Juniper SRX5400 Hardware Manual page 158

Table 39: Calculating Power Budget, AC-Powered Chassis
Maximum Output Power of
Power Supply
1167 W (low-line)
2050 W (high-line)
Table 40: Calculating Power Budget, DC Powered Chassis
Maximum Output Power of Power
Supply
2400 W (DIP=0)
2600 W (DIP=1)
3. Calculate input power. In this step, the input power requirements for the example configuration are
calculated. To do this, divide the total output requirement by the efficiency of the power supply as
shown in Table 41 on page 159
Table 41: Calculating System Input Power
Power Supply
SRX5400 AC
SRX5400 DC
1
These values are at full load and nominal voltage.
4. Calculate thermal output (BTUs) for the system. To calculate this value, multiply the total input power
requirement (in watts) by 3.41 as shown in
Maximum Output Power for System
1167 x 2 = 2334 W
(2+1 Redundancy)
2050 x 2 = 4100 W
(2+1 Redundancy)
Maximum Output Power for System
2400W
(1+1 Redundancy)
2600W
(1+1 Redundancy)
Here we include the power drawn by the cooling system.
Power Supply Efficiency
89 %
~98 %
Table 42 on page
Unused Power
2334 - 2282 = 52W
4100 - 2282 = 1818 W
Unused Power
2400 - 2282 = 118W
2600 - 2282 = 318 W
1
Input Power Requirement
2282/0.89 = 2564 W
2282/0.98 = 2329 W
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