User manual
QS10.121
Q-Series
12V, 15A, SINGLE PHASE INPUT
October 2006 / Rev. 1.0 DS-QS10.121-EN / All parameters are specified at 12V, 15A, 230Vac and 25°C ambient unless otherwise noted.
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27. APPLICATION NOTES
27.1. 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 will respond with a thermal shut-down after a while. Use the max. duty
cycle curve (Fig. 27-2) 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. 27-1 Repetitive pulse loads, definitions Fig. 27-2 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
270W 180W 1s >25s 270W 90W 0.1s >0.16s
270W 0W 1s >1.3s 270W 90W 1s >1.6s
225W 90W 1s > 0,75s 270W 90W 3s >4.9s