Samlex America SEC-4825BRM - Manual (Page 19)

18 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 19
Section 3 | Design & Principle of operation
sink. If the fans are operating normally but the ambient temperature of cooling air is
higher than 40°C and the unit is operating at full load, the temperature of the heat
sink will rise. When the temperature exceeds allowable threshold, buzzer alarm will
be sounded and front panel Red LED “Fan Failure” (6, Fig 2.1) will be lighted. At the
same time alarm signal will be provided for remote signaling (Pins 12 and 19 of
DB-25 Connector at the back of the unit - 12, Fig 2.1).
!
WARNING!
In both the above conditions, immediate remedial action must be taken to
ensure adequate cooling. Defective fan(s) should be replaced / availability
of cool airflow should be checked and ensured / load should be decreased.
PLEASE NOTE THAT THE UNIT WILL NOT SHUT DOWN AUTOMATICALLY AND
PROLONGED OPERATION IN THE ABOVE OVER TEMPERATURE CONDITIONS
MAY DAMAGE THE UNIT.
Section 4 | Protections
NOTE: Please refer to Figs 2.1 & 3.1, and explanation under Section 3 “Design &
Principles of Operation”.
OVER LOAD / SHORT CIRCUIT CURRENT PROTECTION
Battery Backup Function is not Used - External Battery is not Connected and
the Unit is Used as a Power Supply
In this case, the entire load current will be supplied by the Power Supply Section and will
be limited to a maximum of 30A by its Current Limit Circuitry. If the load tries to draw
a higher current than the current limit value of 30A, the output voltage at the Load
Terminals and the Battery Terminals will not be regulated and will drop below
58.5V± 0.3V. If the load impedance is further reduced, the current will remain limited at
30A but the voltage will drop further. In case of short circuit, maximum limited current
of 30A will continue to be supplied into the short circuit but the voltage will drop to
< 2V in case of a near dead short (Load impedance will be very low – say < 100 milli Ohm).
If over-load / short-circuit current of 30A continues over prolonged period, the external
25A load side Fuse (F2) will blow and will disconnect the load. If the overload / short
circuit is removed before the external 25A load side Fuse (F2) blows, the output voltage
at the Load / Battery Terminals will automatically recover when the load current drops
to less than the current limit value of 30A.
Battery Backup Function is Used - External Battery is Connected
If the load tries to draw current higher than the current limit value of 30A of the Power
Supply Section, the output voltage of the Power Supply Section will not be regulated
and the voltage at the Load Terminals will drop. Portion of overload current beyond
11001-SEC-4825BRM-0114.indd 19 14-01-07 1:15 PM