YASKAWA V1000 Installation Manual page 25

Heatsink Selection by Thermal Resistance
■
Substituting the example values into the formula gives:
Rθ =
EHS_max
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
■
If for example a heatsink with Rθ
T = 27.5 W
HSP
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
= 72.2°C) should be chosen.
YASKAWA ELECTRIC TOBP C710606 21D YASKAWA AC Drive - V1000 Finless Installation Guide
90 - 40
(
- 0.05 K/W - 0.02 K/W
27.5 W
= 1.6 K/W is selected, the heatsink temperature will be:
EHS
0.05 K/W + 0.02 K/W + 1.6 K/W) + 40
6 Selecting an External Heatsink
)
= 1.74 K/W
(e.g. Rθ = 1.1 K/W, resulting in T
EHS EHS
= 85.9
HSP
25