Specifications

CONTROLS AND MONITORING:
OUTPUT VOLTAGE CONTROL: Potentiometer VR1
is a multi-turn potentiometer for fine adjustment
of the output voltage. It is preset at 28V. It can
adjust the output voltage from 26.8 to 28.5V
LED FOR MONITORING STATUS OF OPERATON:
LED 1/ LED2 provide connection for LED for
monitoring the status of operation. In the Samlex
N+1 DC Power System series SEC-24XXBRM,
one green L.E.D. is taken to the front panel indi-
cation ”PSM Status”. The second LED connector
is for remote monitoring.
PROTECTIONS:
SHORT CIRCUIT PROTECTION: In the event of a short
circuit, the PWM controller will be shut down and the
output will dip to near 0V. The green LED(s) connected
to LED1/LED2 will flash. The unit will reset automatically
once the short circuit condition is removed
.
CURRENT LIMITING
: The module will enter this mode
when the load tries to draw more than the limiting value
of 11.5A. Under this condition, there will be loss of
voltage regulation and the output voltage will drop. The
green LED(s) connected to LED1/LED2 will, however,
remain illuminated, but dimmed. The unit will reset
automatically as soon as the overload condition is
removed.
INPUT SURGE PROTECTION: The module is pro-
tected against input voltage surges
. ( By tripping the
external AC side breaker ).
5.
NO OUTPUT VOLTAGE, GREEN LED(s) CONNECTED
TO LED1/LED2 ARE FLASHING
• There is a short circuit on the output side
• Switch off the unit. Disconnect the load from the
output terminals. Switch on the unit. If the unit now
operates normally, there is a short circuit in the
external load circuit and should be removed .
• If short circuit condition persists even after removal
of external load, switch off the unit and contact tech-
nical support.
WHEN TWO OR MORE UNITS ARE OPERATING IN PARALLEL
• The output voltage of the individual modules is not
the same or the forced share control circuitry of the
module(s) is defective. Adjust the voltages of the
module(s) to the same voltage. If the problem per-
sists, call tech support.
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 switch-
ing devices due to their fast switching current transi-
tions: harmonics of the switching frequency and
broadband noise created by under-damped oscilla-
tions in the switching circuit. 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 ( ex-
cepting 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.