Siemens SINAMICS G130 Engineering Manual page 188

SINAMICS G150
Engineering Information
Line supply voltages
SINAMICS G150 cabinets are available for the following line supply voltages:
•
380 V – 480 V 3AC
•
500 V – 600 V 3AC
•
660 V – 690 V 3AC
The permissible voltage tolerance is ±10 % continuously and -15 % for brief periods (< 1 min). In the case of line
undervoltages within the specified tolerances, the available output power will drop accordingly unless additional
power reserves are available to increase the output current.
Usable output currents
The output currents specified in the selection and ordering data can be utilized over the entire frequency or speed
setting range, i.e. even at very low output frequencies down to zero speed.
The specified rated output current is the maximum continuous thermally permissible output current. The units have
no additional overload capacity when operating at this current.
Overload capability, load duty cycle definitions
When a drive is required to overcome breakaway torques or is subjected to high surge loads, its configuration must
take these factors into account. In such instances, it must be operated on the basis of a base load current which is
lower than the rated output current. Overload reserves are available for this purpose. The load duty cycles for
operation with low and high overloads are defined below.
•
The base load current I
•
The base load current I
These overload values apply on condition that the converter is operated at its base load current before and after the
period of overload on the basis of a load duty cycle duration of 300 s in each case.
Load duty cycle definition for low overload
Overload and overtemperature protection
SINAMICS G150 cabinets are equipped with effective overload and overtemperature protection mechanisms which
protect them against thermal overloading.
Sensors at various locations in the converter (inlet air, control electronics, rectifier heatsink, inverter heatsink)
measure the relevant temperatures and feed them into the so-called "Thermal model". This continuously calculates
the temperature at critical positions on power components. In this way the converter is effectively protected against
thermal overloads, whether they are caused by excessive current or high ambient temperatures. The so-called "I
monitoring circuit checks the level of utilization of the motor-side inverter. If the level of inverter utilization or the
temperature at any point in the converter exceeds the upper tolerance limit, the converter responds by initiating an
overload reaction parameterized in the firmware. It is possible to select whether the converter should react to
overload by reducing the output frequency and output current or the pulse frequency. Immediate shutdown can also
be parameterized.
Maximum output frequencies
The maximum output frequency for SINAMICS G150 cabinets is limited to either 160 Hz or 100 Hz due to the factory-
set pulse frequency of either f
through an increase in the pulse frequency. As the switching losses in the motor-side IGBT inverter increase in
proportion to the pulse frequency, the output current must be reduced accordingly.
SINAMICS Engineering Manual – May 2008
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© Siemens AG
for low overload is based on a load duty cycle of 110% for 60 s or 150% for 10 s.
L
for a high overload is based on a load duty cycle of 150% for 60 s or 160% for 10 s.
H
= 2.00 kHz or f = 1.25 kHz. Higher output frequencies can be obtained only
pulse pulse
Load Duty cycle definition for high overload
2
t"