HomeMy WebLinkAboutTab 1 - Controllogix Power Supply 1756-PA75Publication 1756-SG001E-EN-P - June 2002
Selecting a Power Supply 71
Selecting a Power Supply
ControlLogix power supplies are used with the 1756 chassis to
provide 1.2V, 3.3V, 5V, and 24V dc power directly to the chassis
backplane. Non-redundant (1756-PA72, -PB72, -PA75, -PB75) and
redundant (1756-PA75R, -PB75R) power supplies are available.
Selecting a non-redundant power supply
You mount a non-redundant power supply directly on the left end of
the chassis, where it plugs directly into the backplane. The power
supply you select can determine which chassis you can use. For more
information on selecting chassis, see page 67.
Step 6 - Select:
·one power supply for each chassis
·a power supply bundle if you are
planning a redundant power supply
system
Specification
Power Supplies Adapter
1756-PA72 1756-PA75 1756-PA75R 1756-PB72 1756-PB75 1756-PB75R 1756-PSCA
nominal input voltage 120V ac or 220V ac 24V dc na
input voltage range 85-265V ac 19.2-32V dc
maximum real input
power
95W 115W 97W 110W
maximum apparent
input power
240VA 120VA na
maximum transformer
load
238VA 120VA na
frequency 47-63Hz dc
maximum backplane
output current
1.5A @ 1.2V dc
4A @ 3.3V dc
10A @ 5V dc
2.8A @ 24V dc
75W total
1.5A @ 1.2V dc
4A @ 3.3V dc
13A @ 5V dc
2.8A @ 24V dc
75W total
1.5A @ 1.2V dc
4A @ 3.3V dc
10A @ 5V dc
2.8A @ 24V dc
75W total
1.5A @ 1.2V dc
4A @ 3.3V dc
13A @ 5V dc
2.8A @ 24V dc
75W total
hold up time(1)@60 Hz:
85V ac: 2 cycles
120V ac: 6 cycles
200V ac: 20 cycles
19V dc: 20 mS
24V dc: 70 mS
chassis compatibility series A
series B
series B series B series A
series B
series B series B series B
location left side of chassis panel mounted(2)left side of chassis panel mounted(2)left side of chassis
(1)The hold up time is the time between input voltage removal and dc power failure.
(2)Can be a maximum of 0.91 cable-metered (3 cable feet) from ControlLogix chassis.
Class I, Division 2, Group A, B, C, D Class I, Division 2, Group A, B, C, D N223
Publication 1756-SG001E-EN-P - June 2002
Selecting a Power Supply 73
Power Requirements and
Transformer Sizing
Each ac-input power supply generates a shutdown signal on the
backplane whenever the ac line voltage drops below its lower voltage
limit. It removes the shutdown signal when the line voltage comes
back up to the lower voltage limit. This shutdown is necessary to help
ensure that only valid data is stored in memory.
The external transformer rating (in VA) of each power supply is
greater than its real input power (in Watts) because a capacitor-input
ac/dc supply draws power only from the peak of the ac voltage wave
form. If the transformer is too small, it clips the peak of the sine wave;
when the voltage is still above the lower voltage limit, the power
supply will sense this clipped wave form as low voltage and could
prematurely shut down modules in the chassis.
The following graphs display the backplane power load on the
vertical axis. Since these supplies have multiple outputs, the
backplane power load is given in watts.
·Use the real power value in watts for determining the amount of
heat dissipation you will have inside the enclosure.
·Use the apparent power value in VA for estimating power
distribution sizing.
·Use the transformer load value in VA of each power supply plus
all other loads on a transformer to determine the required
transformer size.
Publication 1756-SG001E-EN-P - June 2002
74 Selecting a Power Supply
Power load and transformer sizing
backplane
power load
(Watts)
backplane
power load
(Watts)
75
60
45
30
15
0 0 20 40 60 80 100 0 50 100 150 200 2500 20 40 60 80 100
75
60
45
30
15
0
75
60
45
30
15
0
75
60
45
30
15
0 0 20 40 60 80 100
real power (Watts) apparent power (Watts)
real power (Watts)
1756-PA72
1756-PA75
ac
1756-PB72
1756-PB75
dc
backplane
power load
(Watts)
1756-PA75R
ac
backplane
power load
(Watts)
real power (Watts)
1756-PB75R
dc
75
60
45
30
15
0
0 20 40 60 80 100 120
real power (Watts) apparent power (Watts) transformer load (VA) =
real power (Watts)1
75
60
45
30
15
0
0 20 40 60 80 100 120 0 20 40 60 80 100
75
60
45
30
15
0 0 50 100 150 200 250
75
60
45
30
15
0
transformer load (VA) =
real power (Watts) x 2.5
1 Power factor circuitry reduces transformer sizing requirements.