Page 18 of 27
17158 issue 18, August 2011
NV350 Handbook
Cooling Options:
Code
Cooling Option
Input
Voltage
Range
(Vac)
Total PSU output
power (W)
Max.
ambient
(°C)
Derating †
S, V
Forward airflow, standard fan
(fixed speed & temp.
controlled)
90 - 264 ‡
350W continuous
(400W peak if 350W
average #)
65
2.5% per °C above
50°C
S, V
Forward airflow, standard fan
(fixed speed & temp.
controlled)
115 - 264
450W continuous
(510W peak if 450W
average #)
65
2.5% per °C above
50°C
S, V
Forward airflow, standard fan
(fixed speed & temp.
controlled)
180 - 264
664W continuous
(740W peak if
600W average #)
65
2.5% per °C above
50°C
R
Reverse airflow, standard fan
90 - 264 ‡
250 W continuous
(no peak rating)
65
2.5% per °C above
50°C
Q
Forward airflow, quiet fan
90 - 264 ‡
350 W continuous
(no peak rating)
65
2.5% per °C above
50°C
T
Top fan for model K30052x
only
90 - 264 ‡
350 W continuous
(no peak rating)
65
2.5% per °C above
50°C
P
Reverse airflow, quiet fan
90 - 264 ‡
250 W continuous
(no peak rating)
60
3.8% per °C above
50°C
C, U
Customer air, fan not fitted
Refer to Customer Air Cooling section in for details.
•
† Both the total output power and the module output currents are derated by the given value.
•
‡ For input voltages between 85 and 89.9V the output power is derated to 94% of the values given for 90V
input.
•
# The PSU may output the given peak power for up to 10 seconds providing that the average power from the
PSU does not exceed the stated value.
•
Continuous, peak and average power ratings may be linearly interpolated for input voltages between 90 and
180V.
•
Global Option standby outputs (12-13.5V at 1A or 5-5.5V at 2A) should not be included when calculating total
PSU output power, but they are subject to the current deratings for operation above 50°C.
•
Global Options with output voltages between 5.01 and 5.5V have their max. output current linearly derated from
2A at 50°C ambient to 1.4A at 65°C ambient.
•
For reverse airflow cooling all B, BH and DB modules are limited to a maximum output power of 150W (total for
both channels on dual output modules).
Customer Air Cooling (options C or U):
Customer Air Cooling:
The following method must be used for determining the safe operation of PSUs when C or U option (Customer Air) is
fitted, ie fan not fitted to PSU. The minimum permitted airflow for customer air cooling is 0.5m/s.
For PSUs cooled by customer supplied airflow the components listed in the following table must not exceed the
temperatures given. Additionally ratings specified for units with an internal fan must still be complied with, eg mains
input voltage range, maximum output power, module voltage / current ratings and maximum ambient temperature.
To determine the component temperatures the heating tests must be conducted in accordance with the requirements
of the appropriate standards.
Test requirements include: PSU to be fitted in its end-use equipment and operated under the most adverse
conditions permitted in the end-use equipment handbook/specification and which will result in the highest
temperatures in the PSU. To determine the most adverse conditions consideration should be given to the end use
equipment maximum operating ambient, the PSU/assembly loading and input voltage, ventilation, end use
equipment orientation, the position of doors & covers, etc. Temperatures should be monitored using type K fine wire
thermocouples (secured with cyanoacrylate adhesive, or similar) placed on the hottest part of the component (out of
any direct airflow) and the equipment should be run until all temperatures have stabilised.
