Emerson Unidrive M700 Installation Manual page 29

Table 3-3 Spacing required between drive / enclosure and drive / EMC filter
Drive Size
3
4
For EMC compliance:
NOTE
1. When using an external EMC filter, one filter is required for each drive.
2. Power cabling must be at least 100 mm (4 in) from the drive in all directions
3.5.2 Enclosure sizing
1. Add the dissipation figures from section 5.1.3 Power dissipation on page 80 for each drive that is
to be installed in the enclosure.
2. If an external EMC filter is to be used with each drive, add the dissipation figures from section
5.2.1 EMC filter ratings on page 96 for each external EMC filter that is to be installed in the
enclosure.
3. If the braking resistor is to be mounted inside the enclosure, add the average power figures from
for each braking resistor that is to be installed in the enclosure.
4. Calculate the total heat dissipation (in Watts) of any other equipment to be installed in the
enclosure.
5. Add the heat dissipation figures obtained above. This gives a figure in Watts for the total heat that
will be dissipated inside the enclosure.
Calculating the size of a sealed enclosure
The enclosure transfers internally generated heat into the surrounding air by natural convection (or
external forced air flow); the greater the surface area of the enclosure walls, the better is the
dissipation capability. Only the surfaces of the enclosure that are unobstructed (not in contact with a
wall or floor) can dissipate heat.
Calculate the minimum required unobstructed surface area A
P
A
-----------------------------------
=
e
k T
( –
int
Where:
A Unobstructed surface area in m
e
T
Maximum expected temperature in
ext
T
Maximum permissible temperature in
int
P Power in Watts dissipated by all heat sources in the enclosure
k Heat transmission coefficient of the enclosure material in W/m
Example
To calculate the size of an enclosure for the following:
• Two drives operating at the Normal Duty rating
• External EMC filter for each drive
• Braking resistors are to be mounted outside the enclosure
• Maximum ambient temperature inside the enclosure: 40 °C
• Maximum ambient temperature outside the enclosure: 30 °C
For example, if the power dissipation from each drive is 187 W and the power dissipation from each
external EMC filter is 9.2 W.
Total dissipation: 2 x (187 + 9.2) =392.4 W
Unidrive M/HS Frame 3 and 4 Power Installation Guide
Issue Number: 3
T
)
ext
2
(1 m
Spacing (B)
0 mm (0.00 in)
30 mm (1.18 in)
for the enclosure from:
e
2 2
= 10.9 ft )
o
C outside the enclosure
o
C inside the enclosure
2 o
/ C
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