20 YASKAWA ELECTRIC TOBP C710606 40A YASKAWA AC Drive - J1000 Finless Installation Manual
6 Selecting an External Heatsink
6 Selecting an External Heatsink
This section describes the selection of a suitable external heatsink when using a J1000
Finless drive.
◆ Data Required for Heatsink Selection
The table below shows data that are needed to select a heatsink that suits drive and
application.
Symbol Description
P
Loss
Drive heat loss
Refer to J1000 Finless Drive Watt Loss Thermal Characteristics on page 13 to check the amount
of heat loss from the heatsink plate of the drive.
T
HSP_max
Maximum heatsink plate temperature
This is the temperature at the surface of the heatsink plate. It can be monitored with U4-08. The
maximum allowable value is 90 ºC.
T
Amb
External heatsink ambient temperature (air temperature around heatsink)
Rθ
HSP
Heatsink plate thermal resistance
This value is 0.05 K/W
Rθ
HSP-EHS
Thermal resistance between the heatsink plate and the external heatsink
Can be calculated by
A
th
Heat transfer area between drive heatsink plate and external heatsink
Note: Due to uneven heat generation across the heatsink plate (by arrangement of internal
components) the effective area for heat transfer is only ~70% of heatsink plate area. This
must be considered when calculating the thermal resistance.
Refer to Dimensions on page 16 for values of H and W to calculate the area of the heatsink
plate.
λ
Comp
Thermal conductivity of the heatsink thermal compound
d
Comp
Thickness of the thermal compound
Rθ
EHS
Thermal resistance of the external heatsink
Rθ
HSP-EHS
=
d
Comp
λ
comp
A
th
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