Micro Technic Micronix PV-5127 - Manual (Page 30)

Users Manual & Installation Guide
PV- 5127: Power supply module with UPS
Page 30 of 31
Thermal considerations
When installing the Micronix PV-5127 in a PC/104 stack, some considerations about convection
must be made. For the power supply to work properly, certain temperature limits must not be
exceeded. Several factors will affect the temperature raise in the PV-5127:
• the delivered power
• the convection inside the cabinet
• the input voltage (mains) and
• the ambient temperature
Tests have shown that if the temperature at the top of the electrolytic capacitors do not exceed
105°C, the PV-5127 is thermally safe. This table shows the relationship between Uin and Tcap:
Uin[V] Tcap[°C] Tamb max.[°C] Pout[W]
10 67 60 75
18 72 55 75
24 74 53 75
30 86 41 75
All figures in the table match an ambient temperature equal to 22°C without forced cooling.
A raise in ambient temperature must be added to Tcap. This gives the max. ambient temperature:
Tamb max. = (105 –Tcap) + 22. These figures are given in the table.
If the PV-5127 is placed in an ambient temperature that is higher than indicated in the table, the
system integrator must arrange forced cooling. Temperature experiments have shown that a min.
airflow parallel to the surface of the heat sink of 0.5m/s is adequate for max. load at ambient
temperatures up to 84°C. For durability reasons, it is recommended not to use PV-5127 at ambient
temperatures exceeding 70°C at full load.
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