User manual
QS3.241
Q-Series
24V, 3.4A, SINGLE PHASE INPUT
Nov. 2006 / Rev. 1.0 DS-QS3.241-EN
All parameters are specified at 24V, 3.4A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted..
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26. APPLICATION NOTES
26.1. REPETITIVE PULSE LOADING
Typically, a load current is not constant. It varies over time. For pulse load compatibility, following rules must be met:
a) The pulse power demand must be below 150% of the nominal power.
b) The duration of the pulse power must be shorter than the allowed Bonus Time. (see output section)
c) The average (R.M.S.) output current must be below the specified continuous output current.
If the R.M.S. current is higher, the unit might respond with a thermal shut-down after a while. Use the max. duty
cycle curve (Fig. 26-2) to check if the average output current is below the nominal current.
d) For altitudes higher than 2000m reduce the pulse loading (15W/1000m) or the ambient temperature (5°C/1000m)
Fig. 26-1 Repetitive pulse loads, definitions Fig. 26-2 Max. Duty Cycle Curve
100%
P
PEAK
T
PEAK
P
0
T
0
max.
150%
150%100
0
0.2
0.4
0.6
0.8
1.0
DutyCycle
110 120 130 140
P
PEAK
P
0
=
1
0
%
P
0
=
5
0
%
P
0
=
7
5
%
P
0
=
1
0
0
%
P
0
Base load (W)
P
PEAK
Pulse load (above 100%)
T
0
Duration between pulses (s)
T
PEAK
Pulse duration (s)
D
uty
C
ycle
T
0
=
T
peak
-
(D
uty
C
ycle
x T
peak
)
T
peak +
T
0
T
peak
D
uty
C
ycle
=
Utilizing the Max. Duty Cycle Curve:
Example to determine the repetition rate of pulses without dipping of the output voltage:
Parameters of application:
Pulse length is T
PEAK = 1s
Steady state load P
0=120W
(= 50% of I
RATED
)
Peak load P
PEAK = 360W
(= 150% of I
RATED
)
Determining the repetition rate:
1) make a vertical line at P
PEAK
= 150%
2) make a horizontal line where the vertical line crosses the P
0
= 50% curve
3) Read the Max. Duty Cycle from the Duty Cycle-axis (= 0.37)
4) Calculate the min. pause (base load) length T
0
:
D
uty
C
ycle
T
0
=
T
peak
-
(D
uty
C
ycle
x T
peak
)
=
0.37
1s
-
(0.37 x 1s)
=1.7s
5) Pulse length = 1s, min. pause length = 1.7s
6) Max. repetition rate = pulse length +pause length = 2.7s
More examples for pulse load compatibility:
P
PEAK
P
0
T
PEAK
T
0
P
PEAK
P
0
T
PEAK
T
0
120W 80W 1s >25s 120W 40W 0.1s >0.16s
120W 0W 1s >1.3s 120W 40W 1s >1.6s
100W 40W 1s > 0,75s 120W 40W 3s >4.9s