Datasheet

PRELIMINARY
UB20.241
U–Series
24V, 20A, DC-UPS
7. OUTPUT IN BUFFER MODE
If the input voltage falls below the transfer threshold level, the DC-UPS starts buffering without any interruption or
voltage dips. Buffering is possible even if the battery is not fully charged.
Output voltage in buffer mode
22,5V, 24V,
25V, 26V
Output voltage is adjustable, stabilized and independent
from battery voltage
Ripple and noise voltage
max 120mVpp. 20Hz to 20MHz, 50Ohm
Output current nom. 20A Continuously allowed at 22.5V output voltage *)
30A <4s with full output voltage at 22.5V output voltage
Short-circuit current typ. 31A Load impedance 50mOhm
*) Derating of the output current is necessary at higher output voltage. See Fig.: 7-1
BonusPower®, short term power capability (up to typ. 4s)
The UPS is designed to support loads with a higher short-term power requirement without damage or shutdown. The
short-term duration is hardware controlled by an output power manager. This BonusPower® is repeatedly available.
If the UPS is loaded longer with the BonusPower® than shown in the Bonus-time diagram (see Fig. 7-2), the max
output current is automatically reduced to 20A.
If the current requirement is continuously above 30A and the voltage falls below approx. 20V (due to the current
regulating mode at overload), the unit shuts-off and makes periodical restart attempts. This behaviour is called
hiccup mode which is described below. If the voltage is above 18V, the unit continuously delivers current.
Hiccup Mode:
Up to 4s of overloading, the UPS delivers continuous output current. After this, the output power is reduced to nearly
zero for approx. 17s before a new start attempt is automatically performed. If the overload has been cleared, the
device will operate normally. If the overload still exists, the output current will be delivered for 2 to 4s (depending on
the overload) again followed by a 17s rest time. This cycle is repeated as long as the overload exists. See Fig. 7-3.
During the off-period a small rest voltage and rest current is present on the output.
Output current
nom. 30A at 22.5V, see Fig. 7-1
Short-circuit current min. 31A load impedance 50mOhm, up to 4s, see Fig. 7-1
Bonus time typ. 4s duration until the output voltage dips, see Fig. 7-2
min 3.5s
max 4.5s
Fig. 7-1 Output voltage vs. output current, typ. Fig. 7-2 Bonus time vs. output power
Output Voltage
Output current
0
048 1620
4
8
12
16
20
32A12 24 28
28V
22.5V
26V
Hiccup
mode
continous
for 4s
24V
25V
Bonus Time
0
110 120 130 140 150
160%
Output Power
1
2
3
7
4
5
6
8
9
10s
m
i
n
m
a
x
typ
September 2012 / Rev. 1.3 DS-UB20.241-EN preliminary
All parameters are specified at an input voltage of 24V, 20A output load, 25°C ambient and after a 5 minutes run-in time
unless otherwise noted. It is assumed that the input power source can deliver a sufficient output current.
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