INSTALLATION MANUAL
PSE series AC inputs
2011-04-26 Copyright 2000-2011 Page 6(13)
•If you intend to use alarm feature,
please consult section 7 Under
voltage Alarm on page 10.
5. Connect the input cables. Bundle input
cables together separated from the output
cables.
6. Switch on the input voltage.
Beware of hazardous voltages!
The output voltage can be adjusted between
±10% of nominal output voltage with the
potentiometer marked V.ADJ on the front
panel. Clockwise turn increases the output
voltage. The potentiometer has 15 turns. If
you have connected units in parallel on the
output, the procedure of adjusting the output
voltage is described in “Adjusting output
voltage when units are paralleled on the
output” on page 7.
3 Parallel connection
If a redundant power supply system is
requested, two or more converters can be
connected in parallel. To achieve redundancy
the number of converters must be
dimensioned to carry the whole load even if
one converter is faulty. The option C or CR
series diode on the output must be provided.
Connect your load to the + output after the
series diode (cathode).
Another reason for connecting two or more
converters in parallel is to get more power.
The option C must be provided and use the
output with series diode. When the series
diode C or CR option is used the Sense option
S, see section 5 page 9, cannot be used.
3.1 Series diode on the output,
option C
A series diode is necessary if the output is
connected in parallel with another power
supply or if you require redundant operation.
If a converter breaks down with an internal
short-circuit on the output and other
converters are connected in parallel on the
output, the broken unit will short-circuit the
others if the series diode is not used. This
might cause excessive heat or even fire in the
faulty unit.
The series diode protects the converter output
from external voltage sources.
If the series diode is used, we recommend to
use the alarm function option B alarm circuit.
The alarm relay will switch to ”ALARM” on
the faulty unit if one power supply breaks
down in a redundant power supply system.
Otherwise there will be no alarm indication
from a faulty power supply unless all units are
in current limit.
3.2 Series diode with series
resistor, option CR
This option is an extension of 3.1 Series
diode. When several PSE units are connected
in parallel with so called “hot plug in” in 19”
sub-rack, a built in series resistor and series
diode is provided that will automatically
balance the current between units.
The series resistor will provide the Ud
function described in section 3.4 and Figure
4. Thus no special cable arrangments are
needed with this CR option.
3.3 Output under voltage alarm
If one DC/DC converter fails in a redundant
power system an alarm signal should be
detected.
The PSC has a logic open collector alarm to
provide a logic signal. An optional relay dry
contact output, see section 8 page 10.
The figure 2, next page shows a N+1 system
with two units for the load and one for the
redundancy. Each Power supply has a built in;
series diode (C), balancing resistor (R) and
alarm Relay option B. The alarm is cascade
connected.
With the CR option a hot plug-in can be
achieved if the output voltage is correctly
adjusted. Use instruction section 3.6 -3 below.
