All parameters are specified at 24V, 2.5A, 230Vac input, 25ªC ambient and after a 5 minutes run-in time unless noted otherwise.
26
Rockwell Automation Publication 1606-RM032A-EN-P — April 2014
Bulletin 1606 Switched Mode Power Supplies
25.9. Series Operation
Power supplies of the same type can be connected in series for higher
output voltages. It is possible to connect as many units in series as needed,
providing the sum of the output voltage does not exceed 150Vdc. Voltages
with a potential above 60Vdc are no longer SELV and can be dangerous.
Such voltages must be installed with a protection against touching.
Earthing of the output is required when the sum of the output voltage is
above 60Vdc.
Avoid return voltage (e.g. from a decelerating motor or battery) which is
applied to the output terminals.
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 series in mounting
orientations other than the standard mounting orientation (terminals on the bottom of the unit).
Unit B
-
+
Load
+
-
AC
DC
AC
DC
-
+
Unit A
Earth
(see notes)
Please note that leakage current, EMI, inrush current and harmonics all increase when using multiple power supplies.
25.10. Inductive and Capacitive Loads
The unit is designed to supply any kind of loads, including capacitive and inductive loads.
25.11. Back-feeding Loads
Loads such as decelerating motors and inductors can feed voltage back to the power supply. This feature is also called
return voltage immunity or resistance against Back- E.M.F. (Electro Magnetic Force).
This power supply is resistant and does not show malfunctioning when a load feeds back voltage to the power supply.
It does not matter whether the power supply is on or off.
The maximum allowed feed-back-voltage is 63Vdc. The absorbing energy can be calculated according to the built-in
large sized output capacitor which is specified in section 6.
25.12. Use in a Tightly Sealed Enclosure
When the power supply is installed in a tightly sealed enclosure, the temperature inside the enclosure will be higher
than outside. In such situations, the inside temperature defines the ambient temperature for the power supply.
The following measurement results can be used as a reference to estimate the temperature rise inside the enclosure.
The power supply is placed in the middle of the box; no other heat producing item is inside the box.
Enclosure:
Rittal Typ IP66 Box PK 9522 100, plastic, 254x180x165mm
Load:
48V, 16A; (=80%) load is placed outside the box
Input:
230Vac
Temperature inside enclosure:
51.0°C (in the middle of the right side of the power supply with a distance of 2cm)
Temperature outside enclosure: 21.8°C
Temperature rise:
29.2K