Input power requirements and transformer sizing – Rockwell Automation 1756-xxxx ControlLogix Chassis and Power Supplies Installation Instructions User Manual
Page 53
Rockwell Automation Publication 1756-IN005C-EN-P - March 2014
53
Install Chassis and Redundant Power Supplies
Chapter 2
Input Power Requirements
and Transformer Sizing
These graphs show the input power requirements for the power supplies, given
the power they are providing to the modules in the chassis.
Follow these steps to determine the power requirements for your chassis.
1. Calculate the Backplane Power Load by adding the power draw (in Watts)
for all of the planned modules.
Refer to the module specification tables in the ControlLogix Selection
Guide, publication
r module power draws.
2. Locate the Backplane Power Load on the graph’s vertical (y) axis and
determine the corresponding Real Power (input-power) rating on the
horizontal (x) axis.
The Real Power value is the amount of power consumed by the power
supply.
Figure 37 - Power Supply Power Requirements
For more information about calculating the required power for your system, see
the ControlLogix Selection Guide, publication
.
0
7
14
21
28
35
42
10
20
30
40
50
60
70
80
0
75
6
0
7
14
21
28
35
42
10
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0
64
6
75
60
45
30
15
0
0 20 40 60 80 100 120
115
13
75
60
45
30
15
0
0 20 40 60 80 100 120
110
7
43588
1756-PA75R/A (AC)
Backplane Power
Load (Watts)
Real Power (Watts)
Real Power (Watts)
Backplane
Power Load
1756-PB75R/A (DC)
43589
1756-PAXTR (AC)
Backplane Power
Load (Watts)
Real Power (Watts)
Real Power (Watts)
Backplane Power
Load (Watts)
1756-PBXTR (DC)
Apparent Power (Watts) = Transformer Load (VA) = Real Power (Watts)
43897
43898