Safety
Information
Introduction
Product
Information
System
configuration
Mechanical
Installation
Electrical
Installation
Getting
Started
Basic
parameters
Running
the motor
Optimization
SMARTCARD
operation
Onboard
PLC
Advanced
parameters
Technical
Data
Diagnostics
UL Listing
Information
Unidrive SPM User Guide
51
Issue Number: 3 www.controltechniques.com
5.8.2 Enclosure ambient temperature
Drive derating is required for operation in high ambient temperatures
Totally enclosing or through panel mounting the drive in either a sealed
cabinet (no airflow) or in a well ventilated cabinet makes a significant
difference on drive cooling.
The chosen method affects the ambient temperature value (T
rate
) which
should be used for any necessary derating to ensure sufficient cooling
for the whole of the drive.
The ambient temperature for the four different combinations is defined
below:
1. Totally enclosed with no air flow (<2 m/s) over the drive
T
rate
= T
int
+ 5°C
2. Totally enclosed with air flow (>2 m/s) over the drive
T
rate
= T
int
3. Through panel mounted with no airflow (<2 m/s) over the drive
T
rate
= the greater of T
ext
+5°C, or T
int
4. Through panel mounted with air flow (>2 m/s) over the drive
T
rate
= the greater of T
ext
or T
int
Where:
T
ext
= Temperature outside the cabinet
T
int
= Temperature inside the cabinet
T
rate
= Temperature used to select current rating from tables in
Chapter 14
Technical Data
.
5.8.3 Altitude derating
Multiply the maximum rated output current by the derate factor (Df) in
Figure 5-29 and the ambient correction factor (Cf) in Figure 5-30.
Rated output current = Df x Cf x Oc
Figure 5-29 Altitude derate factor
Figure 5-30 Ambient temperature correction factor
Note:
•
The ambient temperature correction factor used is for altitude
calculation only. If the ambient is less than 40
°
C the drive cannot be
over rated. The maximum permissible output currents should remain
the same as those given at 40
°
C.
•
If the drive is required to operate above 40
°
C the derates at 50
°
C
should be applied. Refer to section 14.1.1
Power and current ratings
(Derating for switching frequency and temperature)
on page 263
•
The same applies for altitude below 1000m. There should be no
over rating at lower altitude
For applications over 3000m, contact the supplier of the drive.
5.8.4 Enclosure sizing
This section looks at a method for cooling a medium power density
enclosure. By running through a worked example it brings out the issues
associated with cooling the drives when they are completely mounted
inside an enclosure.
This example only considers one possible method of enclosing the
drives and tries to highlight and solve thermal issues created by hot air
recirculating inside an enclosure. Other methods of enclosure design are
also possible, such as through panel mounting, which removes many of
the issues discussed in this chapter. Refer to section 5.7.2
Through-
panel mounting
on page 44.
The enclosure design example will use the following conditions:
•
Enclosure placed in a room with a 30
°
C ambient and an altitude
<1000m
•
Continuous output current requirement from the system = 650A
Parts used in system model:
•
1800mm (70.87in) x 800mm (31.5in) x 500mm (19.69in) enclosure
with input and output ventilation
•
2 x SPMD1404
•
2 x docking SPMC1402
•
2 x input line reactors (L1)
•
2 x output sharing chokes (L2)
1
0.95
0.9
0.85
0.8
0.75
Derat
e f
actor
(D
f)
0
500
1000
1500
2000
2500
3000
Altitude (m)
1.02
1.015
1.01
1.005
1
0.995
Correction
fa
ctor
(C
f)
20
22
24
26
28
30
32
34
36
38
Temperature ( C)
°
40
1.035
1.03
1.025
NOTE
