SamplexPower SEC-4825BRM, Owner'S Manual

Page: 20 / 36

20 | SAMLEX AMERICA INC.
SeCtION 4 | Protections
30A will now be fed from the battery and the battery will start draining at this differen-
tial current. for example, if the overload current was 40A, the Power Supply Section will
provide 30A and the battery will provide the balance 10A. The battery will start draining
at 10A. The voltage at the Battery Terminals will start dropping and will be equal to the
voltage corresponding to its actual State of Charge. The voltage at the Load Terminals
will be around 0.3 ± 0.1V below the voltage at the Battery Terminals. External 25A fuse
(f2) on the load side will blow only on sustained current ≥ 25A, but will not blow at
higher short duration surge currents determined by its Time Current characteristics. for
example, based on the Time Current Characteristics of 80V, 25A fuse Type 166.7000.525
from Littelfuse, the fuse can pass extremely high currents for shorter durations
as follows:
- 150A for 20 ms to 100 ms.
- 88A for 40 ms to 500 ms.
- 50A for 150 ms to 20 secs.
- 28A continuous for 100 min.
In case of short circuit on the load side, the external 25A fuse (f2) on the load side will
blow because of very high additional current supplied by the battery (Additional battery
current supplied into the short circuit on the load side = Short circuit current - 30A from
the Power Supply Section). for example, if a short circuit current of 150A tries to flow for
> 100 ms, 30A will be supplied by the Power Supply Section and the balance 120A will be
supplied by the battery. As the external 25A fuse (f2) on the load side will see 150A and
the external 25A fuse (f1) on the battery side will see 120A, the external 25A load side
fuse (f2) will blow first.
PRotection AGAinSt ReVeRSe PoLARitY oF BAtteRY connection
Please ensure that the external 48V battery is connected with correct polarity.
In case of reverse polarity of battery connection, internal Diode (D3, fig 3.1) connected
across the battery terminals will be forward biased and the external 80V, 25A fuse 1
(fig 2.1) will blow.
oVeR teMPeRAtURe PRotection
!
cAUtion!
Keep the unit in a well-ventilated, cool and open area. Do NoT block the vent
holes on the sides or the discharge openings of the cooling fan at the back
of the unit.
The unit is protected against over temperature by monitoring the operation of the 2
cooling fans and heat sink temperature of one of the Power supply Modules. In case of
abnormal conditions, buzzer and LED alarm are activated locally and alarm signal is also
provided for remote signaling.