Reference Manual Manual
All parameters are specified at 12V, 4.5A, 230Vac input, 25°C ambient and after a 5 minutes run-in time unless noted otherwise.
Rockwell Automation Publication 1606-RM016A-EN-P — February 2014 21
Bulletin 1606 Switched Mode Power Supplies
20.11. Use at Low Temperatures (-25°C to -40°C)
Please pay attention to the following factors when operating the unit at low te mperatures. Perform tests to verify
suitability in your application.
- The ripple & noise voltage will increase. For the rst minutes after turning on the unit at -40°C, the ripple and
noise voltage can be up to typically 400mVpp depending on load and input voltage. Once the unit heats up,
the ripple & noise voltage will decrease typically to 90mVpp.
- The start-up delay can be up to 5 seconds. It is a continuous turn-on process without any voltage dips or start-
up attempts.
20.12. 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 denes 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 Type IP66 Box PK 9510 100, plastic, 130x130x75mm
Input: 230Vac
Case A:
Load: 12V, 4.5A; load is placed outside the box.
Temperature inside the box: 42.3°C (in the middle of the right side of the power supply with a distance of 1cm)
Temperature outside the box: 21.7°C
Temperature rise: 20.6K
Case B:
Load: 12V, 3.6A; (=80%) load is placed outside the box.
Temperature inside the box: 40.6°C (in the middle of the right side of the power supply with a distance of 1cm)
Temperature outside the box: 21.9°C
Temperature rise: 18.7K