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Mechanical
Specifications |
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HSD
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A
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B
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C
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D
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30
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30
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20
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20
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27
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40
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40
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18.3
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20
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27
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70
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70
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39.7
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21.4
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27
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140
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140
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80
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20
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27
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210
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210
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2x80
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20
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27
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280
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280
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2x100
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20
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27
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Power
Dissipation |
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This
graph shows the maximum wattage rating for each of the five possible
ressistors of standard size corresponding to the heat sin temperature.
It is assumed that all resistors are equally loaded.
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Please
consult us about non-standard lengths and resistor modules. |
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Thermal
Resistances: |
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RTH1
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RTH2
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RTH3
|
RTH4
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HSD 40
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4
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13
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0.2
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0.4
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HSD 70
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2
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8
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0.1
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0.28
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HSD 140
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1
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4.6
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0.05
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0.14
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HSD
210
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0.75
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3.3
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0.03
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0.09
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HSD
280
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0.5
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2.9
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0.02
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0.075
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RTH1
|
Wire
to Alu-house |
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RTH2
|
Alu-house
to air per resistor |
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RTH3
|
Alu-house
to heat sink per resistor |
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RTH4
|
Resistor
surface to heat sink per resistor |
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Designing: |
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The following
equations are applied by the dimensioning of the resistors at
stationary load.
It's assumed
that the air around the resistors is stationary. (Worst case).
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| WMAX
: |
Maximum
reguired load in resistor |
Following
conditions are possible:

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| TMAX
: |
Maximum
hot spot temperature reguested in resistor (TMAX < 220°C)
The lower TMAX the higher reliability and lifetime. |
| TAMB
: |
Ambient
temperature |
| RTH
: |
Thermal
resistance. Refer to table Thermal resistances |
| TH
: |
Heat
sink temperature (chassis). |
| T
: |
Temperature
on top of the Aluminium profile. |
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Insulation
Silecone
Rubber + MICA. The Silicone is UL-recognised (UL 94 HB) to a working
temperature of 220°C.
Temperatures of up to 300°C can be endured for shorter periods.
This may however cause an expansion of the silicone rubber with
a possibility of reducing the dielectric strength
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