Samlexpower SEC-2430BRM Installation instructions

MODELS : SEC-2430BRM
SEC-2440BRM
SEC-2450BRM
Please read this manual before operating your power supply.
INSTALLATION & OPERATING MANUAL
EXPANDABLE 24 VDC POWER SUPPLY
N+1 DC Power System
with Battery Backup / Charging Function

• PROVIDES N + 1 REDUNDANCY
• ALLOWS CONNECTION OF EXTERNAL BATTERIES FOR BACKUP
• EXPAND OUTPUT POWER BY ADDING POWER MODULES
• UP TO 50 AMPS CONTINUOUS POWER
• VOLT / AMPERE METER
• OPERATION STATUS L.E.D.
• FAN FAILURE ALARM AND WARNING L.E.D.
• REMOTE MONITORING AND INDICATION
• 19” RACK MOUNT
• 2 YEAR WARRANTY / TOLL FREE TECHNICAL SUPPORT

TABLE OF CONTENTS
Topic Page
Important safety instructions 1,2
Description and application 3
Design and principle of operation 3
Cooling and warning for fan failure 3
Front panel controls and indicators 4
Rear panel controls 4,5
Protections 5
Installation and operation 6
Operation of battery back-up 7
Output voltage adjustment 8,9
Installation and removal of modules 9,10
Trouble shooting 11,12
Limiting electromagnetic interference 13,14,15
Specifications 16
Appendix : Figures 1 to 3 17,18
Warranty information 19
Notes 20

IMPORTANT SAFETY INSTRUCTIONS
Please read before using your power supply.
CAUTION !
ALL ELECTRICAL INSTALLATIONS MUST MEET LOCAL AND NA-
TIONAL WIRING CODES AND SHOULD BE PERFORMED BY A QUALI-
FIED ELECTRICIAN
.
OPERATION OF COOLING FAN
THE HEAT PRODUCED IS EXTRACTED BY FORCED AIR COOLING. IN CASE
ANY OF THE FANS FAILS, 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 V AC/ 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 PLUG OF THE POWER CORD. SEC-2440BRM MUST BE POWERED
FROM A 20A CIRCUIT AND MUST BE PLUGGED INTO A 20A AC OUTLET
WHICH WILL ACCEPT THE 20A MOULDED PLUG PROVIDED WITH THE POWER
CORD. SEC-2430BRM MAY BE POWERED FROM A 15A CIRCUIT. A 15A PLUG
HAS BEEN PROVIDED SEPARATELY WHICH CAN BE USED TO REPLACE THE
20A PLUG FOR THE SEC-2430BRM.
CAUTION ! REPLACEMENT SHOULD BE DONE BY A QUALIFIED ELEC-
TRICIAN. PLEASE ENSURE PROPER POLARITY OF THE CONNECTIONS AS
FOLLOWS :
“ L ” LINE BLACK WIRE
“ N ” NEUTRAL WHITE WIRE
EARTH GROUND GREEN WIRE
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 NUM-
BER, 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 FIRE HAZARD )
2. THE EXTENSION CORD WIRE SIZE SHOULD BE MINIMUM 12 AWG, 20 A.
1.

LOAD AND BATTERY CONNECTIONS
THE LOAD & BATTERY TERMINALS ON THE POWER SUPPLY HAVE A TUBU-
LAR 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 OVERHEATED 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 CONNEC-
TOR FOR MAKING A FIRM CONNCECTON. 4 PIECES OF PIN TYPE CONNEC-
TORS 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
o
C). 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. DIS-
TANCE FROM THE POWER SUPPLY. THICKER WIRING WILL BE REQUIRED
FOR LONGER DISTANCES. THINNER WIRES WILL CAUSE OVERHEATING
AND EXCESSIVE VOLTAGE DROP :
FOR SEC-2450BRM - 50 A # 4 AWG | UP TO
FOR SEC-2440BRM - 40 A # 6 AWG | 6’
FOR SEC-2430BRM - 30 A # 8 AWG | DISTANCE
ENSURE THAT THE AC POWER IS SWITCHED OFF WHEN ANY DEVICE IS BE-
ING CONNECTED TO THE POWER SUPPLY.
DO NOT ALLOW THE ENDS OF THE POSITIVE AND NEGATIVE WIRES TO
TOUCH EACH OTHER.
FUSE REPLACEMENT
ENSURE PROPERLY RATED FUSE ( 250 V, 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
QUALIFIED TECHNICIAN. INCORRECT REASSEMBLY OR REPAIR MAY RE-
SULT IN A RISK OF ELECTRIC SHOCK OR FIRE WHICH MAY
RESULT IN PERSONAL INJURY AND PROPERTY DAMAGE
.
2.

DESCRIPTION
This is a 19 inch Rack Mount Power Supply which converts 120 V , 60 Hz. AC power
into regulated 28 V DC , +/- 1% (At module output*) delivering up to a maximum of
50 A continuous ( up to 57.5 A 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 (Please see page 7 for explanation.)
APPLICATIONS
The unit is designed for the following applications:
1. N+1 redundant systems
2. Future power level expansion
3. Uninterrupted DC output when used in conjunction with an external battery backup.
DESIGN AND PRINCIPLE OF OPERATION
The unit is designed using advanced switch mode technology and load share cir-
cuitry for high reliability, high efficiency 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 MODULES” ) that are connected for parallel operation with true
current sharing . Each module is a stand alone power supply which delivers up to a
maximum of 10 A continuous ( 11.5A surge) . By equalizing the output currents,
uniform thermal stress of the individual modules is also ensured which has utmost
importance for long term reliability of electronic components. The operating principle
of the load share mechanism is to measure the output current of each individual
module and to be able to modify the output voltage of the units until all the participat-
ing modules deliver equal output currents. Each module is required to be inter-
connected with each other to a common “SHARE BUS” through a pair of parallel
pins marked “JUMP1” and jumper wires (Fig. 1 & 2). Typically, the output currents
for the paralleled units will be within 10% of each other at full output current. The
output is delivered through schottky isolating diodes to enable connection of external
battery for uninterrupted back-up power.
• SEC-2450BRM has 5 modules of 10A each = 50 Amps
• SEC-2440BRM has 4 modules of 10A each = 40 Amps
• SEC-2430BRM has 3 modules of 10A each = 30 Amps
COOLING AND 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 HOLES ARE NOT BLOCKED.
3.

A warning circuit monitors the operational condition of the fans. In case of a fan fail-
ure, a buzzer will sound and the red LED indicating “TEMP. FAULT” will light up.
The unit should be switched off immediately and the defective fan should be re-
placed. NEVER LOAD THE UNIT WHEN THERE IS AN AUDIBLE ALARM AND
THE TEMP. FAULT LED IS ILLUMINATED.
FRONT PANEL CONTROLS AND INDICATORS
The following controls and indicators are provided on the front panel :
1. POWER ON/OFF SWITCH / BREAKER. The rocker switch will illuminate when
switched on. A 20A circuit breaker is built in to provide 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. METER CHANGE-OVER SWITCH. Switches the combined meter between am-
meter and voltmeter
4. L.E.D “ PSM STATUS (1 to5)”. During normal operation, the green LED of each
Power Supply Module (PSM) will light. In case a power supply module (PSM) fails, its
corresponding LED will go off. LED 1 is for the left most module (near the on/off
switch)
5. L.E.D “ TEMP. FAULT ” : In case of fan failure, this red LED lights up and a
buzzer is sounded.
REAR PANEL CONNECTORS
The following output connectors have been provided.
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.
1.
5. 2.
4. 3.
4.

3. REMOTE MONITORING AND INDICATIONS . A 25 pin D-sub connector has
been provided for remote monitoring and indication. Pin connections are given
below. Pins 2 and 16 are meant to indicate availability of input AC power. Cur-
rent indication on pins 18 & 6 is 0.5mV per Amp. (Shunt ratio 25mV / 50A)
ITEM NUMBER ID FUNCTION
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 0 V. The green LEDs will flash.
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 specifications. Under this
condition, there will be loss of voltage regulation and the output voltage will drop. The
“PSM STATUS” LED will, however, remain illuminated, but dimmed. The unit will
reset automatically as soon as the overload condition is removed .
INPUT SURGE PROTECTION : The unit is protected against input voltage surges.
1 Pin 2 Black AC 5V 0.25A
Pin 16 White AC 5V 0.25A
2 Pin 12 Orange Temp Fault Led +
Pin 19 Green Temp Fault Led -
3 Pin 7 Gray PCB 1 Power LED+
Pin 20 Violet PCB 1 Power LED-
4 Pin 8 Violet PCB 2 Power LED+
Pin 21 Blue PCB 2 Power LED-
5 Pin 9 Blue PCB 3 Power LED+
Pin 22 Green PCB 3 Power LED-
6 Pin 10 Green PCB 4 Power LED+
Pin 23 Yellow PCB 4 Power LED-
7 Pin 11 Yellow PCB 5 Power LED+
Pin 24 Orange PCB 5 Power LED-
8 Pin 25 Red DC Volt Output +
Pin 13 Black DC Volt Output -
9 Pin 18 Gray DC Current +
Pin 6 Blue DC Current -
5.

FAN FAILURE WARNING INDICATOR AND ALARM : If forced air cooling is
stopped due to failure of any one or both the fans, the red “ TEMP. FAULT “ LED will
be illuminated and an alarm buzzer will be activated. The unit is required to be
switched off immediately as loss of forced air cooling may result in major damage to
the unit.
INSTALLATION AND 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 side of the fans at the
sides or on the discharge side vent holes 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 firm 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 120 V, 60 Hz standard AC outlet . The outlet should be
rated at 30A for SEC2450BRM, 20A for SEC-2440BRM and 20/15A for SEC-
2430BRM.
7. Switch on the unit by pressing the power on/off switch to on position. The switch
will be illuminated confirming that input power is available.
8. A short beep may be generated by the temperature fault alarm circuit on power-
ing on the unit . This is normal. Please disregard.
9. Switch the volt/amp change-over switch to the “VOLT” position. The voltmeter
should read 27.8 V on no load (Please see explanation on Page 7)
10. Switch on the D.C. loads. The output voltage should be 27.6 V nominal (Please
see explanation on Page 7)
11. 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 mod-
ules installed.
6.

Regulated output voltage of 28 V +/ - 1% from the modules ( measured at screw ter-
minals 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 Di-
ode 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 28 V +/- 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. The voltage at the output terminals
LOAD + and LOAD – will be as follows :
At no load Approx. 27.8 V
At 10 A load Approx. 27.6 V
At loads > 10 A Approx. 27.6 V minus 5 mV per Amp above 10A
THE BATTERY SHOULD BE LOCATED IN A WELL VEN-
TILATED AREA TO SAFELY DISSIPATE HYDROGEN GAS
PRODUCED DURING THE CHARGING PROCESS.
OPERATION OF BATTERY BACK-UP
WARNING!
7.
Please refer to the schematic at fig. A above.
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 resis-
tors R1 & R2. (These resistors will limit the maximum charging current to about 8
Amperes.)

8.
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.
When the input A.C. power returns, the battery will be isolated and the load current
will once again be supplied by the power supply. The discharged battery will re-
charge through R1 & R2.
NOTE: The value of charge limiting resistors is based on a typical 100AH deep
cycle marine battery. If a different type of battery is used, the value of the resistor
should be adjusted to meet associated charging requirements.
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 28 V. A precision multi turn potenti-
ometer VR1 is provided for fine adjustment of the output voltage of the module (The
adjustment range is 26.8 V to 28.5 V ).
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 28 V, it’s current share control circuitry will not func-
tion properly and it’s LED will start flashing. The LEDs of the other modules which are
putting out 28 V will remain continuously lighted and the output voltage of the com-
mon DC bus (before the Schottky Diode D1) will be 28 V.
If the output voltage of any module is higher than 28 V, it’s LED will remain continu-
ously lighted but the LEDs of all the other modules will flash 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 fine, multiple turns will be required even for small voltage change.
Turn clockwise for decreasing and anti clockwise for increasing . The adjustment range
is 26.8 V to 28.5 V
As explained under OPERATION OF BATTERY BACK UP on page 7, although the
output voltage at the module terminals S5 and S6 ( Fig.1) or at the common DC bus
(before the Schottky Diode D1) is tightly regulated at the preset value of 28 V +/-
1%, the voltage at the output terminals Load + and Load - will vary between 27.8 V
at no load to 27.45 V at full load of 50 A due to the forward voltage drop of the isolat-
ing Schottky Diode D1 and the drop along the DC bus and wiring.

INSTALLATION AND REMOVAL OF POWER SUPPLY MODULES
NOTE: INSTALLATION AND REMOVAL OF POWER SUPPLY MODULES
SHOULD BE PERFORMED ONLY BY QUALIFIED PERSONNEL
CAUTION !
Before removing a defective module or installing a new one, switch off the 120 V , 60
Hz input power and unplug the power cord from the mains outlet.
NOTE :
Please refer to the layout diagram of the module at Figure. 1 located on page 17.
9.
The output voltage of the paralleled modules or the common DC bus (before the
Schottky Diodes D1) can be adjusted between 26.8 V and 28.5 V 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 load Module voltage minus 0.2V
At 10 A load Module voltage minus 0.4V
At loads > 10 A Module voltage minus 0.4V minus 5 mV per Amp above 10A
Procedure
• Switch off the unit and unplug the power cord.
• The output voltage of each individual module is adjusted one by one starting
from the left most module – Module 1 and progressing to the right most module
– Module No. 5 ( for SEC-2450BRM ). AC input is connected only to the mod-
ule being adjusted. AC input to the remaining modules is disconnected
• Remove the AC input connections ( female quick connect terminals connected to
the L and N male tab terminals on the modules – Fig. 1 ) from Module Nos. 2, 3,
4 and 5. Temporarily insulate these female quick connect terminals with insulat-
ing tape for safety. Now, only Module No. 1 can be energized.
• Switch on the power supply. Only Module No. 1 will operate. Adjust the output
voltage of this module to the desired value with the help of potentiometer VR1
(Fig.1) Measure the voltage at the screw terminals S5 and S6 (Fig.1)
• Switch off the power supply. Remove the AC input connection from Module No.
1. Temporarily insulate these terminals with insulation tape. Remove temporary
insulation from the AC connectors for Module 2 and connect them to Module 2.
Now only Module 2 can energize.
• Switch on the power supply. Only Module No. 2 will operate. Adjust the output
voltage of this module to the desired value with the help of potentiometer VR1
(Fig.1). Measure 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 individu-
ally 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 five modules.
• Power on the unit and check that all the 5 “PSM Status” LEDs are lighted. This
will confirm that the voltage adjustment has been completed successfully

10.
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 and SEC-2440BRM by steps of 10A to a
maximum of 50A. For example, an SEC-2430BRM (30 A, with 3 modules) can be up-
graded to SEC-2440BRM (40A) by adding 1 more module or to SEC-2450BRM by add-
ing 2 more modules .
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 relative to 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 fix 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). Connect the black wire to the
male tab terminal marked L(Fig.1) and white wire to the male tab terminal marked N(Fig.1)
5. Green LED indication for proper operation of the module is provided from 2 pin male quick
connect terminals marked LED1 and LED2 (Fig.1). One LED terminal is used for the front
panel LED under “PSM Status (1 to 5)” and the other for remote indication through the D-Sub
connector. Connection 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 PCB 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 LED1 / LED2 (Fig.1). If remote LED indication is also required, then
connect the female quick connect terminal of the corresponding colour coded wire for the
remote LED connection to the male quick connect terminal marked LED1/ LED2 (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 connect terminal
marked JUMP1 (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 con-
nect it to the male quick connect terminal marked JUMP1 (Fig.1)
7. Use cable ties to secure all loose wiring
8. Replace the top cover. Power on the unit and confirm that the “PSM Status” LEDs of the
newly installed modules are lighted.

REMOVING A DEFECTIVE MODULE
1. Remove the top cover plate by unscrewing the 10 screws.
2. Locate 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 the LED wire connection from terminals “LED 1 & LED 2” .
5. Remove the “SHARE BUS” wire female socket connector from the terminal
“JUMP1”. 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 “JUMP1”
TERMINALS ARE INTERCONNECTED.
6. The module can now be removed .
TROUBLE SHOOTING
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
POWER SWITCH TRIPS
· The breaker , which is a part of the power on/off switch, has tripped due to
abnormal condition . Call technical support
“TEMP. FAULT” 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 PRO-
HIBITED TO USE THE UNIT WITHOUT FORCED COOLING. Call techni-
cal support.
· If both the fans are running, the small fan status monitoring PCB may be
defective. Call technical support.
11.

“ PSM STATUS ” LED(S) DOES NOT LIGHT UP
· The associated module has become defective. The unit will still operate
normally as the remaining 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
· 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.
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 27.6 V, then switch off all the loads. If the voltage in this
condition is also low, switch off the unit and contact technical 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 28 V as explained on page 8.
If the problem still exists, contact technical support.
12.

LIMITING ELECTROMAGNETIC INTERFERENCE (EMI)
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 cir-
cuit. The secondary source is from the bridge rectifier, both rectifier noise
and diode recovery. The AC input rectifier / capacitor in the front end of the
switching power supplies ( excepting 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 nor-
mal operation of the power supply can be disturbed due to RF noise getting
coupled into the power supply. Thus, the power supply may generate exces-
sive RF noise and lose output voltage regulation due to excessive transmitter
energy being coupled through the AC / DC lines to the power supply’s regu-
lator 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 missing 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 an-
tenna. This will reduce the amount of signal picked up from the power supply
and also increase the amount of the desired signal.
13.

5. The conducted RF noise from these power supplies is limited to the maximum
allowable levels by internal filtration. The filtered 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
filtered noise currents are intentionally leaked to the earth ground. This is
termed as the “Earth Leakage Current”. For safety against electric shock, this
earth leakage current is also required to be limited. It will be seen that these
two requirements are conflicting.
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
as explained above, it may trip a GFCI feeding multiple AC outlet circuits /
receptacles. 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
filter immediately before the ac input of the power supply. Recommended:
Corcom Inc. ( www.cor.com ) “Q” series. Filtered, ferrite coated cord set
(www.emceupen.com ) is another choice. These cord sets, with integral line
interference filters, 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 filter 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 filters. 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
filter immediately after the dc output of the power supply. Recommended:
Corcom Inc.(www.cor.com ) “DA” / “DC” series
14.

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 filtered to the chassis ground and the chassis ground is connected to the
earth ground through the earth ground pin of the AC power outlet receptacle.
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 sup-
ply. 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 interfering
frequency. (May not be practical for long wave lengths)
[ Formula: Wave length (Meters) = 300 / frequency in MHz
15.

SPECIFICATIONS
NO. OF MODULES 3 4 5
INPUT VOLTAGE RANGE 105 TO 125 V AC, 60 HZ
INPUT CURRENT 12A 16A 20A
OUTPUT VOLTAGE (At terminals L+ & L- , See page 7)
NOMINAL, VDC 27.6V
NO LOAD, VDC 27.8V
FULL LOAD, VDC 27.5V 27.45V 27.4V
OUTPUT REGULATION 1%
(At module output S5, S6—Fig. 1)
OUTPUT CURRENT
CONTINUOUS 30A 40A 50A
SURGE 34.5A 46A 57.5A
OUTPUT CURRENT LIMIT 36A 48A 60A
OUTPUT RIPPLE, PEAK TO PEAK 150mV
OUTPUT NOISE, PEAK TO PEAK LESS THAN 1.5V
COOLING FORCED AIR, 2 FANS
OPERATING TEMPERATURE 0 TO 40 C
PROTECTIONS
SHORT CIRCUIT YES
CURRENT LIMIT YES
FAN FAILURE LED AND BUZZER
INPUT SURGE SUPRESSION YES
FUSE MODULE FUSE – 250 V, 4 A
UNIT HAS SWITCH / BREAKER
250 V, 20 A
DIMENSIONS 19” X 15.9” X 3.6”
WEIGHT, LBS 22 23.5 25
NOTE: SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
16.
SEC-2430BRM SEC-2440BRM SEC-2450BRM

Figure 1 - Layout of Power Supply Module
S1 to S4 Holes for 4 screws to fasten the module to the chassis
S5 & S6 Holes for 2 screw to connect to the Positive and Negative output BUS Bars.
L & N L ( line ) and N ( neutral ) terminals for 120V, 60 Hz input power supply wires LED 1, 2 Terminal for “LED “ PSM status JUMP 1 Jumper terminal for connecting share BUS wire F1 Fuse VR1 Potentiometer for output voltage adjustment
17.
Figure 1.