Power Supply - Bosch FAS-420-TM-R Operation Manual

Aspiration smoke detector LSN improved
4.12

Power Supply

To measure the power supply, the detector-ready state of the security system and the alarm
case are regarded. When the system is ready to detect, the power supply must provide the
standby current for the aspirating smoke detectors and ensure the emergency power
rechargeable battery is charged in accordance with DIN VDE 0833, part 1 (80% charged in
24 hrs).
The current in the event of an alarm is calculated according to the following formula:
Calculation of current for space protection
I
g
Equipment protection
I
g
Charging current
The power for charging the rechargeable battery is calculated with the following formula:
I
L
I
=
g
where
Ig
IA
IQ
IPSmax
IL
Kn
n
nmax
Notice!
The power supply units are laid out using the calculated total current Ig with the highest
value.
Please refer to Technical specifications, page 7 for the current consumption of the FAS-420-
TM.
Line calculation
The maximum line length is derived from the permissible voltage drop on the supply line. The
permissible voltage drop is the difference between the end-point voltage of the backup
battery (21.5 V) and the lower operating voltage limits of the aspirating smoke detectors.
L
max
Bosch Sicherheitssysteme GmbH
(n _
I n I n
.
= + .
A max Q
_
I I (n
. .
= n +
A Q
0,8 K
.
n
=
24
.
I n I I
+
Q L PS max
= Total current of all connected aspirating smoke detectors in [A]
= Alarm current of an aspirating smoke detector in [A]
= Standby current of an aspirating smoke detector in [A]
= Max. power supply of the network power supply in [A]
= Charging current of the rechargeable batteries (80% of the nominal
capacity within 24 hours) in [A]
= Rated capacity of the rechargeable battery in [Ah]
= Total number of connected aspirating smoke detectors
= The highest number of aspirating smoke detectors in one detection zone
A
. .
γ
∆U
=
I . 2
g
) I
max PS max
n ) I
PS max
Operation guide
Planning | en 55
2020.04 | 5.1 | F.01U.088.878