Emerson Unidrive M700 Installation Manual page 30

Power dissipation for the drives and the external EMC filters can be obtained from
NOTE
Chapter 5 Technical data on page 76.
The enclosure is to be made from painted 2 mm (0.079 in) sheet steel having a heat
transmission coefficient of 5.5 W/m
enclosure are free to dissipate heat.
The value of 5.5 W/m
values can be obtained by the supplier of the material). If in any doubt, allow for a greater
margin in the temperature rise.
Figure 3-14 Enclosure having front, sides and top panels free to dissipate heat
Insert the following values:
T
40 °C
int
T
30 °C
ext
k
5.5
P
392.4 W
The minimum required heat conducting area is then:
392.4
A
-------------------------------- -
=
e
5.5 40 30
( –
2
= 7.135 m (77.8 ft
Estimate two of the enclosure dimensions - the height (H) and depth (D), for instance. Calculate the
width (W) from:
A 2HD
–
e
W ------------------------- -
=
H D
+
Inserting H = 2m and D = 0.6 m, obtain the minimum
7.135
– (
W
---------------------------------------------------- -
=
2
=1.821 m (71.7 in)
If the enclosure is too large for the space available, it can be made smaller only by attending to one
or all of the following:
• Using a lower PWM switching frequency to reduce the dissipation in the drives
• Reducing the ambient temperature outside the enclosure, and/or applying forced-air cooling to
the outside of the enclosure
• Reducing the number of drives in the enclosure
• Removing other heat-generating equipment
30
2
/ºC can generally be used with a sheet steel enclosure (exact
H
W
)
2 2 2
) (1 m
= 10.9 ft
2 2 0.6
× × )
0.6
+
2 o
/ C. Only the top, front, and two sides of the
D
)
width:
Unidrive M/HS Frame 3 and 4 Power Installation Guide
Issue Number: 3