SIEMENS
13/30
Siemens D 21.4 · 2017
Tools and configuration
Configuration notes
Power units
13
■
Configuration
(continued)
Examples of derating characteristic curves and calculation of
the permissible output current:
Current derating as a function of the ambient temperature
Current derating as a function of the installation altitude
Voltage derating as a function of the installation altitude
Example 1
A drive system is to be operated at an altitude of 2500 m
(8203 ft) at a maximum ambient temperature of 30 °C (86 °F)
and rated pulse frequency.
Since the ambient temperature is below 40 °C (104 °F), a com-
pensation calculation (installation altitude/ambient temperature)
can be applied.
Installation altitude 2500 m (8203 ft): Derating factor
k
I
= 0.965,
k
U
= 0.94
Max. ambient temperature 30 °C (86 °F): Derating factor
k
T
= 1.133
k
I
×
k
T
= 0.965 × 1.133 = 1.093
1.0 due to installation
altitude/ambient temperature compensation
k
=
k
f
× (
k
I
×
k
T
) = 1.0 × (1.0) = 1.0
Result
: Current derating is not required.
However, IEC 60664-1 stipulates that voltage derating is
required.
The units in voltage range 380 V to 480 V can be operated up to
a voltage of 480 V x 0.94 = 451 V, and the units in voltage range
660 V to 690 V up to 690 V × 0.94 = 648 V.
Example 2
When a drive line-up is configured, a Motor Module with Article
No. 6SL3320-1TE32-1AA0 is selected (rated output current
210 A, base load current for high overload 178 A). The drive line-
up is to be operated at an altitude of 3000 m (9843 ft) where
ambient temperatures could reach 35 °C (95 °F) as a result of
the installation conditions. The pulse frequency must be set to
4 kHz to provide the required dynamic response.
Installation altitude 3000 m (9843 ft): Derating factor
k
I
= 0.925,
k
U
= 0.88
Max. ambient temperature 35 °C (95 °F): Derating factor
k
T
= 1.066
k
I
×
k
T
= 0.925 × 1.066 = 0.987
not fully compensated by
installation altitude/ambient temperature
k
=
k
f
× (
k
I
×
k
T
) = 0.82 × (0.925 × 1.066) = 0.809
Result
: Current derating is required.
Where these boundary conditions apply,
•
the max. permissible continuous current of the Motor Module
is: 210 A × 0.809 = 170 A
•
the base-load current for high overloading is:
178 A × 0.809 = 144 A
IEC 60664-1 stipulates that voltage derating is required.
The selected unit can be operated up to a voltage of
480 V 3 AC × 0.88 or 720 V DC× 0.88 = 422 V 3 AC or
634 V DC. This means that a 400 V induction motor can be
operated without any restrictions. Due to the installation altitude,
however, derating might be required for the asynchronous motor
(induction motor).
G_D211_EN_00004c
Ambient temperature
(68)
(77)
(86)
(95)
(104)
(113)
(122)
(131)
(°F)
Derating factor
k
T
1.3
1.2
1.1
1.0
0.9
0.8
25
20
30
35
40
45
50
55
°C
1000
2000
m
0
3000
4000
100
95
90
85
(3281)
(6562)
(9843)
(ft)
(13124)
1.00
0.95
0.85
0.90
Derating factor
k
I
Installation altitude above sea level
Permissible continuous current in %
of rated current
G_D211_EN_00005b
(3281)
(6562)
(9843)
(ft)
(13124)
1.0
0.9
0.7
0.8
Derating factor
k
U
Installation altitude above sea level
Permissible input voltage in %
of rated voltage
G_D211_EN_00006b
1000
2000
m
0
3000
4000
100
90
80
70
© Siemens AG 2017