Data Sheet

UB20.241
UB-Series
24V, 20A, DC-UPS
4. INPUT / OUTPUT
The output is connected to the input through a back-fed protection (MOSFET). In power supply mode, the output
voltage follows the input voltage decreased by a small voltage loss. In battery mode, the output voltage is a constant
voltage, which can be preselected in one of four voltages.
Input Voltage Range:
At voltages within the input voltage range, control functions such as LEDs, monitoring features, relay contacts, etc. are
functioning normally. Within the input voltage range the unit can either be in power supply mode or in battery mode.
Normal Operating Voltage Ranges (four ranges):
The normal operating voltage range describes the input voltage, which supports the full functionality of the DC-UPS
(including charging) but without entering the battery mode. It requires a minimum of 1V higher than the buffer
voltage settings and a maximum voltage of not more than 30Vdc.
Buffering and Buffer Voltage:
Buffering will start immediately without interruption after the input voltage falls below the lower end of the normal
operating voltage range. Buffering is possible even if the batteries are not fully charged.
Buffering can not be started without having previously entered the normal operating voltage range.
The buffer voltage is the output voltage determined by “the buffer voltage setting” and will not change as the
batteries discharge. The buffer voltage is pre-selectable in one of four voltages.
Fig. 4-1 Definition of “power supply mode” and “battery mode”
Battery
Mode
Output
Voltage
Input
Voltage
t
t
Transfer Threshold
Power
Supply
Mode
Power
Supply
Mode
Fig. 4-2 Input Voltage Ranges
Fig. 4-3 Buffer voltage
Settings on the front
Temporarily
allowed -
No Charging,
no Buffering
D: 26V
C: 25V
B: 24V
A: 22.5V
27V
26V
25V
23.5
V
30V30V30V30V30V
18V
35V
Buffer Voltage Settings
Four Ranges:
26V25V24V22.5V
Normal
Operating
Voltage
(4 Ranges)
Buffer
Voltage
Rated Input Voltage Range
Battery Mode
0V
DCBA
Range A
Range B
Range C
Range D
Feb. 2016 / Rev. 2.1 DS-UB20.241-EN
All parameters are specified at 24V, 20A output current, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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