6 Selecting an External Heatsink
22 YAS KAWA ELECT RI C TOBP C710606 40A YASKAWA AC Drive - J1000 Finless Installation Manual
If T
HSP
is smaller than the maximum allowable heatsink plate temperature, the selected
heatsink can be used. For verification of temperature, refer to Checking and Monitoring
Heatsink Plate Temperature on page 8.
NOTICE: Due to uneven compound thickness, uneven heat generation across the heatsink plate or other
factors, the actual heatsink plate temperature (monitored in U4-08) can be slightly different from the
calculated value. An oH drive fault may occur if the heatsink plate temperature exceeds the maximum
allowable value.
◆ Heatsink Selection Example
This example shows heatsink selection for a CIMR-J2A0006 drive in Normal Duty (ND)
mode.The data required are listed in the table below.
Item Value
P
Loss
27.5 W
T
HSP_max
90ºC
T
Amb
40ºC
Rθ
HSP
0.05 K/W
Rθ
HSP-EHS
A
th
H = 128 mm, D = 68 mm,
A
th
= 0.7 x 0.128 m x 0.068 m = 6.1 x 10
-3
m
2
λ
Comp
0.8 W/(mxK)
Thermal conductivity of “Thermal Compound G746” (Shin-Etsu Chemical Co., Ltd)
d
Comp
Recommended compound thickness: 100 μm
Rθ
HSP_EHS
=
= 0.02 K/W
100 μm
0.8 W/(mK) × 6.1 × 10
-3
m
2
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