MVAC250-48AFD Datasheet, PDF (5/9 Pages) Murata Power Solutions Inc. – 250W 3 x 5 High Density AC-DC Power Supply Converter

THERMAL CONSIDERATIONS
MVAC250 Series
250W 3" x 5" High Density AC-DC Power Supply Converter
System thermal management is critical to the performance and reliability of the MVAC series power supplies. Performance derating curves are provided
which can be used as a guideline for what can be achieved in a system configuration with controlled airflow at various input voltage conditions.
The air flow curves are generated using an AMCA 210-99 and ASHRAE 51-1999 compliant wind tunnel with heated inlet air and a controlled CFM
providing a duct test section having a calculated average LFM. A correlation between the test setup and the actual system environment is paramount to
understanding what can be achieved in an actual system. In a power supply of this density, cooling air moving both through the unit as well as around the
unit strongly influences local temperatures. The wind tunnel test setup was constructed to produce a flow with a slight back pressure to induce both flow
conditions by providing a small gap between the power supply and duct walls of 0.5" (13mm). The optimal and characterized airflow direction is from the
input connector to the output connector (see diagram below). The P-Q flow curve for this test setup is also shown below.
13mm [0.5in] all sides
Power Supply
Air Flow
*
0.0100
0.0075
0.0050
Ambient Temperature
Measurement
0.0025
P-Q CURVE, DUCTED FLOW
Output Connector
Input Connector
64mm [2.5in]
0.0000
0
2.5
5
7.5
10
12.5
15
17.5
20
22.5
AIRFLOW-(CFM @ 0.075 lbs/cu ft air density)
The natural convection data is obtained from a horizontally mounted power supply with un-obstructed flow at room temperature. At elevated temperature
the power supply data is taken while it is surrounded by a large vented enclosure to minimize forced cross flows inherent in the elevated temperature test
system.
275
250
225
200
175
150
125
100
75
50
10
Power RaƟng at 230Vac
20
30
40
50
60
70
Ambient Temperature (Degrees C)
Nat Conv
250LFM
275
250
225
200
175
150
125
100
75
50
10
Power RaƟng at 120Vac
20
30
40
50
60
70
Ambient Temperature (Degrees C)
Nat Conv
250LFM
275
250
225
200
175
150
125
100
75
50
10
Power RaƟng at 100Vac
20
30
40
50
60
70
Ambient Temperature (Degrees C)
Nat Conv
250LFM
www.murata-ps.com/support
275
250
225
200
175
150
125
100
75
50
10
Power RaƟng at 90Vac
20
30
40
50
60
70
Ambient Temperature (Degrees C)
Nat Conv
250LFM
MVAC250.B02 Page 5 of 9