20
21
-1
1
40
Power Supply PS1000-A6-12.16
Application Notes
27.5
Parallel Use to Increase Output Power
Power supplies can be paralleled to increase the output power. The output voltage of all power
supplies shall be adjusted to the same value (±100mV) with the same load conditions
on all units, or the units can be left with the factory settings. There is no feature included
which balances the load current between the power supplies. Usually the power supply
with the higher adjusted output voltage draws current until it goes into current limitation.
This means no harm to this power supply as long as the ambient temperature stays
below 40°C.
If more than three units are connected in parallel, a fuse or circuit breaker with a rating
of 25A or 32A is required on each output. Alternatively, a diode or redundancy module
can also be utilized.
Energize all units at the same time to avoid the overload
Hiccup
mode. It also might
be necessary to cycle the input power (turn-off for at least five seconds), if the output was
in
Hiccup
mode due to overload or short circuits and the required output current is higher than
the current of one unit.
Restrictions
•
Keep an installation clearance of 15mm (left/right) between two power supplies and avoid
installing the power supplies on top of each other.
•
Do not use power supplies in parallel in mounting orientations other than the standard
mounting orientation (terminals on bottom of the unit) or in any other condition where
a derating of the output current is required (e.g. altitude, …).
Pay attention that leakage current, EMI, inrush current, harmonics will increase when using
multiple power supplies.
Figure 27.5 Parallel use to increase output power
Unit A
AC
DC
Unit B
AC
DC
-
+
-
+
Load
+
-
