Rockwell Automation Publication 1606-RM028A-EN-P - September 2021
21
Example Repetitive Pulse Calculation
A load is powered continuously with 480 W (= 50% of the rated output load).
Occasionally a peak power of 1440 W (= 150% of the rated output load) is
needed for 1 second.
How often can this pulse be supplied without overloading the power supply?
1. Make a vertical line at P
PEAK
= 150% and a horizontal line where the
vertical line crosses the P
0
= 50% curve. Read the maximum duty cycle
from the duty cycle-axis (= 0.37)
2. Calculate the required pause (base load) length T
0
3. The result is the required pause length = 1.7 s
4. Max repetition rate = pulse + pause length = 2.7 s
Figure 38 - Repetitive Pulse Loads, Definitions
Figure 39 - Maximum Duty Cycle Curve
g
100%
P
PEAK
T
PEAK
P
0
T
0
max
150%
1
P
0
Base load (W)
P
PEAK
Pulse load (above 100%)
T
0
Duration between pulses (s)
T
PEAK
Pulse duration (s)
150%
100
0
0.2
0.4
0.6
0.75
Duty Cycle
110
120
130
140
P
PEAK
P
0
= 10%
P
0
= 50%
P
0
= 75%
P
0
= 100%
1
DutyCycle
=
T
peak
T
peak
+ T
0
T
0
=
T
peak
- (DutyCycle x T
peak
)
DutyCycle
T
0
=
T
peak
- (DutyCycle x T
peak
)
=
1 s - (0.37 x 1 s)
=
1.7 s
DutyCycle
0.37
Additional Examples for Pulse Load Compatibility
P
PEAK
P
0
T
PEAK
T
0
1440 W
960 W
1 s
>25 s
1440 W
0 W
1 s
>1.3 s
1200 W
480 W
1 s
>0.75 s
1440 W
480 W
0.1 s
>0.16 s
1440 W
480 W
1 s
>1.6 s
1440 W
480 W
3 s
>4.9 s
