TITANUS
RACK·SENS
®
1U
Design
TRS_A_04-en-e
Data: 03/09
4 –
27
4.11 Power
Supply
4.11.1 Calculating capacity for external power supply
The alarm-ready status in the fire protection system and the event of an
emergency are taken into account when rating the external power supply.
The minimum supply current in the power supply unit must be calculated
in such a way that the system’s full functioning capacity is guaranteed by
the power supply unit in itself.
In case of alarm the current is calculated by the following formula:
Supply current
ing
Ch
Alarmtot
Tot
I
I
I
arg
.
.
+
=
PSU
Tot
I
I
=
.
I
Tot
=
Total current for all operating devices in [A]
I
Alarmtot
=
Alarm current in all TITANUS RACK·SENS
®
devices in [A]
I
Charging
=
Charging current for battery (within 24 hours 100% of rated
capacity)in [A]
I
PSU
=
Minimum supply current in the power supply unit in [A]
K
nominal
=
Nominal capacity of batteries in [Ah]
t
=
Required backup time in[h] (object protection 4h)
According to the table below and the selected device configuration, the
total current for an alarm indication, signal forwarding, device shutdown
according to the following formula:
Alarm
Shutdown
U
Alarm
tot
Alarm
I
n
I
I
.
1
.
.
∗
+
=
The required charging current for the batteries is calculated as follows:
Charging on current
1
K
nominal
I
charging
24
