PU1000/PU600 INSTALLATION MANUAL
10229-15.doc
Polyamp AB, Sweden
www.polyamp.com
Page
5 (10)
4. Connect the input cables. Bundle input cables
together at the terminals separated from the output
cables. Make the same arrangement on the output
side. This is to make sure one cable will not bridge
the insulation barrier in case of coming lose.
5. Start the converter with your external input
disconnection device.
Beware of hazardous voltages!
•
The output voltage can be ad10% to
-5% 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 are using current sharing, the procedure
of adjusting the output voltage is described
in
3.3
Voltage adjustment with current
sharing
on page 6.
5.
Replace plastic cover.
6.
When the converter is disconnected, switch-off
the input voltage with the disconnecting unit.
Disconnect the input cables first, then output
and last the protective case connection.
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. Connect your
load to the + output after the series diode, see
Figure 1
.
Another reason for connecting two or more
converters in parallel is to get more power. Use the
output with series diode, see
Figure 1
.
You should
not use external sense
when the unit
are in parallel on the output.
3.1 Series diode on the output
The series diode protects the converter output from
external voltage sources. 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.
If the series diode is used, the alarm relay will
switch to ”ALARM” on the faulty unit if one
converter breaks down in a redundant power supply
system. Otherwise there will be no alarm indication
from a faulty converter unless all units are in
current limit and the output voltage drops 10%
below nominal output voltage.
When the series diode is used the total output
power of the converter must be
derated.
See data
sheet.
•
On 24Vd.c. output by 10%.
•
On 48Vd.c. output by 5%.
Do not forget to fuse the inputs separately to
achieve redundancy.
3.2 Current sharing
All models include the automatic current sharing
feature, which we recommend to use in parallel
configuration. A maximum of 10 (10) units can be
connected in parallel.
If more than 10 units should be connected in
parallel, contact Polyamp.
Connect a cable (0.25-1.0mm
2
) with a maximum
length of 3.0m between the ”CURRENT SHARE”
connectors of all units.
The converter with the highest output voltage will
then automatically become ”current master”. This
converter will then run with a few percent higher
output current than the others. If the master
converter for some reason breaks down, another
converter automatically becomes ”current master”.
To achieve good power sharing, the voltage drop
between the minus poles must be kept as low as
possible, see
Figure 1
. The plus poles can either be
connected as in
Figure 1
or have separate cables to
the load.
At light load (if the total load is less than 5% of the
total rated power) the yellow ”C. MASTER” LED
might flicker between the units. As the load
changes different units ”C. MASTER” LED might
be lit. All this is normal.