Select External Heatsink By Thermal Resistance - YASKAWA GA50C4009AJA Installation Manual

8 External Heatsink Selection
Figure 8.1 shows the thermal transfer principle from the drive heatsink plate to the
ambient air of the external heatsink.
A - Drive
B - Heatsink Plate
C - Thermal Compound
■

Select External Heatsink by Thermal Resistance

Use the formula to calculate the maximum thermal resistance Rθ
heatsink.
Select an external heatsink with a smaller thermal resistance than Rθ
Make sure that the dimensions of the external heatsink are close to the drive dimensions
(H × W). If the thermal resistance of the external heatsink is large, but the dimensions of
the external heatsink are near the external dimensions of the drive, select one of these
external heatsinks:
• External heatsink with more fins
• External heatsink with longer fin shape
Consider the installation environment of the drive and correct the thermal resistance
Rθ of the external heatsink. Dust and unwanted material can decrease the cooling
EHS
capacity of the external heatsink.
Note:
Apply correction factors to the thermal resistance values listed in the specification of the external heatsink in
these cases. For details, contact the external heatsink manufacturer.
• The heatsink height and width dimensions are much larger than the drive heatsink plate dimensions.
• When you install multiple drives on one heatsink.
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Figure 8.1 Thermal Equivalent Circuit Diagram
YASKAWA TOEP C710617 0SB YASKAWA AC Drive GA500 Installation Manual
D - External Heatsink
E - Heatsink Plate Temperature
EHS_max
of the external
.
EHS_max