Bosch rexroth EFC 610 Series Operating Instructions Manual page 88

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Frequency Converter Mounting
Fig. 7-17: Calculation formula of R
t : The thickness of thermal compound paste [μm]
com
k : Thermal conductivity of thermal compound paste [W/m·°C]
com
A : Heat transfer area between cold plate and external heat sink [m
com
Use the formulas above to calculate the maximum thermal resist-
●
ance of external heat sink R
thermal resistance than R
be closed to the cold plate dimensions.
Due to uneven heat transfer across the cold plate (by arrange-
●
ment of internal components), the effective area for heat transfer
is about 70 % of cold plate area. This must be considered when
calculating the thermal resistance.
For a given ambient temperature T
●
temperature T
sentially fixed, this condition must be satisfied with a proper heat
sink selection.
The table below shows the typical values of thermal resistance of cold plate.
Model
0K40
0K75
1K50
2K20
3K00
4K00
5K50
7K50
11K0
15K0
Tab. 7-14: Typical values of thermal resistance of cold plate
Bosch Rexroth AG R912005854_Edition 09
Rexroth Frequency Converter EFC x610
COMP
HSmax
HSmax
must not exceed 70 °C. As R
CPmax
R [°C/W]
CP
0.107
0.114
0.098
0.093
0.084
. Select a heat sink with a smaller
. The heat sink dimensions should
, the maximum cold plate
AMB
CP
Series
2 ]
and R is es-
COMP