Control Techniques Unidrive LV Series User Manual

Unidrive LV model sizes 1 to 3 Installation Guide
Issue code: uliu1
Installing the Drive 2-15
Insert the following values:
T
int
40°C
T
ext
30°C
k 5.5
P 430W
The minimum required heat conducting area is then:
A=
430
5.5(40 - 30)
= 7.8m (85ft )
e
22
(1m = 3.3 ft)
Estimate two of the enclosure dimensions — the
height (H) and depth (D), for instance. Calculate
the width (W) from:
W=
A - 2HD
H+D
e
Inserting H = 2m and D = 0.6m, obtain the minimum
width:
W=
7.8 -(2 )
2+ 0.6
m (6ft 10in)
××××
==
206
21
.
.
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 (return
to step 4 in Planning the installation)
• 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
Calculating the air-flow in a
ventilated enclosure
The dimensions of the enclosure are required only
for accommodating the equipment. The equipment
is cooled by the forced air flow.
Calculate the minimum required volume of
ventilating air from:
V=
3kP
T-T
int
ext
Where:
V Air-flow in m
3
per hour
T
ext
Maximum ambient temperature in °C
outside the enclosure
T
int
Maximum ambient temperature in °C
inside the enclosure
P Power in Watts dissipated by all heat
sources in the enclosure
k Ratio of
p
P
I
0
Where:
P
0
is the air pressure at sea level
P
I
is the air pressure at the
installation
Typically use a factor of 1.2 to 1.3, to
allow also for pressure-drops in dirty
air-filters.
Example
To calculate the size of an enclosure for the
following:
• Three UNI 3201 models
• Each Drive to operate at 6kHz
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: 670W (from step 4 in
Planning the installation)
Dissipation of each RFI filter: 60W (max) (from
step 5 in Planning the installation)
Total dissipation: 3 x (670 + 60) = 2190W
Insert the following values:
T
int
40°C
T
ext
30°C
k 1.3
P 2190W
Then:
V=
32190
40- 30
m / hr (504 ft
33
××××
==
13
854
.
/min)
(1m
3
/hr = 0.59ft
3
/min)

Control Techniques Unidrive LV Series Specifications

General

Brand	Control Techniques
Model	Unidrive LV Series
Category	DC Drives
Language	English