YASKAWA T1000V - Page 43

2.2 Mechanical Installation
YASKAWA ELECTRIC SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual 43
Mechanical Installation
2
■ Heatsink Selection Example
This example shows heatsink selection for a CIMR-TC2V0006 drive in Normal Duty (ND) mode. The data required are
listed in the table below.
Heatsink Selection by Thermal Resistance
Substituting the example values into the formula gives:
The heatsink must have a thermal resistance lower than 1.7 K/W. When selecting the heatsink, apply a safety margin to
the calculated value in order to ensure tripless drive operation, even if the installation conditions change (temporary
higher temperature, loss of cooling ability of the external heatsink due to dust, etc.).
Feasibility Check of a Selected Heatsink
For example, a heatsink with Rθ
EHS
= 1.6 K/W would have a heatsink temperature of:
The selected heatsink can be used, but considering that the heatsink area is probably larger than the drive footprint and
the ambient conditions could change (reduced heatsink cooling ability by dirt, etc.), a heatsink with a lower Rθ
EHS
should
be chosen (e.g., Rθ
EHS
= 1.1 K/W, resulting in T
HSP
= 72.2ºC) .
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/(mK) × 6.1 × 10
-3
m
2
=
Rθ
EHS_max
=
90  - 40
27.5 W
- 0.05 K/W - 0.02 K/W
()
= 1.74 K/W
T
HSP
= 27.5 W ࡮0.05 K/W + 0.02 K/W + 1.6 K/W) + 40= 85.9 