Specifications

DESCRIPTION:
This is a component power supply module for Samlex N+1
DC power system series SEC-24xxBRM (SEC-2430BRM,
SEC-2440BRM, SEC-2450BRM) It converts 120V , 60 Hz
AC into tightly regulated 28 VDC at 10A continuous. Two or
more of these modules can be operated in parallel with ac-
tive current sharing.
APPLICATIONS:
This unit is designed for the following applications:
A) As a component power supply module (PSM) in Sam-
lex N+1 DC Power System Series SEC-24xxBRM.
B) Independent open frame power supply with active
current sharing for parallel operation.
DESIGN AND PRINCIPLE OF OPERATION:
The power supply module is designed using advanced switch
mode technology and load share circuitry for high reliability,
high efficiency and minimum size and weight. Two or more
power supply modules (referred to as PSM “POWER SUP-
PLY MODULES”) can be connected for parallel operation
with true current sharing. Each module is a stand alone
power supply which delivers up to a maximum of 10A con-
tinuous (11.5A surge). By equalizing the output currents,
(when 2 or more modules are operating in parallel), uniform
thermal stress of the individual modules is 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 individ-
ual module and to be able to modify the output voltage until
all the participating modules deliver equal output currents.
When connected in parallel, 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. Typically, the output currents for the paralleled units
will be within 10% of each other at full output current.
COOLING:
Heat generated in the module is dissipated through the heat
sink mounted on the PCB.
When the module is being used as open frame power supply
either singly or in parallel, forced air cooling is required to be
provided to cool the heat sink.
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. Recom-
mended: 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
12.