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Control Techniques Unidrive LV Series User Manual

Control Techniques Unidrive LV Series
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Unidrive
LV
model sizes 1 to 3 Installation Guide
Issue code: uliu1
2-14 Installing the Drive
2.4 Calculating the
enclosure size
STEP 1 Add the dissipation figures from step 4 of
Planning the installation for each Drive that is to
be installed in the enclosure. Make a note of
this step number and the total value.
S
TEP 2 If an RFI filter is to be used with each
Drive, add the dissipation figures from step 5 of
Planning the installation for each RFI filter that is
to be installed in the enclosure. Make a note of
this step number and the total value.
S
TEP 3 If the braking resistor is to be mounted
inside the enclosure, add the average power
figures from step 8 of Planning the installation for
each braking resistor that is to be installed in
the enclosure. Make a note of this step number
and the total value.
S
TEP 4 Make a note of this step number and the
total heat dissipation (in Watts) of any other
equipment to be installed in the enclosure.
S
TEP 5 Add the heat dissipation figures obtained
(as appropriate) from steps 1, 2, 3 and 4 above.
This gives a figure in Watts for the total heat
that will be dissipated inside the enclosure.
Make a note of this figure and the step number.
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
e
for the enclosure from:
A=
P
k(T - T )
e
int ext
Where:
A
e
Unobstructed surface area in m
2
(1m
2
= 10.8 ft
2
)
T
ext
Maximum expected ambient
temperature in °C outside the enclosure
T
int
Maximum permissible ambient
temperature in °C inside the enclosure
P Power in Watts dissipated by all heat
sources in the enclosure
k Heat transmission coefficient of the
enclosure material in W/m
2
/°C
Example
To calculate the size of an enclosure for the
following:
Two UNI 1205 models
Each Drive to operate at 4.5kHz
PWM
switching frequency
RFI 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
Dissipation of each Drive: 190W (from step 4 in
Planning the installation)
Dissipation of each RFI filter: 25W (max) (from
step 5 in Planning the installation)
Total dissipation: 2 x (190 + 25) = 430W
The enclosure is to be made from painted 2mm
(
3
/
32
in) sheet steel having a heat transmission
coefficient of 5.5W/m
2
/°C. Only the top, front, and
two sides of the enclosure are to be free to
dissipate heat.
Figure 2–6 Enclosure having front, sides and
top panels free to dissipate heat

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Control Techniques Unidrive LV Series Specifications

General IconGeneral
BrandControl Techniques
ModelUnidrive LV Series
CategoryDC Drives
LanguageEnglish

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