Bosch FCS‑320‑TM Series Operation Manual page 51

Conventional Aspiration smoke detector
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 FCS-320-
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
where
Lmax
A
Ig
γ
ΔU
To guarantee the impermeability of the housing, the corresponding cable bushing must be
selected for the existing cable:
–
–
Emergency power calculation
The rated capacity is calculated according to the following formula:
Kn
IQ
n
t
Ig
The factor 1.25 used in the formula is only applicable with bridging times ≤ 24 hours.
Bosch Sicherheitssysteme GmbH
= 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
= Maximum line length in [m]
= Strand cross-section in [mm²]
= Total current of all connected aspirating smoke detectors in [A]
= Conductivity: Cu=57 m/Ω mm²
= Charging current of the rechargeable batteries (80% of the nominal
capacity within 24 hours) in [A]
M 25 cable bushing: ∅ 9-14 mm
M 20 cable bushing: ∅ 8-12 mm
= Rated capacity of the backup batteries in [Ah]
= Standby current of an aspirating smoke detector in [A]
= Total number of connected aspirating smoke detectors
= Required bridging time in [hrs]
= Total current of all connected aspirating smoke detectors in [A]
Operation guide
Planning | en 51
2020.04 | 2.1 | F.01U.130.928