5
05.01
5.4 Current reduction/derating
5-128
©
Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
5.4
Current reduction/derating
The current has to be reduced if one or more of the following limitations/secon-
dary conditions apply:
S
Selected inverter pulse frequency f
T
> reference frequency f
0
S
Installation altitude>1000 m above sea level
S
Ambient temperature T
U
> 40
°
C
Notice
The currents must be reduced for I
n
, I
s6
and I
max
in the same way.
All of the relevant limitations/secondary conditions must be taken into account
with an appropriate reduction factor (refer to the calculation example, Chapter
5.4.4).
5.4.1
Pulse frequency power modules
The current should be reduced from the reference frequency f
0
onwards ac-
cording to the following rule:
X
T
= 100% –
(100% – X
L
)
(f – f
0
)
8 kHz – f
0
The pulse frequency of the power modules (inverters) must be at least factor 5
for the maximum motor frequency!
S
f
0
Pulse frequency reference frequency in accordance with the
technical data
S
f
set inverter pulse frequency
S
T
U
ambient temperature
S
X
L
power module-specific derating factor for the
inverter pulse frequency
S
X
T
derating factor for the inverter pulse frequency
S
X
H
derating factor for the ambient temperature
S
X
TU
derating factor for the installation altitude as a %
See Chapter 5.4.4
Definitions
Calculation
example
5 Power Modules
10.04
05.08