Siemens SINAMICS G130 Engineering Manual page 166

Fundamental Principles and System Description
Engineering Information
If the criteria described above are applied to the SINAMICS G130, G150 and S150 converters and to the SINAMICS
S120 inverter Motor Modules (Chassis and Cabinet Modules), then free load duty cycles are permissible whenever
the following conditions are fulfilled:
The short-time current I
ShortTime
(In the case of parallel connections of S120 Motor Modules, I
or one Motor Module)
The current derating factor k
of the converter or inverter:
Key to equation:
·
k Current derating factor (total derating factor),
D
·
k Derating factor for increased ambient temperature in the 40 °C to 50 °C / 55 °C range,
Temp
·
k Derating factor for pulse frequencies higher than the factory-set pulse frequency,
Pulse
·
k Derating factor for parallel operation of S120 Motor Modules,
Parallel
·
k Derating factor for periodic load duty cycles in order to protect against premature IGBT failure..
IGBT
The derating factors k
Temp
sections of this engineering manual. With respect to the derating factor k
converters at increased pulse frequency" must be observed.
The derating factor k
Parallel
The derating factor k is unit-specific and must only be applied in the case of regularly recurring, periodic load duty
IGBT
cycles (e.g. shears, presses, centrifuges, amusement rides in theme parks, etc.) in order to limit the temperature
swing ΔT in the IGBT and thus to protect against premature IGBT failure.
Chip
The following derating characteristics specify the
derating factor k as a function of the current ratio
IGBT
ΔI = I / I and the load duty cycle duration
ShortTime BaseLoad
T.
The assignment between derating characteristics 1 to 3
and SINAMICS G130 and G150 converters, SINAMICS
S120 Motor Modules (air-cooled and liquid-cooled) and
SINAMICS S150 converters are given in the assignment
table on the following page.
Derating factor k as a function of the current ratio ΔI = I
IGBT
SINAMICS Engineering Manual – November 2015
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Ó Siemens AG
must be limited to values less than 1.5
takes into account all influences which necessitate a reduction in the short-time current
D
= ×
k k k
D Temp
and k are unit-specific and can be found in the appropriate catalogs or the unit-specific
Pulse
is generally 0.95 for SINAMICS S120 Motor Modules.
k
* D*
is the short-time current of one inverter section
ShortTime
× ×
k k
.
Pulse Parallel IGBT
, the information in section "Operation of
Pulse
/ I and the load duty cycle duration T
Short Time Base Load
I .
H