Samlexpower SEC-2430BRM User manual

N + 1 DC Power
System
SEC-2430BRM
SEC-2440BRM
SEC-2450BRM
Please read this
manual BEFORE
installing your
N + 1 DC Power
System
Owner's
Manual

2 | SAMLEX AMERICA INC.
OWNER'S MANUAL | Index
SECTION 1
Important Safety Instructions ................................................ 4
SECTION 2
Description & Application .................................................... 6
SECTION 3
Design & Principle of Operation ........................................... 6
SECTION 4
Cooling & Warning for Fan Failure ....................................... 7
SECTION 5
Front Panel Controls & Indicators ......................................... 8
SECTION 6
Rear Panel Controls .............................................................. 8
SECTION 7
Protections ......................................................................... 10
SECTION 8
Installation & Operation ..................................................... 10
SECTION 9
Operation of Battery Backup ...............................................11
SECTION 10
Output Voltage Adjustment ............................................... 13
SECTION 11
Installation & Removal of Modules ..................................... 15
SECTION 12
Troubleshooting ................................................................. 17

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SECTION 13
Limiting Electromagnetic Interference ................................ 18
SECTION 14
Specications ..................................................................... 20
SECTION 15
Appendix: Figures 1 to 3 .................................................... 21
SECTION 16
Warranty ......................................................................... 23

4 | SAMLEX AMERICA INC.
SECTION 1 | Important Safety Instructions
The following safety symbols will be used in this manual to highlight safety
and information:
WARNING!
Indicates possibility of physical harm to the user in case of non-compliance.
!
CAUTION!
Indicates possibility of damage to the equipment in case of non-compliance.
i
INFO
Indicates useful supplemental information.
Please read these instructions before installing or operating the unit to prevent personal
injury or damage to the unit.
!
CAUTION!
ALL ELECTRICAL INSTALLATIONS MUST MEET LOCAL AND NATIONAL WIRING
CODES AND SHOULD BE PERFORMED BY A QUALIFIED ELECTRICIAN.
Operation Of Cooling Fan
The heat produced is extracted by 2 fans. In case any of the fans fail, light and sound
alarms will be activated. Immediately SWITCH OFF the power to the unit to prevent
damage due to over heating.
Connection To AC Outlet
The power supply should be operated only from a standard 3 pin 120 VAC, 60 Hz outlet
with proper grounding connection.
SEC-2450BRM must be powered from a 30A branch circuit and should be plugged into
a 30A AC receptacle which will accept the 30A NEMA-L5-30P plug of the power cord.
SEC-2440BRM must be powered from a 20A circuit and must be plugged in to a 20A AC
outlet which will accept the 20A NEMA 5-20P plug provided with the power cord. SEC-
2430BRM may be powered from a 15A circuit. Although SEC-2430BRM is provided with
20A, NEMA 5-20P plug, this may be powered from a 15A branch circuit if 20A branch
circuit is not available. For this situation, a separate 15A, NEMA 5 -15P plug has been
provided to replace the 20A, NEMA 5-20P plug provided with the power cord.

4 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 5
SECTION 1 | Important Safety Instructions
!
CAUTION!
Replacement should be done by a qualied electrician. Please ensure proper
polarity of the connections as follows :
“ L ” LINE ................................................ BROWN
“ N ” NEUTRAL ....................................... BLUE
EARTH GROUND..................................... GREEN WITH YELLOW STRIPE
Do not use extension cord unless absolutely necessary. If an extension cord must be
used, make sure:
1. The pins on the extension cord's plug are of the same number, size and shape as those
of the plug of the power supply cord. Never use an extension cord with a 2 pin plug
(there will be no grounding connection in this type of plug, which is a shock and re
hazard).
2. The extension cord should be a minimum 12 AWG, 20A.
Load And Battery Connections
The load & battery terminals on the power supply have a tubular hole of diameter 8mm
(0.31”) with a set screw.
Always ensure that the connections are secure and the screws are tightened properly.
Loosely tightened connections result in excessive voltage drop and may cause over-
heated wires and melted insulation.
The ends of the cables to be connected to the load and battery terminals on the power
supply should have pin type of connector for making a rm conncecton. 4 Pieces of pin
type connectors are enclosed with the power supply. Crimp these to the ends of the
cables.
Use multi stranded welding type cable or battery cable (neoprene synthetic insulation,
90˚C / 194˚F). Use proper size of cable, as indicated below, to connect any device to the
power supply. These cable sizes are valid when the device is within 6 ft. Distance from
the power supply. Thicker wiring will be required for longer distances. Thinner wires
will cause overheating and excessive voltage drop:
MODEL AMPS WIRE TYPE (UP TO 6' DISTANCE)
SEC-2450BRM 50A AWG # 4
SEC-2440BRM 40A AWG # 6
SEC-2430BRM 30A AWG # 8
Ensure that the AC power is switched OFF when any device is being connected to the
power supply.
DO NOT ALLOW the ends of the Positive and Negative wires to touch each other.

6 | SAMLEX AMERICA INC.
SECTION 2 | Description & Applications
Fuse Replacement
Ensure properly rated fuse (250V, 4A) is used in each of the modules.
Environment
DO NOT expose power supply to rain, snow or water spray
Dis-assembly And Repair
The power supply should be disassembled or repaired by a qualied technician. Incor-
rect reassembly or repair may result in a risk of electric shock or re which may result in
personal injury and property damage.
Description
This is a 19", 2U height (3.5”) Rack mount power supply which converts 120V,
60 Hz AC power into regulated 28 VDC , +/- 1% (at module output*) delivering up to a
maximum of 50A continuous (up to 57.5A surge) with 5 base level PCB modules. There
is provision to connect the power supply to an external battery for backup power in the
case of an AC power failure and re-charge the battery when AC power resumes.
* Voltage at output terminals load + & load - will be 27.6V nominal
Applications
The unit is designed for the following applications:
1. N+1 redundant systems
2. Future power level expansion
3. Un-interrupted DC output when used in conjunction with an external battery backup.
SECTION 3 | Design & Principle of Operation
The unit is designed using advanced switch-mode technology and active load share cir-
cuitry for high reliability, high efciency and minimum size and weight. It is modular in
construction consisting of up to 5 base level PCB modules (referred to as “PSM” – power
supply module) that are connected in parallel with true current sharing. Each PSM is a
stand alone power supply which delivers up to a maximum of 10A continuous. By equal-
izing the output currents, uniform thermal stress of the individual PSM is ensured which
has utmost importance for long term reliability of electronic components. The operat-
ing principle of the current share mechanism is to measure the output current of each
PSM and to be able to modify the output voltages of the PSMs until all the participating

6 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 7
SECTION 3 | Design & Principle of Operation
PSMs deliver equal output current. Typically, the output currents of the paralleled PSMs
will be within 10% of each other at full output current. One of the modules automati-
cally assumes the role of a master and the others operate as slaves. Each PSM is required
to be interconnected with one another to a common “SHARE BUS” through a pair of
parallel pins marked “Jump 1” and jumper wires ( Fig.1 and 2).
For proper operation of the current share control circuitry, a minimum load current is
required to ow through each PSM to produce adequate feed back signal. This mini-
mum pre-load current is provided by the sum of the currents drawn by the fans and by
an internal static load resistor connected across the load output terminals. This internal
pre-load current* is kept to the minimum to reduce dissipation.
NOTE:
It is likely that due to the drift in the pre-set values, the minimum internal preload
current may not be sufcient to provide adequate feedback signal strength resulting
in shut down of one or more modules when no external load is present (the associated
PSM status LED will ash and also, the associated signal for remote indication will oscil-
late between high and low). As soon as external load is applied to the unit, the feed
back signal strength will increase and the PSM(s) that were shut down will also operate
normally.
The output is delivered through an isolating Schottky Diode to enable connection of
external battery for un-interrupted DC power output. The external backup battery is
kept charged by taper charging through a series resistor.
• SEC-2450BRM has 5 PSMs of 10A each providing a total of 50A
• SEC-2440BRM has 4 PSMs of 10A each providing a total of 40A
• SEC-2430BRM has 3 PSMs of 10A each providing a total of 30A
SECTION 4 | Cooling & Warning for Fan Failure
The heat generated due to internal power dissipation is removed by forced cooling
through two high power D.C. Fans mounted at the back of the unit which suck air from
the vents on the sides of the unit & blow outwards from the rear of the unit. It is
extremely important that the discharge side of the fans and the suction sides of the
vent slots are not blocked.
A warning circuit monitors the operational condition of the fans. In case of a fan failure,
a buzzer will sound and the red LED indicating “FAN FAILURE” will light up. The unit
should be switched OFF immediately and the defective fan should be replaced. Never
load the unit when there is an audible alarm and the fan failure LED is illuminated.
The 2 fans are rated for 24V nominal and are powered from the output voltage of the
modules. A small printed circuit board (PCB) located on the right corner towards the
back of the unit is used to monitor the fans for abnormal operating conditions viz. open
circuit or overload condition due to obstructed rotor.

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The following controls and indicators are provided on the front panel :
1. A. Power ON/OFF Switch – The rocker switch will illuminate when switched ON.
B. Breaker – A 25A circuit breaker provides protection on the input side against overload.
2. Voltmeter / ammeter – A combined voltmeter and ammeter are provided. The
function can be switched by the volt / amp switch (3).
3. Meter Change-over Switch – Switches the combined meter between ammeter and
voltmeter
4. L.E.D “ PSM Status (1 to 5)” – During normal operation, the green LED of each power
supply module (PSM) will light. In case a power supply module (PSM) fails, its corre-
sponding LED will go OFF. LED 1 is for the left most module (near the ON/OFF switch)
5. L.E.D “Fan Failure ” – in case of fan failure, this red LED lights up and a buzzer is
sounded.
ONOFF
PSM STATUS FAN FAILURE
METER
VOLT AMP
N + 1 DC POWER SYSTEM
www.samlexamerica.com
LOAD - LOAD + BATTERY - BATTERY+
627-2011_SEC40BRM_BACK
1A 1B 4 5 2
3
SECTION 6 | Rear Panel Connectors
The following output connectors have been provided (not shown).
1. Load+ (Positive), Load- (Negative) Load Connectors – For connecting to the D.C. load.
2. Battery+ (Positive), Battery- (Negative) Battery Connectors – For connecting external
battery for un-interrupted D.C. Power to the load.
SECTION 5 | Front Panel Controls & Indicators

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SECTION 6 | Rear Panel Connectors
Remote Monitoring And Signalling
A provision has been made for remote signaling and monitoring of the following
operational conditions and parameters:
1. Operational status of the 5 power supply modules (PSM)
2. Failure condition of the cooling fan(s)
3. Availability of AC input power
4. Output voltage measurement
5. Output current measurement (voltage across an internal shunt with shunt ratio
of 25 mv / 50A or 0.5 Mv per amp)
Signaling of operational conditions as at serials 1, 2 and 3 above is opto coupled with
open collector, NPN transistor outputs. The collector and emitter of each opto coupled
transistor are accessible to the external user interface through the 25 pin d-sub connec-
tor. Each open collector, opto coupled NPN transistor can provide a maximum of
50 mA with a collector to emitter voltage of up to 35V.
Outputs for voltage and current measurements at serials 4 & 5 above are direct ana-
logue voltages. The pin out of the 25 pin d-sub connector providing the above signals
for user interface is given below:
Note: this signal is the voltage across an internal shunt at 0.5 Mv per amp
(shunt ratio is 25 Mv / 50A).
ITEM PIN NO. COLOR CODE
OF WIRE
OPTO-COUPLER
OUTPUT PIN
OPERATIONAL
CONDITION OR
PARAMETER (HIGH)
12Black Collector AC input is available
16 White Emitter
212 Orange Collector Fan failure
19 Green Emitter
37Gray Collector PSM 1 Normal
20 Violet Emitter
48Violet Collector PSM 2 Normal
21 Blue Emitter
59Blue Collector PSM 3 Normal
22 Green Emitter
610 Green Collector PSM 4 Normal
23 Yellow Emitter
711 Yellow Collector PSM 5 Normal
24 Orange Emitter
825 Red -Voltmeter +
13 Black -Voltmeter -
918 Gray -* Ammeter +
6Blue -* Ammeter -

10 | SAMLEX AMERICA INC.
SECTION 7 | Protections
Protections
Short Circuit Protection: In the event of a short circuit, the PWM controller will be shut
down and the output will drop to near 0V. The green LEDs will ash. The unit will reset
automatically once the short circuit condition is removed.
Current Limiting: The unit will enter this mode when the load tries to draw more than
the limiting values of currents as shown in the specications. Under this condition, there
will be loss of voltage regulation and the output voltage will drop. The “PSM Status”
LEDs will, however, remain illuminated, but dimmed. When the overload reaches
approximately 70Afor SEC-2450BRM or 56A for SEC-2440BRM or 42A for SEC-2430BRM
(the output voltage will be approximately 5.4V), the unit will shut down (will enter
hiccup mode). The PSM status LEDs will start ashing and PSM status signal for remote
indication will oscillate between high and low. The unit will reset automatically as soon
as the overload condition is removed .
Input Surge Protection: The unit is protected against input voltage surges. In case of
input Spike/Surge, the A.C. Side breaker will trip. The 4Afuse on the module will also
blow.
Fan Failure Warning Indicator And Alarm: If forced air cooling is stopped due to failure
of any one or both the fans, the RED “FAN FAILURE“ LED will be illuminated and an
alarm buzzer will be activated. At the same time, a “high” signal will be fed to the opto-
coupler for signaling “fan failure” for remote monitoring. The unit is required to be
switched OFF immediately as loss of forced air cooling may result in major damage to
the unit.
SECTION 8 | Installation & Operation
1. Ensure that the space where the unit is to be installed has adequate air supply for
cooling. There should be no obstruction on the suction vent slots on the sides of the
unit or on the discharge side grilles of the fans on the back of the unit.
2. Switch OFF the ON/OFF switch on the front panel.
3. Switch OFF all the D.C. Load(s) to be connected to this unit.
4. Connect the load+ and load- at the back of the unit to the D.C. Load(s) or the
DC bus.
Ensure the wire or bus bar used to connect the load or the D.C. Bus is of proper
cross-section to carry the desired load current. Tighten the screws to ensure rm
connection.
5. In case external battery is required for battery back-up, connect the Positive of the
battery to battery + and Negative of the battery to battery -. (See details under “
Operation Of The Battery Back-Up”)
6. Plug the unit into the 120V, 60Hz standard AC outlet. The outlet should be rated at
30A for SEC-2450BRM, 20A for SEC-2440BRM & 20/15A for SEC-2430BRM.

10 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 11
SECTION 8 | Installation & Operation
7. Switch ON the unit by pressing the power ON/OFF switch to ON position. The switch
will be illuminated conrming that input power is available.
8. A short beep may be generated by the temperature fault alarm circuit on powering
ON the unit . This is normal, please disregard.
9. The PSM Status LEDs will light and “ON” signal will be fed to the associated drives of
the opto-couplers for remote monitoring / indication through the 25 pin d-sub con-
nector. As explained under design & principle of operation, a minimum load current
is necessary to operate the current share control circuitry of the PSMs. It is likely that
due to the drift in the pre-set values, the minimum internal preload current may not
be sufcient to provide adequate feedback signal strength resulting in shut down
of one or more modules when no external load is present (the associated PSM status
LED will ash and also, the associated signal for driving the opto couplers for remote
indication will oscillate between “ON” and “OFF” conditions). As soon as external
load is applied to the unit, the feed-back signal strength will increase and the PSM(s)
that were shut down will also operate normally.
10. Switch the volt/amp change-over switch to the “VOLT” position. The voltmeter
should read 27.8V on no load.
11. Switch on the D.C. Loads. The output voltage on load should be 27.5V to 27.4V.
12. Switch the volt/amp meter switch to “AMP” position to read the load current. Ensure
that the load current is within the total rated continuous load of the modules installed.
SECTION 9 | Operation of Battery Back-up
WARNING!
The battery should be located in a well ventilated area to safely dissipate
hydrogen gas produced during the charging process.
ATTENTION!
La batterie doit être située dans une zone bien ventilée pour dissiper en toute
sécurité le gaz hydrogène produit pendant le processus de charge.
Please refer to the schematic at Fig. A.
Regulated output voltage of 28VDC +/ - 1% from the modules ( measured at screw
terminals S5 and S6, (Fig.1) is fed to the Positive and Negative DC bus bars and from
there to the output terminals load+ and load- through the isolating Schottky Diode
D1. Although the output voltage at the module terminals S5 and S6 (Fig.1) or at the
common DC bus bar (before the Schottky Diode D1) is tightly regulated at the preset
value of 28VDC +/ - 1%, the voltage at the output terminals load + and load - will vary
slightly due to the forward voltage drop of the isolating Schottky Diode D1 and the
drop along the DC bus bar and wiring.

12 | SAMLEX AMERICA INC.
The voltage at the output terminals load + and load – will be as follows :
At no external load approx. 27.8V
At 10A load approx. 27.6V
At loads > 10A approx. 27.6V minus 5mv per amp above 10A
When there is a requirement of un-interrupted D.C. Power to the load, an external
battery may be connected at the terminals battery + and battery –. When the input A.C.
Power is available, the load current is supplied by the power supply through isolating
Schottky Diode D1. At the same time, the battery is charged through resistors R1 & R2.
(These resistors will limit the maximum charging current to about 8 Amperes.)
If the input A.C. Power is interrupted, the external battery feeds the load instantane-
ously through the Schottky Diode D2 (D2 will by-pass the resistors R1 & R2). Voltage
available to the load will be approximately 0.4V lower than the battery voltage due to
forward voltage drop across D2.
WARNING
The battery should be located in a well ventilated area to safely dissipate hydrogen gas
produced during the charging process.
ATTENTION!
La batterie doit être située dans une zone bien ventilée pour dissiper en toute
sécurité le gaz hydrogène produit pendant le processus de charge.
SECTION 9 | Operation of Battery Back-up
R1
R2
D2D1
NEGATIVE BUS BAR
POSITIVE BUS BAR
Battery -
Battery +
Load +
Load -
R
LEGEND
D1, D2 Schottky Diode: 30V, 210A
R1, R2 Power Resistor: 0.78 OHM, 35W
R Static Load Resistor: 200 OHM, 5W
(3 x 70A Diodes in parallel)
(3 x 70A Diodes
in parallel)
Figure A

12 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 13
Availability of AC power is signaled for remote monitoring through an opto-coupled
signal through the d-sub connector (see page 9 under “Remote Monitoring & SignalI-
ing”). This signal may also be used to indicate that the load is being powered by battery
(in case external battery is used for battery back-up).
When the input AC power returns, the battery will be isolated and the load current
will once again be supplied by the power supply. The discharged battery will recharge
through R1 & R2 (R1 & R2 are in parallel offering a net resistance of 0.73 Ohm).
NOTE: The value of charge limiting resistors is based on a typical 100AH deep cycle ma-
rine battery. If a different type of battery is used, the value of the resistor should
Be adjusted to meet associated charging requirements.
SECTION 10 | Output Voltage Adjustment
NOTE: The voltages indicated are at no load and are measured at any of the module
output pads under S5 and S6 or at the DC bus before the Schottky Diode D1.
Parallel Operation Under Forced Current Share Control
The output voltage of each module measured at the module output pads under S-5
AND S-6 (see Fig.1) Is factory pre-set at 28V. A precision multi turn potentiometer VR1 is
provided for ne adjustment of the output voltage of the module (The adjustment range
is 26.8V to 28.5V ).
For the forced current share control to work properly, it is important that the output
voltage of each module connected in parallel is exactly the same. When 2 or more
modules are operating in parallel under forced current share control and if the output
voltage of any module is below 28V, it’s current share control circuitry will not function
properly and it’s LED will start ashing. The LEDs of the other modules which are put-
ting out 28V will remain continuously lighted and the output voltage of the common
DC bus (before the Schottky Diode D1) will be 28V.
If the output voltage of any module is higher than 28V, it’s LED will remain continu- ous-
ly lighted but the LEDs of all the other modules will ash randomly. The output
voltage of the common DC bus (before the Schottky Diodes D1) will read the higher
voltage of this module.
Adjusting The Output Voltage Of The Modules At No Load
NOTE: The output voltage is adjusted by multi turn potentiometer VR1 ( Fig.1). As the
adjustment is very ne, multiple turns will be required even for small voltage change.
Turn clockwise for decreasing and anti-clockwise for increasing. The adjustment range is
26.8V to 28.5V.
As explained under "Operation Of Battery Back up", although the output voltage at the
module terminals S5 and S6 (Fig.1), or at the common DC bus (before the Schottky Di-
SECTION 9 | Operation of Battery Back-up

14 | SAMLEX AMERICA INC.
SECTION 10 | Output Voltage Adjustment
ode D1) is tightly regulated at the preset value of 28V +/-1%, The voltage at the output
terminals load + and load - will vary between 27.8V at no load to 27.45V at full load of
50A due to the forward voltage drop of the isolating Schottky Diodes D1 and the drop
along the DC bus and wiring.
The output voltage of the paralleled modules or the common DC bus (before the
Schottky Diodes D1) can be adjusted between 26.8V and 28.5V by adjusting the voltage
of each module individually as per the following procedure (this procedure is explained
for SEC-2450BRM, which has 5 modules).
The voltage at the output terminals load + and load – will be as follows :
AT NO EXTERNAL LOAD Module voltage minus 0.2V
AT 10A LOAD Module voltage minus 0.4V
AT LOADS > 10A Module voltage minus 0.4V minus 5mv per amp above 10A
Procedure
• Switch OFF the unit and unplug the power cord.
• The output voltage of each individual power supply module (PSM) is adjusted one
by one starting from the left most module – PSM 1 and progressing to the right most
module – PSM No. 5 (for SEC-2450BRM). AC input is connected only to the module
being adjusted. AC input to the remaining modules is disconnected.
• Remove the AC input connections (female quick connect terminals connected to the
l and Nmale tab terminals on the modules – Fig. 1) From PSM nos. 2, 3, 4 And 5.
Temporarily insulate these female quick connect terminals with insulating tape for
safety. Now, only PSM No. 1 can be energized.
• Switch ON the power supply. Only PSM No. 1 will operate. Adjust the output voltage
of this module to the desired value with the help of potentiometer VR1 (Fig.1) Meas-
ure the voltage at the screw terminals S5 and S6 (Fig.1)
• Switch OFF the power supply. Remove the AC input connection from PSM No. 1. Tem-
porarily insulate these terminals with insulation tape. Remove temporary insulation
from the AC connectors for PSM 2 and connect them to PSM 2. Now only PSM 2 can
energize.
• Switch ON the power supply. Only PSM No. 2 will operate. Adjust the output voltage
of this module to the desired value with the help of potentiometer VR1 (Fig.1). Meas-
ure the voltage at the screw terminals S5 and S6 (Fig.1)
• Continue to adjust the voltage of the remaining Module Nos. 3, 4 and 5 individually
as explained above making sure that the AC power is connected to only the module
being adjusted.
• After all the modules have been adjusted to the same output voltage, connect the AC
input back to all the ve modules.
• Power on the unit and check that all the 5 “PSM Status” LEDs are lighted. This will
conrm that the voltage adjustment has been completed successfully.

14 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 15
SECTION 11 | Installation & Removal of Modules
NOTE: as explained under design & principle of operation, it is likely that the minimum
internal preload current for the new value of the output voltage may not be sufcient
to provide adequate feedback signal strength resulting in shut down of one or more
PSM(s) when no external load is present (the associated PSM status LED will ash and
also, the associated signal for remote indication will oscillate between high and low). In
such a case, apply an external load to increase the feed back signal strength. If there is
no other defect, the PSM(s) that were shut down will also operate normally.
Installation and Removal of Power Supply Modules
i
INFO
NOTE: installation and removal of power supply modules should be performed
only by qualied personnel.
!
CAUTION!
Before removing a defective module or installing a new one, switch OFF the 120V,
60HZ input power and unplug the power cord from the mains outlet. Please refer
to the layout diagram of the module at Figure 1.
Upgrading To Higher Capacity – Installing Additional Module(s)
Additional optional module(s) (Model No. SEC-1024MPSB) can be added to upgrade the
output current capacity of SEC-2430BRM / SEC-2440BRM by steps of 10Ato a maximum of
50A. For example, SEC-2430BRM (30A) can be upgraded to SEC-2440BRM (40A) by adding
1 additional optional 10A module (SEC-1024MPSB) or to SEC-2450BRM (50A) by adding 2
additional optional 10A modules (SEC-1024MPSB).
The optional module SEC-1024MPSB comes with an LED and LED holder. It’s output
voltage is pre-set at 28 Volts.
The procedure to install additional module(s) is as follows:
1. Remove the top cover plate by unscrewing the 10 screws.
2. Each module sits on 6 stand-offs under the holes S1 to S6 (Fig.1). Additional module(s)
are to be installed in the vacant space(s) adjacent to the right of the existing module.
Remove the screws from the 6 stand-offs for the adjacent vacant space for the module.
3. Place the module on the stand-offs with the l an Nterminals (Fig.1) Towards the front
panel. Align the holes and x the module with the 6 screws. WARNING! Please ensure
that screws S5 and S6 are very tight as the pads under these two screws connect the
output of the module(s) to the DC bus bar underneath. A loose connection under these
screws will result in sparking , overheating and consequent damage to the module.
4. Each module has independent AC power input wires. Locate unused pair of AC input
wires. (Black and White with insulated female quick connect terminals). The black wire
is required to be connected to the male tab terminal marked l (Fig.1) And white wire
is required to be connected to the male tab terminal marked N(Fig.1). Do not connect
these wires till step 8 below.

16 | SAMLEX AMERICA INC.
SECTION 11 | Installation & Removal of Modules
5. Terminal marked LED 2 (Fig.1) is used for the front panel LED under “PSM Status (1 to 5)”
and terminal marked LED 1 (Fig.1) is used for remote indication through the d-sub con-
nector. The PSM status output signal from connector LED 1 is fed to the associated opto-
coupler on the small opto-coupler PCB (printed circuit board) & from there it is fed to the
d-sub connector. Connection to the opto-coupler PCB and onward to the d-sub connector
for remote indication is made using color coded pair of wires for each of the 5 modules
(please see the colour code for PSM 1 to 5 under remote monitoring and indication on
page 5). An LED holder and a green LED with wire and female quick connect terminal
are provided with the new module for connecting to the front panel. The vacant hole(s)
for the front panel LEDs are closed with plastic plug(s). Remove the plastic plug from the
vacant hole for the LED under the existing bottom most LED. Insert the LED holder in
this hole from the outside. Insert the green LED from the inside and push it till it locks.
Connect the female quick connect terminal of the LED to the male quick connect terminal
marked LED 2 (Fig.1). If remote indication is also required, then connect the female quick
connect terminal of the corresponding colour coded wire for the remote indication con-
nection to the male quick connect terminal marked LED 1 (Fig.1).
6. All the connected modules operate under forced current share control through a daisy
chained share bus formed by interconnecting each module through the male quick con-
nect terminal marked Jump 1 (Fig.1 & 2). A wire with 5 female quick connect terminals is
provided for the above connection. Locate the unused female quick connect terminal(s)
of this wire and connect it to the male quick connect terminal marked Jump 1 (Fig.1).
7. Use cable ties to secure all loose wiring.
8. As explained under “Output Voltage Adjustment”, the output voltage at the individual
modules (measured at points S5 & S6 of the module as shown at Fig. 1) is required to be
set exactly at the same voltage for proper current share control. Each module is factory
preset at a voltage of 28V with the help of potentiometer VR1. Although the optional
module SEC-2012MPSB is factory preset at 28V, it may differ slightly due to tolerance. It
is, therefore, necessary to ensure that the voltage of all the individual paralleled modules
{the existing modules and the additional optional module(s)} is set exactly at 28V. For this,
follow instructions given under “procedure” on page 14.
9. Replace the top cover. Power on the unit and conrm that the “PSM status” LEDs of all
the installed modules are lighted.
Removing A Defective Module
1. Remove the top cover plate by unscrewing the 10 screws.
2. Locate the defective module. Remove the 6 screws from S1 to S6.
3. Remove the input power supply wires from terminals “l” and “n”. Insulate the wire
terminals with insulating tape.
4. Remove connectors from terminals “LED 1 & LED 2” .
5. Remove the “share bus” wire female socket connector from the terminal “Jump
1” and if the defective module is not being replaced immediately and if the unit is
required to be operated without this defective module.
It is mandatory to short the two female sockets on this unused female connector
with a shorting link. (See Fig. 3 ) This will ensure that there is no break in the “share
bus” daisy chain and that all the “Jump 1” terminals are interconnected.
6. The module can now be removed.

16 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 17
POWER ON/OFF SWITCH DOES NOT LIGHT WHEN SWITCHED ON
-Check that power is available in the AC outlet.
- Check that the power cord plug is properly plugged in.
BREAKER TRIPS
The breaker has tripped due to abnormal condition. Call technical support.
“FAN FAILURE” LED LIGHTS UP AND BUZZER IS SOUNDED
- One or both of the fans have stopped.
- Forced cooling has failed due to defect in the cooling fan(s)
- Switch OFF the unit immediately. Fan(s) needs to be replaced. DO NOT USE THE UNIT TILL THE
DEFECT IS RECTIFIED. IT IS PROHIBITED TO USE THE UNIT WITHOUT FORCED COOLING. CALL
TECHNICAL SUPPORT.
- If both the fans are running, the small fan status monitoring PCB may be defective.
Call technical support.
“ PSM STATUS ” LED(S) DOES NOT LIGHT UP
The associated module has become defective. The unit will still operate normally as the remain-
ing working modules will share a higher load. The unit will go into current limit and the output
voltage will drop if the load drawn is more than the combined maximum rated output of the
remaining modules. Reduce the load so that the maximum load drawn is less than the combined
maximum rated output of the working modules.
Remove the defective module and replace with a new module.
OUTPUT VOLTAGE DROPS ON LOAD
The unit has gone into current limit as the load being drawn is more than the combined maximum
rating of the working modules. This may also result if one or more modules has failed . Check that
all the modules are operating properly. If a module has failed, its green LED would extinguish or
ash. Reduce the load drawn to a value less than the combined maximum rated output of the
working modules. If the voltage does not rise to the rated voltage of 27.5V to 27.4V, then switch
OFF all the loads. If the voltage in this condition is also low, switch off the unit and contact techni-
cal support.
ONE OR MORE “PSM STATUS” LED(S) FLASHES
- The output voltage of the individual modules is not the same or the forced shared control
circuitry of the module(s) is defective. Adjust the voltages of the modules to 28V.
- If the problem still exists, contact technical support.
- If the one or more PSM status LED(s) ash when no external load is connected, it may mean that
the internal pre-load current is not sufcient to provide adequate feedback signal for the cur-
rent share control circuitry. Apply external load. If the ashing stops, the associated PSM(s) are
normal. If ashing continues even after applying an external load, contact technical support.
SECTION 12 | Troubleshooting

18 | SAMLEX AMERICA INC.
1. Switched mode power supplies (SMPS) employ high frequency switching and thus, are
a source of radio interference, a recipient of radio interference and a conduit of radio
interference (older linear type transformer based power supplies do not employ high
frequency switching voltages and will be quieter as compared to switching type of
supplies ).
2. The primary emission sources originate in the switching devices due to their fast
switching current transitions: harmonics of the switching frequency and broadband
noise created by under-damped oscillations in the switching circuit. The secondary
source is from the bridge rectier, both rectier noise and diode recovery. The AC
input rectier / capacitor in the front end of the switching power supplies (except-
ing those with power factor correction) are notorious for generating power supply
harmonics due to the non linear input current waveform. The noise is both conducted
and radiated through the Input power cord and the DC output wiring to the radio.
Filters are used to limit the noise to acceptable level.
3. Switching power supplies are also recipients of radio interference. The normal op-
eration of the power supply can be disturbed due to RF noise getting coupled into
the power supply. Thus, the power supply may generate excessive RF noise and lose
output voltage regulation due to excessive transmitter energy being coupled through
the AC/DC lines to the power supply’s regulator feedback path. This may be due to
antenna being too close or due to the antenna or feed system not radiating properly.
First check the antenna system SWR. Then, if necessary, relocate either the antenna or
the power supply farther apart.
4. The receiver may “hear” the power supply. A slowly moving, slightly buzzing carrier
heard in the receiver may be caused by the antenna being too close. As with the
transmitter related noise pick up, a loose coaxial connector or a broken or a miss-
ing ground may aggravate this problem. Normally these noises will be below the
background or “band” noise. Increase the separation between the power supply and
the receiving antenna. Use an outdoor antenna. This will reduce the amount of signal
picked up from the power supply and also increase the amount of the desired signal.
5. The conducted RF noise from these power supplies is limited to the maximum allow-
able levels by internal ltration. The ltered RF noise currents are by-passed to the
chassis of the power supply. The chassis is, in turn connected to the earth ground pin
of the AC input power cord (for Class 1 units). Thus, the ltered noise currents are
intentionally leaked to the earth ground. This is termed as the “earth leakage cur-
rent”. For safety against electric shock, this earth leakage current is also required to
be limited. It will be seen that these two requirements are conicting.
NOTE:
- In some cases, to prevent electric shock hazard due to abnormal leakage current
(like in marinas, spas, hot tubs, wet spaces etc.), The AC outlet circuits / receptacles
in these areas are served through a GFCI ( ground fault circuit interrupter ). This
GFCI is normally set to trip when it senses an earth leakage current > 5 mA. A single
GFCI may be serving multiple AC outlet circuits / receptacles and therefore, will be
sensing the sum of all the leakage currents of the devices connected to these. As
the switching power supplies have intentional leakage current.
SECTION 13 | Limiting Electromagnetic
Interference (EMI)

18 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 19
- As explained above, it may trip a GFCI feeding multiple AC outlet circuits / recepta-
cles. In such cases, disconnect devices connected to the other AC.
- Outlet circuits / receptacles served by this GFCI.
6. Following additional guidelines may be followed to reduce the effects of RF Noise:
A. Use additional appropriate AC radio frequency interference (RFI) power line
lter immediately before the AC input of the power supply. For example,
125VAC, 30A lter “F1700DD30” from curtis industries (www.curtisind.com)
or similar. Filtered, ferrite coated cord set (www.emceupen.com ) is another
choice. These cord sets, with integral line interference lters, reduce common
and differential mode interferences over a wide frequency range. Because
they are shielded, they are also effective against radiated interferences. In
addition to the built-in lter networks, the cable conductors are coated with
an RF absorbing ferrite compound. This provides additional attenuation at
high frequencies that is lacking in most regular LC lters. The RF absorption of
the ferrite-coated cable avoids resonance’s at high frequencies, reducing the
conducted and radiated RF noises even further.
B. Use additional appropriate DC radio frequency interference (RFI) power
line lter immediately after the DC output of the power supply. For example,
80VDC, 100A lter from “DC” series by corcom (www.corcom.com) or 80VDC,
100A lter from “FD” series by curtis industries (www.curtisind.com) or
similar.
C. Twist the Positive and Negative wires from the output of the power supply to
the radio.
D. The DC side Positive and Negative outputs of these power supplies are iso-
lated from the chassis. As explained at paragraph 5 above, the noise currents
are ltered to the chassis ground and the chassis ground is connected to the
earth ground through the earth ground pin of the AC power outlet recepta-
cle. Avoid connecting (referencing) the DC Negative output terminal of the
power supply to the earth ground.
E. Connect a 1/4” wave length of wire on the Negative terminal of the power
supply. Connect one end of the wire to the Negative terminal and leave the
other end free. The wave length corresponds to the wave length of the inter-
fering frequency. (May not be practical for long wave lengths).
[ Formula: Wave Length (Meters) = 300 / Frequency In Mhz ]
SECTION 13 | Limiting Electromagnetic
Interference (EMI)

20 | SAMLEX AMERICA INC.
SECTION 14 | Specications
SPECIFICATIONS SEC-2450BRM SEC-2440BRM SEC-2430BRM
No. Of Modules 5 4 3
Input Voltage Range 105 to 125V AC, 50/60 Hz
Input Current 20A 16A 12A
Output Voltage (At Terminals L+ & L- , See Page 12)
- Nominal, VDC 27.6V
- No Load, VDC 27.8V
- Full Load, VDC 27.4V 27.45V 27.40V
Output Regulation* 1%
Output Current
- Continuous 50A 40A 30A
- Surge 57.5A 46A 34.5A
Output Current Limit 60A 48A 36A
Output Ripple, Peak To Peak 150mV
Output Noise, Peak To Peak Less than 1.5V
Cooling Forced Air, 2 Fans
Operating Temperature 0˚C to 40˚C / 32˚F to 104˚F
Protections
- Short Circuit YES
- Current Limit YES
- Fan Failure LED and Buzzer
- Input Surge Supression YES
Fuse / Breaker Module Fuse – 250V, 4A. Unit has a Breaker.
Dimensions (mm / inches)
(19” Rack Mount, 2U Height) 482.6 x 403.86 x 91.44 / 19 x 15.9 x 3.6
Power Cord Conductors 12AWG / 3 Conductor
Power Cord Plug
- SEC-2450BRM 125V, 30A, NEMA L5-30P, Twist Type
Power Cord Plug
- SEC-2440BRM / SEC-2430BRM 125V, 20A, NEMA 5-20P
Weight, Kg. / Lbs 25 / 55.12 23.5 / 51.7 22 / 48.4
* At Module Output S5, S6 – Fig. 1
Note: Specications Subject To Change Without Notice