4XZMF [ ] X[0.004]= [ ] X[0.008]= X[0.004]=
4XLMF/RZA-4XF pair
[ ]
1 pair max.
X[0.004]= [ ] X[0.019]= X[0.004]=
2-wire Detector Heads [ ]
X[ ]
2
=
[ ] X[ ]= X[ ]=
4-wire Detector Heads [ ]
X[ ]
3
=
[ ] X[ ]= X[ ]=
Power Supervision
Relays
4
[ ] X[0.025]= [ ] X[0.025]= X[0.025]=
NAC #1
5
[ ] X[ ]=
NAC #2 [ ] X[ ]=
Current Draw from
TB1 (nonalarm
6
)
[ ]= [ ]= [ ]=
Sum each column
7
for
totals Primary Non-Alarm = Primary Alarm = Secondary Alarm =
Table Footnote
1. If using the Reverse Polarity Alarm output, add 0.005 amps; if using the Reverse Polarity Trouble output, add another 0.005
amps.
2. Refer to the Device Compatibility Document for standby current.
3. Refer to the Device Compatibility Document for standby current.
4. Must use compatible listed Power Supervision Relay.
5. Current limitation of Terminal TB2 circuits is 2.50 amps per NAC (MS-4 requires optional transformer for max. current)
6. The total standby current must include both the resettable (TB1 Terminals 3 & 4) and nonresettable for MS-4 only (TB1 Termi-
nals 1 & 2) power. Caution must be taken to ensure that current drawn from these outputs during alarm does not exceed maxi-
mum ratings specified. Current limitations of TB1, Terminals 1 & 2 = 0.500 amps, filtered, 24 VDC +/-5%, 120 Hz ripple @ 10
mV
RMS
, nonresettable power and TB1, Terminals 3 & 4 = 0.500 amps, filtered, 24 VDC +/-5%, 120 Hz ripple @ 10mV
RMS
,
resettable power.
7. Total current draw listed above cannot exceed 3.0 amps with only standard transformer installed or, for the MS-4, 6.0 amps with
both the standard and optional transformers installed.