18 | SAMLEX AMERICA INC.
SeCtION 3 |
Design & Principle of Operation
10. Replace the top cover. Power on the unit and confirm that the “PSM Status”
LEDs of all the installed modules are lighted.
Bypassing Defective Module - (Pending Replacement with new Module)
Assume one of the 5 modules is defective and a new replacement module is not avail-
able. In this case, the defective module can be bypassed. As only 4 modules will be
sharing the current, only 20A will be available. Assuming battery-charging current of
maximum 2A, the load current should be limited to < 18A.
1. Switch off 120VAC, 60 Hz input power and unplug the power cord from the
main outlet.
2. Remove the top cover plate by unscrewing the 10 screws.
3. Remove the AC input power supply wires from terminals “L” and “N” of the
defective module (fig 3.4). Insulate temporarily with insulation tape.
4. Remove connectors from terminals “LED 1 & LED 2” (fig 3.4).
5. Remove female connector of the Daisy Chained “SHARE BUS” wire loop connected
to male terminal “JUMP1” on the module (fig 3.4, fig 3.5).
6. It is mandatory to short the two female sockets on this unused female connector with
a shorting link. (See fig. 3.6). This will ensure that there is no break in the “Share
Bus” Daisy Chain and that all the “Jump1” terminals are interconnected.
7. It is necessary to ensure that the voltages of the 4 remaining active individual paral-
leled modules are set exactly at 55V. for this, follow instructions given under “Proce-
dure for Adjusting output Voltage of Modules” (page 16).
8. Replace the top cover. Power on the unit and confirm that the “PSM Status” LEDs for
the 4 modules are lighted.
cooLinG
Due to modular design, each Power Supply Module has its own heat sink that is
mounted on its PCB. As these heat sinks are not thermally connected to the metal chas-
sis of the unit, cooling by convection through the surface area of the metal chassis is
not adequate. Hence, 2 fans (running all the time) are used for cooling of the modules.
These fans suck cool air from the ventilation slots on the sides and discharge through
the fan openings at the back (9, fig 2.1).
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. Details are given below:
• In case any one of the 2 fans fails (open circuit, short circuit, low RPM), 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)
• One of the Power supply Modules has a Temperature Sensor mounted on its heat
Summary of Contents for SEC-4825BRM
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