SSI
ERP2U Power Supply Design Guide, V2.31
- 10 -
STATUS
Recommended
It is recommended the power supplies have a variable speed fan based on temperature and loading conditions.
There are three different acoustic sound power levels defined at different ambient temperatures and loading
conditions.
Table 1 Recommended Acoustic Sound Power Levels
Idle Typical Max
Ambient Temperature 28ºC 28ºC 45ºC
% Loading 30% 60% 100%
Sound Power (BA) 5.2 5.6 6.1
STATUS
Recommended
The air shall exit the power supply on the AC inlet face. The power supply shall meet all requirements with the
below system airflow impedance presented to the power supplies airflow path.
Figure 2 System Airflow Impedance
System Flow Impedance - 2U
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 5 10 15 20
Power Supply Airflow (CFM)
System Pressure (in H
2
O)
STATUS
Recommended